Merge branch 'main' into sparsehistogram

2022-05-15 14:16:16 +02:00 · 2022-05-15 14:16:16 +02:00 · b2372302ca
parent 294cca4252 5d584e2717
commit b2372302ca
56 changed files with 2685 additions and 478 deletions
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@ -1,7 +1,7 @@
 version: 2.1
 orbs:
-  go: circleci/go@0.2.0
-  prometheus: prometheus/prometheus@0.15.0
+  go: circleci/go@1.7.1
+  prometheus: prometheus/prometheus@0.16.0
 jobs:
  test:
    parameters:
@ -17,8 +17,7 @@ jobs:
        type: boolean
        default: true
    docker:
-      - image: circleci/golang:<< parameters.go_version >>
-    working_directory: /go/src/github.com/prometheus/client_golang
+      - image: cimg/go:<< parameters.go_version >>
    steps:
      - checkout
      - when:
@ -47,18 +46,6 @@ workflows:
  client_golang:
    jobs:
      # Refer to README.md for the currently supported versions.
-      - test:
-          name: go-1-13
-          go_version: "1.13"
-          run_lint: true
-      - test:
-          name: go-1-14
-          go_version: "1.14"
-          run_lint: true
-      - test:
-          name: go-1-15
-          go_version: "1.15"
-          run_lint: true
      - test:
          name: go-1-16
          go_version: "1.16"
@ -67,4 +54,10 @@ workflows:
          name: go-1-17
          go_version: "1.17"
          run_lint: true
+      - test:
+          name: go-1-18
+          go_version: "1.18"
+          run_lint: true
+          # Style and unused/missing packages are only checked against
+          # the latest supported Go version.
          run_style_and_unused: true
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: "gomod"
+    directory: "/"
+    schedule:
+      interval: "monthly"
--- a/.github/stale.yml
+++ b/.github/stale.yml
@ -0,0 +1,88 @@
+# Configuration for probot-stale - https://github.com/probot/stale
+
+# Number of days of inactivity before an Issue or Pull Request becomes stale
+# daysUntilStale: 30
+
+# Number of days of inactivity before an Issue or Pull Request with the stale label is closed.
+# Set to false to disable. If disabled, issues still need to be closed manually, but will remain marked as stale.
+# daysUntilClose: 7
+
+# NOTICE: Check below for the individual settings for each type of event.
+
+# Only issues or pull requests with all of these labels are check if stale. Defaults to `[]` (disabled)
+onlyLabels: []
+
+# Issues or Pull Requests with these labels will never be considered stale. Set to `[]` to disable
+exemptLabels:
+  - pinned
+  - security
+  - keep-open
+  - wip
+  - "[Status] Maybe Later"
+
+# Set to true to ignore issues in a project (defaults to false)
+exemptProjects: true # default: false
+
+# Set to true to ignore issues in a milestone (defaults to false)
+exemptMilestones: true # default: false
+
+# Set to true to ignore issues with an assignee (defaults to false)
+exemptAssignees: false
+
+# Label to use when marking as stale
+staleLabel: stale
+
+# Comment to post when marking as stale. Set to `false` to disable
+# markComment: >
+#  This issue has been automatically marked as stale because it has not had
+#  recent activity. It will be closed if no further activity occurs. Thank you
+#  for your contributions.
+
+# Comment to post when removing the stale label.
+# unmarkComment: >
+#   Your comment here.
+
+# Comment to post when closing a stale Issue or Pull Request.
+# closeComment: >
+#   Your comment here.
+
+# Limit the number of actions per hour, from 1-30. Default is 30
+limitPerRun: 30
+
+# Limit to only `issues` or `pulls`
+# only: issues
+
+# Optionally, specify configuration settings that are specific to just 'issues' or 'pulls':
+# pulls:
+#   daysUntilStale: 30
+#   markComment: >
+#     This pull request has been automatically marked as stale because it has not had
+#     recent activity. It will be closed if no further activity occurs. Thank you
+#     for your contributions.
+
+# issues:
+#   exemptLabels:
+#     - confirmed
+
+pull:
+  daysUntilClose: 14
+  daysUntilStale: 60
+  markComment: >
+    Hello 👋 Looks like there was no activity on this amazing PR for the last 60 days.
+    **Do you mind updating us on the status?** Is there anything we can help with? If you plan to still work on it, just comment on this PR or push a commit. Thanks! 🤗
+    
+    If there will be no activity in the next 2 weeks, this issue will be closed (we can always reopen a PR if you get back to this!).
+  # unmarkComment: No need for unmark comment.
+  closeComment: >
+    Closing for now as promised, let us know if you need this to be reopened! 🤗
+issues:
+  daysUntilClose: 90
+  daysUntilStale: 180
+  markComment: >
+    Hello 👋 Looks like there was no activity on this issue for the last 3 months.
+    **Do you mind updating us on the status?** Is this still reproducible or needed? If yes, just comment on this PR or push a commit. Thanks! 🤗
+    
+    If there will be no activity in the next 4 weeks, this issue will be closed (we can always reopen an issue if we need!).
+  # unmarkComment: No need for unmark comment.
+  closeComment: >
+    Closing for now as promised, let us know if you need this to be reopened! 🤗
--- a/.github/workflows/codeql-analysis.yml
+++ b/.github/workflows/codeql-analysis.yml
@ -0,0 +1,70 @@
+# For most projects, this workflow file will not need changing; you simply need
+# to commit it to your repository.
+#
+# You may wish to alter this file to override the set of languages analyzed,
+# or to provide custom queries or build logic.
+#
+# ******** NOTE ********
+# We have attempted to detect the languages in your repository. Please check
+# the `language` matrix defined below to confirm you have the correct set of
+# supported CodeQL languages.
+#
+name: "CodeQL"
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    # The branches below must be a subset of the branches above
+    branches: [ main ]
+  schedule:
+    - cron: '31 21 * * 6'
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+
+    strategy:
+      fail-fast: false
+      matrix:
+        language: [ 'go' ]
+        # CodeQL supports [ 'cpp', 'csharp', 'go', 'java', 'javascript', 'python', 'ruby' ]
+        # Learn more about CodeQL language support at https://git.io/codeql-language-support
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v2
+
+    # Initializes the CodeQL tools for scanning.
+    - name: Initialize CodeQL
+      uses: github/codeql-action/init@v1
+      with:
+        languages: ${{ matrix.language }}
+        # If you wish to specify custom queries, you can do so here or in a config file.
+        # By default, queries listed here will override any specified in a config file.
+        # Prefix the list here with "+" to use these queries and those in the config file.
+        # queries: ./path/to/local/query, your-org/your-repo/queries@main
+
+    # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
+    # If this step fails, then you should remove it and run the build manually (see below)
+    - name: Autobuild
+      uses: github/codeql-action/autobuild@v1
+
+    # ℹ️ Command-line programs to run using the OS shell.
+    # 📚 https://git.io/JvXDl
+
+    # ✏️ If the Autobuild fails above, remove it and uncomment the following three lines
+    #    and modify them (or add more) to build your code if your project
+    #    uses a compiled language
+
+    #- run: |
+    #   make bootstrap
+    #   make release
+
+    - name: Perform CodeQL Analysis
+      uses: github/codeql-action/analyze@v1
--- a/.github/workflows/golangci-lint.yml
+++ b/.github/workflows/golangci-lint.yml
@ -9,13 +9,6 @@ on:
      - ".github/workflows/golangci-lint.yml"
      - ".golangci.yml"
  pull_request:
-    paths:
-      - "go.sum"
-      - "go.mod"
-      - "**.go"
-      - "scripts/errcheck_excludes.txt"
-      - ".github/workflows/golangci-lint.yml"
-      - ".golangci.yml"

 jobs:
  golangci:
@ -23,9 +16,15 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
-        uses: actions/checkout@v2
-
-      - name: Lint
-        uses: golangci/golangci-lint-action@v2
+        uses: actions/checkout@v3
+      - name: install Go
+        uses: actions/setup-go@v2
        with:
-          version: v1.42.0
+          go-version: 1.18.x
+      - name: Install snmp_exporter/generator dependencies
+        run: sudo apt-get update && sudo apt-get -y install libsnmp-dev
+        if: github.repository == 'prometheus/snmp_exporter'
+      - name: Lint
+        uses: golangci/golangci-lint-action@v3.1.0
+        with:
+          version: v1.45.2
--- a/.gitignore
+++ b/.gitignore
@ -1,6 +1,7 @@
 # Examples
 examples/simple/simple
 examples/random/random
+examples/gocollector/gocollector

 # Typical backup/temporary files of editors
 *~
@ -11,7 +12,7 @@ examples/random/random
 vendor/

 # The remainder of this file is taken from
-# https://github.com/github/gitignore/blob/master/Go.gitignore
+# https://github.com/github/gitignore/blob/main/Go.gitignore

 # Binaries for programs and plugins
 *.exe
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -1,3 +1,17 @@
+## Unreleased
+
+* [CHANGE] Minimum required Go version is now 1.16.
+
+## 1.12.2 / 2022-05-13
+
+* [CHANGE] Added `collectors.WithGoCollections` that allows to choose what collection of Go runtime metrics user wants: Equivalent of [`MemStats` structure](https://pkg.go.dev/runtime#MemStats) configured using `GoRuntimeMemStatsCollection`, new based on dedicated [runtime/metrics](https://pkg.go.dev/runtime/metrics) metrics represented by `GoRuntimeMetricsCollection` option, or both by specifying `GoRuntimeMemStatsCollection | GoRuntimeMetricsCollection` flag.
+* [CHANGE] :warning: Change in `collectors.NewGoCollector` metrics: Reverting addition of new ~80 runtime metrics by default. You can enable this back with `GoRuntimeMetricsCollection` option or `GoRuntimeMemStatsCollection | GoRuntimeMetricsCollection` for smooth transition.
+* [BUGFIX] Fixed the bug that causes generated histogram metric names to end with `_total`. ⚠️ This changes 3 metric names in the new Go collector that was reverted from default in this release.
+  * `go_gc_heap_allocs_by_size_bytes_total` -> `go_gc_heap_allocs_by_size_bytes`,
+  * `go_gc_heap_frees_by_size_bytes_total` -> `go_gc_heap_allocs_by_size_bytes`
+  * `go_gc_pauses_seconds_total` -> `go_gc_pauses_seconds`.
+* [CHANCE] Removed `-Inf` buckets from new Go Collector histograms.
+
 ## 1.12.1 / 2022-01-29

 * [BUGFIX] Make the Go 1.17 collector concurrency-safe #969
--- a/CODE_OF_CONDUCT.md
+++ b/CODE_OF_CONDUCT.md
@ -1,3 +1,3 @@
-## Prometheus Community Code of Conduct
+# Prometheus Community Code of Conduct

-Prometheus follows the [CNCF Code of Conduct](https://github.com/cncf/foundation/blob/master/code-of-conduct.md).
+Prometheus follows the [CNCF Code of Conduct](https://github.com/cncf/foundation/blob/main/code-of-conduct.md).
--- a/17
+++ b/17
@ -1,7 +1,15 @@
 # This Dockerfile builds an image for a client_golang example.
 #
 # Use as (from the root for the client_golang repository):
-#    docker build -f examples/$name/Dockerfile -t prometheus/golang-example-$name .
+#    docker build -f Dockerfile -t prometheus/golang-example .
+
+# Run as
+#    docker run -P prometheus/golang-example /random
+# or
+#    docker run -P prometheus/golang-example /simple
+
+# Test as
+#    curl $ip:$port/metrics

 # Builder image, where we build the example.
 FROM golang:1 AS builder
@ -13,11 +21,14 @@ WORKDIR /go/src/github.com/prometheus/client_golang/examples/random
 RUN CGO_ENABLED=0 GOOS=linux go build -a -tags netgo -ldflags '-w'
 WORKDIR /go/src/github.com/prometheus/client_golang/examples/simple
 RUN CGO_ENABLED=0 GOOS=linux go build -a -tags netgo -ldflags '-w'
+WORKDIR /go/src/github.com/prometheus/client_golang/examples/gocollector
+RUN CGO_ENABLED=0 GOOS=linux go build -a -tags netgo -ldflags '-w'

 # Final image.
 FROM quay.io/prometheus/busybox:latest
 LABEL maintainer="The Prometheus Authors <prometheus-developers@googlegroups.com>"
 COPY --from=builder /go/src/github.com/prometheus/client_golang/examples/random \
-    /go/src/github.com/prometheus/client_golang/examples/simple ./
+    /go/src/github.com/prometheus/client_golang/examples/simple \
+    /go/src/github.com/prometheus/client_golang/examples/gocollector ./
 EXPOSE 8080
-CMD ["echo", "Please run an example. Either /random or /simple"]
+CMD ["echo", "Please run an example. Either /random, /simple or /gocollector"]
--- a/Makefile.common
+++ b/Makefile.common
@ -83,7 +83,7 @@ PROMU_URL     := https://github.com/prometheus/promu/releases/download/v$(PROMU_

 GOLANGCI_LINT :=
 GOLANGCI_LINT_OPTS ?=
-GOLANGCI_LINT_VERSION ?= v1.42.0
+GOLANGCI_LINT_VERSION ?= v1.45.2
 # golangci-lint only supports linux, darwin and windows platforms on i386/amd64.
 # windows isn't included here because of the path separator being different.
 ifeq ($(GOHOSTOS),$(filter $(GOHOSTOS),linux darwin))
--- a/README.md
+++ b/README.md
@ -1,15 +1,16 @@
 # Prometheus Go client library

-[![CircleCI](https://circleci.com/gh/prometheus/client_golang/tree/master.svg?style=svg)](https://circleci.com/gh/prometheus/client_golang/tree/master)
+[![CircleCI](https://circleci.com/gh/prometheus/client_golang/tree/main.svg?style=svg)](https://circleci.com/gh/prometheus/client_golang/tree/main)
 [![Go Report Card](https://goreportcard.com/badge/github.com/prometheus/client_golang)](https://goreportcard.com/report/github.com/prometheus/client_golang)
 [![Go Reference](https://pkg.go.dev/badge/github.com/prometheus/client_golang.svg)](https://pkg.go.dev/github.com/prometheus/client_golang)
+[![Slack](https://img.shields.io/badge/join%20slack-%23prometheus--client_golang-brightgreen.svg)](https://slack.cncf.io/)

 This is the [Go](http://golang.org) client library for
 [Prometheus](http://prometheus.io). It has two separate parts, one for
 instrumenting application code, and one for creating clients that talk to the
 Prometheus HTTP API.

-__This library requires Go1.13 or later.__
+__This library requires Go1.16 or later.__

 ## Important note about releases and stability

@ -34,13 +35,13 @@ coexist for a while to enable a convenient transition.
 [![code-coverage](http://gocover.io/_badge/github.com/prometheus/client_golang/prometheus)](http://gocover.io/github.com/prometheus/client_golang/prometheus) [![Go Reference](https://pkg.go.dev/badge/github.com/prometheus/client_golang/prometheus.svg)](https://pkg.go.dev/github.com/prometheus/client_golang/prometheus)

 The
-[`prometheus` directory](https://github.com/prometheus/client_golang/tree/master/prometheus)
+[`prometheus` directory](https://github.com/prometheus/client_golang/tree/main/prometheus)
 contains the instrumentation library. See the
 [guide](https://prometheus.io/docs/guides/go-application/) on the Prometheus
 website to learn more about instrumenting applications.

 The
-[`examples` directory](https://github.com/prometheus/client_golang/tree/master/examples)
+[`examples` directory](https://github.com/prometheus/client_golang/tree/main/examples)
 contains simple examples of instrumented code.

 ## Client for the Prometheus HTTP API
@ -48,7 +49,7 @@ contains simple examples of instrumented code.
 [![code-coverage](http://gocover.io/_badge/github.com/prometheus/client_golang/api/prometheus/v1)](http://gocover.io/github.com/prometheus/client_golang/api/prometheus/v1) [![Go Reference](https://pkg.go.dev/badge/github.com/prometheus/client_golang/api.svg)](https://pkg.go.dev/github.com/prometheus/client_golang/api)

 The
-[`api/prometheus` directory](https://github.com/prometheus/client_golang/tree/master/api/prometheus)
+[`api/prometheus` directory](https://github.com/prometheus/client_golang/tree/main/api/prometheus)
 contains the client for the
 [Prometheus HTTP API](http://prometheus.io/docs/querying/api/). It allows you
 to write Go applications that query time series data from a Prometheus
@ -57,12 +58,14 @@ server. It is still in alpha stage.
 ## Where is `model`, `extraction`, and `text`?

 The `model` packages has been moved to
-[`prometheus/common/model`](https://github.com/prometheus/common/tree/master/model).
+[`prometheus/common/model`](https://github.com/prometheus/common/tree/main/model).

 The `extraction` and `text` packages are now contained in
-[`prometheus/common/expfmt`](https://github.com/prometheus/common/tree/master/expfmt).
+[`prometheus/common/expfmt`](https://github.com/prometheus/common/tree/main/expfmt).

 ## Contributing and community

 See the [contributing guidelines](CONTRIBUTING.md) and the
 [Community section](http://prometheus.io/community/) of the homepage.
+
+`clint_golang` community is also present on the CNCF Slack `#prometheus-client_golang`.
--- a/SECURITY.md
+++ b/SECURITY.md
@ -3,4 +3,4 @@
 The Prometheus security policy, including how to report vulnerabilities, can be
 found here:

-https://prometheus.io/docs/operating/security/
+<https://prometheus.io/docs/operating/security/>
--- a/api/client.go
+++ b/api/client.go
@ -17,6 +17,7 @@ package api
 import (
 	"bytes"
 	"context"
+	"errors"
 	"net"
 	"net/http"
 	"net/url"
@ -40,6 +41,10 @@ type Config struct {
 	// The address of the Prometheus to connect to.
 	Address string

+	// Client is used by the Client to drive HTTP requests. If not provided,
+	// a new one based on the provided RoundTripper (or DefaultRoundTripper) will be used.
+	Client *http.Client
+
 	// RoundTripper is used by the Client to drive HTTP requests. If not
 	// provided, DefaultRoundTripper will be used.
 	RoundTripper http.RoundTripper
@ -52,6 +57,22 @@ func (cfg *Config) roundTripper() http.RoundTripper {
 	return cfg.RoundTripper
 }

+func (cfg *Config) client() http.Client {
+	if cfg.Client == nil {
+		return http.Client{
+			Transport: cfg.roundTripper(),
+		}
+	}
+	return *cfg.Client
+}
+
+func (cfg *Config) validate() error {
+	if cfg.Client != nil && cfg.RoundTripper != nil {
+		return errors.New("api.Config.RoundTripper and api.Config.Client are mutually exclusive")
+	}
+	return nil
+}
+
 // Client is the interface for an API client.
 type Client interface {
 	URL(ep string, args map[string]string) *url.URL
@ -68,9 +89,13 @@ func NewClient(cfg Config) (Client, error) {
 	}
 	u.Path = strings.TrimRight(u.Path, "/")

+	if err := cfg.validate(); err != nil {
+		return nil, err
+	}
+
 	return &httpClient{
 		endpoint: u,
-		client:   http.Client{Transport: cfg.roundTripper()},
+		client:   cfg.client(),
 	}, nil
 }

--- a/api/prometheus/v1/api.go
+++ b/api/prometheus/v1/api.go
@ -238,9 +238,9 @@ type API interface {
 	// LabelValues performs a query for the values of the given label, time range and matchers.
 	LabelValues(ctx context.Context, label string, matches []string, startTime time.Time, endTime time.Time) (model.LabelValues, Warnings, error)
 	// Query performs a query for the given time.
-	Query(ctx context.Context, query string, ts time.Time) (model.Value, Warnings, error)
+	Query(ctx context.Context, query string, ts time.Time, opts ...Option) (model.Value, Warnings, error)
 	// QueryRange performs a query for the given range.
-	QueryRange(ctx context.Context, query string, r Range) (model.Value, Warnings, error)
+	QueryRange(ctx context.Context, query string, r Range, opts ...Option) (model.Value, Warnings, error)
 	// QueryExemplars performs a query for exemplars by the given query and time range.
 	QueryExemplars(ctx context.Context, query string, startTime time.Time, endTime time.Time) ([]ExemplarQueryResult, error)
 	// Buildinfo returns various build information properties about the Prometheus server
@ -818,10 +818,35 @@ func (h *httpAPI) LabelValues(ctx context.Context, label string, matches []strin
 	return labelValues, w, json.Unmarshal(body, &labelValues)
 }

-func (h *httpAPI) Query(ctx context.Context, query string, ts time.Time) (model.Value, Warnings, error) {
+type apiOptions struct {
+	timeout time.Duration
+}
+
+type Option func(c *apiOptions)
+
+// WithTimeout can be used to provide an optional query evaluation timeout for Query and QueryRange.
+// https://prometheus.io/docs/prometheus/latest/querying/api/#instant-queries
+func WithTimeout(timeout time.Duration) Option {
+	return func(o *apiOptions) {
+		o.timeout = timeout
+	}
+}
+
+func (h *httpAPI) Query(ctx context.Context, query string, ts time.Time, opts ...Option) (model.Value, Warnings, error) {
+
 	u := h.client.URL(epQuery, nil)
 	q := u.Query()

+	opt := &apiOptions{}
+	for _, o := range opts {
+		o(opt)
+	}
+
+	d := opt.timeout
+	if d > 0 {
+		q.Set("timeout", d.String())
+	}
+
 	q.Set("query", query)
 	if !ts.IsZero() {
 		q.Set("time", formatTime(ts))
@ -836,7 +861,7 @@ func (h *httpAPI) Query(ctx context.Context, query string, ts time.Time) (model.
 	return model.Value(qres.v), warnings, json.Unmarshal(body, &qres)
 }

-func (h *httpAPI) QueryRange(ctx context.Context, query string, r Range) (model.Value, Warnings, error) {
+func (h *httpAPI) QueryRange(ctx context.Context, query string, r Range, opts ...Option) (model.Value, Warnings, error) {
 	u := h.client.URL(epQueryRange, nil)
 	q := u.Query()

@ -845,6 +870,16 @@ func (h *httpAPI) QueryRange(ctx context.Context, query string, r Range) (model.
 	q.Set("end", formatTime(r.End))
 	q.Set("step", strconv.FormatFloat(r.Step.Seconds(), 'f', -1, 64))

+	opt := &apiOptions{}
+	for _, o := range opts {
+		o(opt)
+	}
+
+	d := opt.timeout
+	if d > 0 {
+		q.Set("timeout", d.String())
+	}
+
 	_, body, warnings, err := h.client.DoGetFallback(ctx, u, q)
 	if err != nil {
 		return nil, warnings, err
@ -1133,27 +1168,31 @@ func (h *apiClientImpl) Do(ctx context.Context, req *http.Request) (*http.Respon
 // DoGetFallback will attempt to do the request as-is, and on a 405 or 501 it
 // will fallback to a GET request.
 func (h *apiClientImpl) DoGetFallback(ctx context.Context, u *url.URL, args url.Values) (*http.Response, []byte, Warnings, error) {
-	req, err := http.NewRequest(http.MethodPost, u.String(), strings.NewReader(args.Encode()))
+	encodedArgs := args.Encode()
+	req, err := http.NewRequest(http.MethodPost, u.String(), strings.NewReader(encodedArgs))
 	if err != nil {
 		return nil, nil, nil, err
 	}
 	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	// Following comment originates from https://pkg.go.dev/net/http#Transport
+	// Transport only retries a request upon encountering a network error if the request is
+	// idempotent and either has no body or has its Request.GetBody defined. HTTP requests
+	// are considered idempotent if they have HTTP methods GET, HEAD, OPTIONS, or TRACE; or
+	// if their Header map contains an "Idempotency-Key" or "X-Idempotency-Key" entry. If the
+	// idempotency key value is a zero-length slice, the request is treated as idempotent but
+	// the header is not sent on the wire.
+	req.Header["Idempotency-Key"] = nil

 	resp, body, warnings, err := h.Do(ctx, req)
 	if resp != nil && (resp.StatusCode == http.StatusMethodNotAllowed || resp.StatusCode == http.StatusNotImplemented) {
-		u.RawQuery = args.Encode()
+		u.RawQuery = encodedArgs
 		req, err = http.NewRequest(http.MethodGet, u.String(), nil)
 		if err != nil {
 			return nil, nil, warnings, err
 		}
-
-	} else {
-		if err != nil {
-			return resp, body, warnings, err
-		}
-		return resp, body, warnings, nil
+		return h.Do(ctx, req)
 	}
-	return h.Do(ctx, req)
+	return resp, body, warnings, err
 }

 func formatTime(t time.Time) string {
--- a/api/prometheus/v1/api_test.go
+++ b/api/prometheus/v1/api_test.go
@ -170,15 +170,15 @@ func TestAPIs(t *testing.T) {
 		}
 	}

-	doQuery := func(q string, ts time.Time) func() (interface{}, Warnings, error) {
+	doQuery := func(q string, ts time.Time, opts ...Option) func() (interface{}, Warnings, error) {
 		return func() (interface{}, Warnings, error) {
-			return promAPI.Query(context.Background(), q, ts)
+			return promAPI.Query(context.Background(), q, ts, opts...)
 		}
 	}

-	doQueryRange := func(q string, rng Range) func() (interface{}, Warnings, error) {
+	doQueryRange := func(q string, rng Range, opts ...Option) func() (interface{}, Warnings, error) {
 		return func() (interface{}, Warnings, error) {
-			return promAPI.QueryRange(context.Background(), q, rng)
+			return promAPI.QueryRange(context.Background(), q, rng, opts...)
 		}
 	}

@ -246,7 +246,7 @@ func TestAPIs(t *testing.T) {

 	queryTests := []apiTest{
 		{
-			do: doQuery("2", testTime),
+			do: doQuery("2", testTime, WithTimeout(5*time.Second)),
 			inRes: &queryResult{
 				Type: model.ValScalar,
 				Result: &model.Scalar{
@ -258,8 +258,9 @@ func TestAPIs(t *testing.T) {
 			reqMethod: "POST",
 			reqPath:   "/api/v1/query",
 			reqParam: url.Values{
-				"query": []string{"2"},
-				"time":  []string{testTime.Format(time.RFC3339Nano)},
+				"query":   []string{"2"},
+				"time":    []string{testTime.Format(time.RFC3339Nano)},
+				"timeout": []string{(5 * time.Second).String()},
 			},
 			res: &model.Scalar{
 				Value:     2,
@ -365,16 +366,17 @@ func TestAPIs(t *testing.T) {
 				Start: testTime.Add(-time.Minute),
 				End:   testTime,
 				Step:  time.Minute,
-			}),
+			}, WithTimeout(5*time.Second)),
 			inErr: fmt.Errorf("some error"),

 			reqMethod: "POST",
 			reqPath:   "/api/v1/query_range",
 			reqParam: url.Values{
-				"query": []string{"2"},
-				"start": []string{testTime.Add(-time.Minute).Format(time.RFC3339Nano)},
-				"end":   []string{testTime.Format(time.RFC3339Nano)},
-				"step":  []string{time.Minute.String()},
+				"query":   []string{"2"},
+				"start":   []string{testTime.Add(-time.Minute).Format(time.RFC3339Nano)},
+				"end":     []string{testTime.Format(time.RFC3339Nano)},
+				"step":    []string{time.Minute.String()},
+				"timeout": []string{(5 * time.Second).String()},
 			},
 			err: fmt.Errorf("some error"),
 		},
--- a/api/prometheus/v1/example_test.go
+++ b/api/prometheus/v1/example_test.go
@ -39,7 +39,7 @@ func ExampleAPI_query() {
 	v1api := v1.NewAPI(client)
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()
-	result, warnings, err := v1api.Query(ctx, "up", time.Now())
+	result, warnings, err := v1api.Query(ctx, "up", time.Now(), v1.WithTimeout(5*time.Second))
 	if err != nil {
 		fmt.Printf("Error querying Prometheus: %v\n", err)
 		os.Exit(1)
@ -67,7 +67,7 @@ func ExampleAPI_queryRange() {
 		End:   time.Now(),
 		Step:  time.Minute,
 	}
-	result, warnings, err := v1api.QueryRange(ctx, "rate(prometheus_tsdb_head_samples_appended_total[5m])", r)
+	result, warnings, err := v1api.QueryRange(ctx, "rate(prometheus_tsdb_head_samples_appended_total[5m])", r, v1.WithTimeout(5*time.Second))
 	if err != nil {
 		fmt.Printf("Error querying Prometheus: %v\n", err)
 		os.Exit(1)
--- a/examples/gocollector/main.go
+++ b/examples/gocollector/main.go
@ -0,0 +1,55 @@
+// Copyright 2022 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build go1.17
+// +build go1.17
+
+// A minimal example of how to include Prometheus instrumentation.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/collectors"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+var addr = flag.String("listen-address", ":8080", "The address to listen on for HTTP requests.")
+
+func main() {
+	flag.Parse()
+
+	// Create a new registry.
+	reg := prometheus.NewRegistry()
+
+	// Add Go module build info.
+	reg.MustRegister(collectors.NewBuildInfoCollector())
+	reg.MustRegister(collectors.NewGoCollector(
+		collectors.WithGoCollections(collectors.GoRuntimeMemStatsCollection | collectors.GoRuntimeMetricsCollection),
+	))
+
+	// Expose the registered metrics via HTTP.
+	http.Handle("/metrics", promhttp.HandlerFor(
+		reg,
+		promhttp.HandlerOpts{
+			// Opt into OpenMetrics to support exemplars.
+			EnableOpenMetrics: true,
+		},
+	))
+	fmt.Println("Hello world from new Go Collector!")
+	log.Fatal(http.ListenAndServe(*addr, nil))
+}
--- a/examples/random/main.go
+++ b/examples/random/main.go
@ -26,6 +26,7 @@ import (
 	"time"

 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/collectors"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 )

@ -68,7 +69,7 @@ func main() {
 	prometheus.MustRegister(rpcDurations)
 	prometheus.MustRegister(rpcDurationsHistogram)
 	// Add Go module build info.
-	prometheus.MustRegister(prometheus.NewBuildInfoCollector())
+	prometheus.MustRegister(collectors.NewBuildInfoCollector())

 	start := time.Now()

--- a/go.mod
+++ b/go.mod
@ -3,13 +3,17 @@ module github.com/prometheus/client_golang
 require (
 	github.com/beorn7/perks v1.0.1
 	github.com/cespare/xxhash/v2 v2.1.2
+	github.com/davecgh/go-spew v1.1.1
 	github.com/golang/protobuf v1.5.2
+	github.com/jpillora/backoff v1.0.0 // indirect
 	github.com/json-iterator/go v1.1.12
 	github.com/prometheus/client_model v0.2.1-0.20210624201024-61b6c1aac064
-	github.com/prometheus/common v0.32.1
+	github.com/prometheus/common v0.34.0
 	github.com/prometheus/procfs v0.7.3
-	golang.org/x/sys v0.0.0-20220114195835-da31bd327af9
-	google.golang.org/protobuf v1.26.0
+	golang.org/x/sys v0.0.0-20220328115105-d36c6a25d886
+	google.golang.org/protobuf v1.28.0
 )

-go 1.13
+exclude github.com/prometheus/client_golang v1.12.1
+
+go 1.16
--- a/go.sum
+++ b/go.sum
@ -33,17 +33,9 @@ cloud.google.com/go/storage v1.10.0/go.mod h1:FLPqc6j+Ki4BU591ie1oL6qBQGu2Bl/tZ9
 dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
-github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
-github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
-github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
-github.com/alecthomas/units v0.0.0-20190717042225-c3de453c63f4/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
-github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d/go.mod h1:rBZYJk541a8SKzHPHnH3zbiI+7dagKZ0cgpgrD7Fyho=
-github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
-github.com/beorn7/perks v1.0.0/go.mod h1:KWe93zE9D1o94FZ5RNwFwVgaQK1VOXiVxmqh+CedLV8=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
-github.com/cespare/xxhash/v2 v2.1.1/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/cespare/xxhash/v2 v2.1.2 h1:YRXhKfTDauu4ajMg1TPgFO5jnlC2HCbmLXMcTG5cbYE=
 github.com/cespare/xxhash/v2 v2.1.2/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/chzyer/logex v1.1.10/go.mod h1:+Ywpsq7O8HXn0nuIou7OrIPyXbp3wmkHB+jjWRnGsAI=
@ -61,14 +53,8 @@ github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7
 github.com/go-gl/glfw v0.0.0-20190409004039-e6da0acd62b1/go.mod h1:vR7hzQXu2zJy9AVAgeJqvqgH9Q5CA+iKCZ2gyEVpxRU=
 github.com/go-gl/glfw/v3.3/glfw v0.0.0-20191125211704-12ad95a8df72/go.mod h1:tQ2UAYgL5IevRw8kRxooKSPJfGvJ9fJQFa0TUsXzTg8=
 github.com/go-gl/glfw/v3.3/glfw v0.0.0-20200222043503-6f7a984d4dc4/go.mod h1:tQ2UAYgL5IevRw8kRxooKSPJfGvJ9fJQFa0TUsXzTg8=
-github.com/go-kit/kit v0.8.0/go.mod h1:xBxKIO96dXMWWy0MnWVtmwkA9/13aqxPnvrjFYMA2as=
-github.com/go-kit/kit v0.9.0/go.mod h1:xBxKIO96dXMWWy0MnWVtmwkA9/13aqxPnvrjFYMA2as=
-github.com/go-kit/log v0.1.0/go.mod h1:zbhenjAZHb184qTLMA9ZjW7ThYL0H2mk7Q6pNt4vbaY=
-github.com/go-logfmt/logfmt v0.3.0/go.mod h1:Qt1PoO58o5twSAckw1HlFXLmHsOX5/0LbT9GBnD5lWE=
-github.com/go-logfmt/logfmt v0.4.0/go.mod h1:3RMwSq7FuexP4Kalkev3ejPJsZTpXXBr9+V4qmtdjCk=
-github.com/go-logfmt/logfmt v0.5.0/go.mod h1:wCYkCAKZfumFQihp8CzCvQ3paCTfi41vtzG1KdI/P7A=
-github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
-github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
+github.com/go-kit/log v0.2.0/go.mod h1:NwTd00d/i8cPZ3xOwwiv2PO5MOcx78fFErGNcVmBjv0=
+github.com/go-logfmt/logfmt v0.5.1/go.mod h1:WYhtIu8zTZfxdn5+rREduYbwxfcBr/Vr6KEVveWlfTs=
 github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
 github.com/golang/groupcache v0.0.0-20190702054246-869f871628b6/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
 github.com/golang/groupcache v0.0.0-20191227052852-215e87163ea7/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
@ -93,7 +79,6 @@ github.com/golang/protobuf v1.4.0-rc.4.0.20200313231945-b860323f09d0/go.mod h1:W
 github.com/golang/protobuf v1.4.0/go.mod h1:jodUvKwWbYaEsadDk5Fwe5c77LiNKVO9IDvqG2KuDX0=
 github.com/golang/protobuf v1.4.1/go.mod h1:U8fpvMrcmy5pZrNK1lt4xCsGvpyWQ/VVv6QDs8UjoX8=
 github.com/golang/protobuf v1.4.2/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
-github.com/golang/protobuf v1.4.3/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
 github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
 github.com/golang/protobuf v1.5.2 h1:ROPKBNFfQgOUMifHyP+KYbvpjbdoFNs+aK7DXlji0Tw=
 github.com/golang/protobuf v1.5.2/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
@ -127,19 +112,12 @@ github.com/hashicorp/golang-lru v0.5.1/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ
 github.com/ianlancetaylor/demangle v0.0.0-20181102032728-5e5cf60278f6/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
 github.com/jpillora/backoff v1.0.0 h1:uvFg412JmmHBHw7iwprIxkPMI+sGQ4kzOWsMeHnm2EA=
 github.com/jpillora/backoff v1.0.0/go.mod h1:J/6gKK9jxlEcS3zixgDgUAsiuZ7yrSoa/FX5e0EB2j4=
-github.com/json-iterator/go v1.1.6/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
-github.com/json-iterator/go v1.1.10/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
-github.com/json-iterator/go v1.1.11/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
 github.com/json-iterator/go v1.1.12 h1:PV8peI4a0ysnczrg+LtxykD8LfKY9ML6u2jnxaEnrnM=
 github.com/json-iterator/go v1.1.12/go.mod h1:e30LSqwooZae/UwlEbR2852Gd8hjQvJoHmT4TnhNGBo=
 github.com/jstemmer/go-junit-report v0.0.0-20190106144839-af01ea7f8024/go.mod h1:6v2b51hI/fHJwM22ozAgKL4VKDeJcHhJFhtBdhmNjmU=
 github.com/jstemmer/go-junit-report v0.9.1/go.mod h1:Brl9GWCQeLvo8nXZwPNNblvFj/XSXhF0NWZEnDohbsk=
-github.com/julienschmidt/httprouter v1.2.0/go.mod h1:SYymIcj16QtmaHHD7aYtjjsJG7VTCxuUUipMqKk8s4w=
 github.com/julienschmidt/httprouter v1.3.0/go.mod h1:JR6WtHb+2LUe8TCKY3cZOxFyyO8IZAc4RVcycCCAKdM=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
-github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
-github.com/konsorten/go-windows-terminal-sequences v1.0.3/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
-github.com/kr/logfmt v0.0.0-20140226030751-b84e30acd515/go.mod h1:+0opPa2QZZtGFBFZlji/RkVcI2GknAs/DXo4wKdlNEc=
 github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
@ -147,49 +125,24 @@ github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/matttproud/golang_protobuf_extensions v1.0.1 h1:4hp9jkHxhMHkqkrB3Ix0jegS5sx/RkqARlsWZ6pIwiU=
 github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5Ld7szi9bcBfOoFv/3dc6xSMkL2PC0=
+github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421 h1:ZqeYNhU3OHLH3mGKHDcjJRFFRrJa6eAM5H+CtDdOsPc=
 github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
-github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd h1:TRLaZ9cD/w8PVh93nsPXa1VrQ6jlwL5oN8l14QlcNfg=
-github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
-github.com/modern-go/reflect2 v0.0.0-20180701023420-4b7aa43c6742/go.mod h1:bx2lNnkwVCuqBIxFjflWJWanXIb3RllmbCylyMrvgv0=
-github.com/modern-go/reflect2 v1.0.1/go.mod h1:bx2lNnkwVCuqBIxFjflWJWanXIb3RllmbCylyMrvgv0=
 github.com/modern-go/reflect2 v1.0.2 h1:xBagoLtFs94CBntxluKeaWgTMpvLxC4ur3nMaC9Gz0M=
 github.com/modern-go/reflect2 v1.0.2/go.mod h1:yWuevngMOJpCy52FWWMvUC8ws7m/LJsjYzDa0/r8luk=
-github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
 github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f h1:KUppIJq7/+SVif2QVs3tOP0zanoHgBEVAwHxUSIzRqU=
 github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
-github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
-github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
-github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
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 github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
-github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPxbbu5VWo=
-github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
-github.com/sirupsen/logrus v1.6.0/go.mod h1:7uNnSEd1DgxDLC74fIahvMZmmYsHGZGEOFrfsX/uA88=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
@ -201,7 +154,6 @@ go.opencensus.io v0.22.0/go.mod h1:+kGneAE2xo2IficOXnaByMWTGM9T73dGwxeWcUqIpI8=
 go.opencensus.io v0.22.2/go.mod h1:yxeiOL68Rb0Xd1ddK5vPZ/oVn4vY4Ynel7k9FzqtOIw=
 go.opencensus.io v0.22.3/go.mod h1:yxeiOL68Rb0Xd1ddK5vPZ/oVn4vY4Ynel7k9FzqtOIw=
 go.opencensus.io v0.22.4/go.mod h1:yxeiOL68Rb0Xd1ddK5vPZ/oVn4vY4Ynel7k9FzqtOIw=
-golang.org/x/crypto v0.0.0-20180904163835-0709b304e793/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20190605123033-f99c8df09eb5/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
@ -239,7 +191,6 @@ golang.org/x/mod v0.2.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
-golang.org/x/net v0.0.0-20181114220301-adae6a3d119a/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190108225652-1e06a53dbb7e/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190213061140-3a22650c66bd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
@ -247,7 +198,6 @@ golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn
 golang.org/x/net v0.0.0-20190501004415-9ce7a6920f09/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190503192946-f4e77d36d62c/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190603091049-60506f45cf65/go.mod h1:HSz+uSET+XFnRR8LxR5pz3Of3rY3CfYBVs4xY44aLks=
-golang.org/x/net v0.0.0-20190613194153-d28f0bde5980/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20190628185345-da137c7871d7/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20190724013045-ca1201d0de80/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
@ -265,15 +215,16 @@ golang.org/x/net v0.0.0-20200520182314-0ba52f642ac2/go.mod h1:qpuaurCH72eLCgpAm/
 golang.org/x/net v0.0.0-20200625001655-4c5254603344/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
 golang.org/x/net v0.0.0-20200707034311-ab3426394381/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
 golang.org/x/net v0.0.0-20200822124328-c89045814202/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
-golang.org/x/net v0.0.0-20210525063256-abc453219eb5 h1:wjuX4b5yYQnEQHzd+CBcrcC6OVR2J1CN6mUy0oSxIPo=
-golang.org/x/net v0.0.0-20210525063256-abc453219eb5/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
+golang.org/x/net v0.0.0-20220127200216-cd36cc0744dd/go.mod h1:CfG3xpIq0wQ8r1q4Su4UZFWDARRcnwPjda9FqA0JpMk=
+golang.org/x/net v0.0.0-20220225172249-27dd8689420f h1:oA4XRj0qtSt8Yo1Zms0CUlsT3KG69V2UGQWPBxujDmc=
+golang.org/x/net v0.0.0-20220225172249-27dd8689420f/go.mod h1:CfG3xpIq0wQ8r1q4Su4UZFWDARRcnwPjda9FqA0JpMk=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.0.0-20191202225959-858c2ad4c8b6/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
-golang.org/x/oauth2 v0.0.0-20210514164344-f6687ab2804c h1:pkQiBZBvdos9qq4wBAHqlzuZHEXo07pqV06ef90u1WI=
-golang.org/x/oauth2 v0.0.0-20210514164344-f6687ab2804c/go.mod h1:KelEdhl1UZF7XfJ4dDtk6s++YSgaE7mD/BuKKDLBl4A=
+golang.org/x/oauth2 v0.0.0-20220223155221-ee480838109b h1:clP8eMhB30EHdc0bd2Twtq6kgU7yl5ub2cQLSdrv1Dg=
+golang.org/x/oauth2 v0.0.0-20220223155221-ee480838109b/go.mod h1:DAh4E804XQdzx2j+YRIaUnCqCV2RuMz24cGBJ5QYIrc=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@ -284,12 +235,9 @@ golang.org/x/sync v0.0.0-20200317015054-43a5402ce75a/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sync v0.0.0-20200625203802-6e8e738ad208/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20201207232520-09787c993a3a/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20181116152217-5ac8a444bdc5/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190312061237-fead79001313/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20190422165155-953cdadca894/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190502145724-3ef323f4f1fd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190507160741-ecd444e8653b/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190606165138-5da285871e9c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@ -298,7 +246,6 @@ golang.org/x/sys v0.0.0-20190726091711-fc99dfbffb4e/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20191001151750-bb3f8db39f24/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191204072324-ce4227a45e2e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191228213918-04cbcbbfeed8/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20200106162015-b016eb3dc98e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200113162924-86b910548bc1/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
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@ -311,23 +258,20 @@ golang.org/x/sys v0.0.0-20200501052902-10377860bb8e/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20200511232937-7e40ca221e25/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
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 golang.org/x/text v0.0.0-20170915032832-14c0d48ead0c/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.1-0.20180807135948-17ff2d5776d2/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/text v0.3.6 h1:aRYxNxv6iGQlyVaZmk6ZgYEDa+Jg18DxebPSrd6bg1M=
-golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/text v0.3.7 h1:olpwvP2KacW1ZWvsR7uQhoyTYvKAupfQrRGBFM352Gk=
+golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
 golang.org/x/time v0.0.0-20181108054448-85acf8d2951c/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/time v0.0.0-20190308202827-9d24e82272b4/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/time v0.0.0-20191024005414-555d28b269f0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
@ -451,19 +395,15 @@ google.golang.org/protobuf v1.23.1-0.20200526195155-81db48ad09cc/go.mod h1:EGpAD
 google.golang.org/protobuf v1.24.0/go.mod h1:r/3tXBNzIEhYS9I1OUVjXDlt8tc493IdKGjtUeSXeh4=
 google.golang.org/protobuf v1.25.0/go.mod h1:9JNX74DMeImyA3h4bdi1ymwjUzf21/xIlbajtzgsN7c=
 google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
-google.golang.org/protobuf v1.26.0 h1:bxAC2xTBsZGibn2RTntX0oH50xLsqy1OxA9tTL3p/lk=
 google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
+google.golang.org/protobuf v1.28.0 h1:w43yiav+6bVFTBQFZX0r7ipe9JQ1QsbMgHwbBziscLw=
+google.golang.org/protobuf v1.28.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=
 gopkg.in/alecthomas/kingpin.v2 v2.2.6/go.mod h1:FMv+mEhP44yOT+4EoQTLFTRgOQ1FBLkstjWtayDeSgw=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 h1:YR8cESwS4TdDjEe65xsg0ogRM/Nc3DYOhEAlW+xobZo=
-gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=
-gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
-gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
-gopkg.in/yaml.v2 v2.2.5/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
-gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
--- a/prometheus/collectors/collectors.go
+++ b/prometheus/collectors/collectors.go
@ -14,3 +14,27 @@
 // Package collectors provides implementations of prometheus.Collector to
 // conveniently collect process and Go-related metrics.
 package collectors
+
+import "github.com/prometheus/client_golang/prometheus"
+
+// NewBuildInfoCollector returns a collector collecting a single metric
+// "go_build_info" with the constant value 1 and three labels "path", "version",
+// and "checksum". Their label values contain the main module path, version, and
+// checksum, respectively. The labels will only have meaningful values if the
+// binary is built with Go module support and from source code retrieved from
+// the source repository (rather than the local file system). This is usually
+// accomplished by building from outside of GOPATH, specifying the full address
+// of the main package, e.g. "GO111MODULE=on go run
+// github.com/prometheus/client_golang/examples/random". If built without Go
+// module support, all label values will be "unknown". If built with Go module
+// support but using the source code from the local file system, the "path" will
+// be set appropriately, but "checksum" will be empty and "version" will be
+// "(devel)".
+//
+// This collector uses only the build information for the main module. See
+// https://github.com/povilasv/prommod for an example of a collector for the
+// module dependencies.
+func NewBuildInfoCollector() prometheus.Collector {
+	//nolint:staticcheck // Ignore SA1019 until v2.
+	return prometheus.NewBuildInfoCollector()
+}
--- a/prometheus/collectors/dbstats_collector.go
+++ b/prometheus/collectors/dbstats_collector.go
@ -101,7 +101,7 @@ func (c *dbStatsCollector) Describe(ch chan<- *prometheus.Desc) {
 	ch <- c.waitDuration
 	ch <- c.maxIdleClosed
 	ch <- c.maxLifetimeClosed
-	c.describeNewInGo115(ch)
+	ch <- c.maxIdleTimeClosed
 }

 // Collect implements Collector.
@ -115,5 +115,5 @@ func (c *dbStatsCollector) Collect(ch chan<- prometheus.Metric) {
 	ch <- prometheus.MustNewConstMetric(c.waitDuration, prometheus.CounterValue, stats.WaitDuration.Seconds())
 	ch <- prometheus.MustNewConstMetric(c.maxIdleClosed, prometheus.CounterValue, float64(stats.MaxIdleClosed))
 	ch <- prometheus.MustNewConstMetric(c.maxLifetimeClosed, prometheus.CounterValue, float64(stats.MaxLifetimeClosed))
-	c.collectNewInGo115(ch, stats)
+	ch <- prometheus.MustNewConstMetric(c.maxIdleTimeClosed, prometheus.CounterValue, float64(stats.MaxIdleTimeClosed))
 }
--- a/prometheus/collectors/dbstats_collector_pre_go115.go
+++ b/prometheus/collectors/dbstats_collector_pre_go115.go
@ -1,27 +0,0 @@
-// Copyright 2021 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-//go:build !go1.15
-// +build !go1.15
-
-package collectors
-
-import (
-	"database/sql"
-
-	"github.com/prometheus/client_golang/prometheus"
-)
-
-func (c *dbStatsCollector) describeNewInGo115(ch chan<- *prometheus.Desc) {}
-
-func (c *dbStatsCollector) collectNewInGo115(ch chan<- prometheus.Metric, stats sql.DBStats) {}
--- a/prometheus/collectors/dbstats_collector_test.go
+++ b/prometheus/collectors/dbstats_collector_test.go
@ -15,7 +15,6 @@ package collectors

 import (
 	"database/sql"
-	"runtime"
 	"testing"

 	"github.com/prometheus/client_golang/prometheus"
@ -50,9 +49,7 @@ func TestDBStatsCollector(t *testing.T) {
 		"go_sql_wait_duration_seconds_total",
 		"go_sql_max_idle_closed_total",
 		"go_sql_max_lifetime_closed_total",
-	}
-	if runtime.Version() >= "go1.15" {
-		names = append(names, "go_sql_max_idle_time_closed_total")
+		"go_sql_max_idle_time_closed_total",
 	}
 	type result struct {
 		found bool
--- a/prometheus/collectors/go_collector_go116.go
+++ b/prometheus/collectors/go_collector_go116.go
@ -11,6 +11,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.

+//go:build !go1.17
+// +build !go1.17
+
 package collectors

 import "github.com/prometheus/client_golang/prometheus"
@ -42,28 +45,5 @@ import "github.com/prometheus/client_golang/prometheus"
 // NOTE: The problem is solved in Go 1.15, see
 // https://github.com/golang/go/issues/19812 for the related Go issue.
 func NewGoCollector() prometheus.Collector {
-	//nolint:staticcheck // Ignore SA1019 until v2.
 	return prometheus.NewGoCollector()
 }
-
-// NewBuildInfoCollector returns a collector collecting a single metric
-// "go_build_info" with the constant value 1 and three labels "path", "version",
-// and "checksum". Their label values contain the main module path, version, and
-// checksum, respectively. The labels will only have meaningful values if the
-// binary is built with Go module support and from source code retrieved from
-// the source repository (rather than the local file system). This is usually
-// accomplished by building from outside of GOPATH, specifying the full address
-// of the main package, e.g. "GO111MODULE=on go run
-// github.com/prometheus/client_golang/examples/random". If built without Go
-// module support, all label values will be "unknown". If built with Go module
-// support but using the source code from the local file system, the "path" will
-// be set appropriately, but "checksum" will be empty and "version" will be
-// "(devel)".
-//
-// This collector uses only the build information for the main module. See
-// https://github.com/povilasv/prommod for an example of a collector for the
-// module dependencies.
-func NewBuildInfoCollector() prometheus.Collector {
-	//nolint:staticcheck // Ignore SA1019 until v2.
-	return prometheus.NewBuildInfoCollector()
-}
--- a/prometheus/collectors/go_collector_latest.go
+++ b/prometheus/collectors/go_collector_latest.go
@ -0,0 +1,91 @@
+// Copyright 2021 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build go1.17
+// +build go1.17
+
+package collectors
+
+import "github.com/prometheus/client_golang/prometheus"
+
+//nolint:staticcheck // Ignore SA1019 until v2.
+type goOptions = prometheus.GoCollectorOptions
+type goOption func(o *goOptions)
+
+type GoCollectionOption uint32
+
+const (
+	// GoRuntimeMemStatsCollection represents the metrics represented by runtime.MemStats structure such as
+	// go_memstats_alloc_bytes
+	// go_memstats_alloc_bytes_total
+	// go_memstats_sys_bytes
+	// go_memstats_lookups_total
+	// go_memstats_mallocs_total
+	// go_memstats_frees_total
+	// go_memstats_heap_alloc_bytes
+	// go_memstats_heap_sys_bytes
+	// go_memstats_heap_idle_bytes
+	// go_memstats_heap_inuse_bytes
+	// go_memstats_heap_released_bytes
+	// go_memstats_heap_objects
+	// go_memstats_stack_inuse_bytes
+	// go_memstats_stack_sys_bytes
+	// go_memstats_mspan_inuse_bytes
+	// go_memstats_mspan_sys_bytes
+	// go_memstats_mcache_inuse_bytes
+	// go_memstats_mcache_sys_bytes
+	// go_memstats_buck_hash_sys_bytes
+	// go_memstats_gc_sys_bytes
+	// go_memstats_other_sys_bytes
+	// go_memstats_next_gc_bytes
+	// so the metrics known from pre client_golang v1.12.0, except skipped go_memstats_gc_cpu_fraction (see
+	// https://github.com/prometheus/client_golang/issues/842#issuecomment-861812034 for explanation.
+	//
+	// NOTE that this mode represents runtime.MemStats statistics, but they are
+	// actually implemented using new runtime/metrics package.
+	// Deprecated: Use GoRuntimeMetricsCollection instead going forward.
+	GoRuntimeMemStatsCollection GoCollectionOption = 1 << iota
+	// GoRuntimeMetricsCollection is the new set of metrics represented by runtime/metrics package and follows
+	// consistent naming. The exposed metric set depends on Go version, but it is controlled against
+	// unexpected cardinality. This set has overlapping information with GoRuntimeMemStatsCollection, just with
+	// new names. GoRuntimeMetricsCollection is what is recommended for using going forward.
+	GoRuntimeMetricsCollection
+)
+
+// WithGoCollections allows enabling different collections for Go collector on top of base metrics
+// like go_goroutines, go_threads, go_gc_duration_seconds, go_memstats_last_gc_time_seconds, go_info.
+//
+// Check GoRuntimeMemStatsCollection and GoRuntimeMetricsCollection for more details. You can use none,
+// one or more collections at once. For example:
+// WithGoCollections(GoRuntimeMemStatsCollection | GoRuntimeMetricsCollection) means both GoRuntimeMemStatsCollection
+// metrics and GoRuntimeMetricsCollection will be exposed.
+//
+// The current default is GoRuntimeMemStatsCollection, so the compatibility mode with
+// client_golang pre v1.12 (move to runtime/metrics).
+func WithGoCollections(flags GoCollectionOption) goOption {
+	return func(o *goOptions) {
+		o.EnabledCollections = uint32(flags)
+	}
+}
+
+// NewGoCollector returns a collector that exports metrics about the current Go
+// process using debug.GCStats using runtime/metrics.
+func NewGoCollector(opts ...goOption) prometheus.Collector {
+	//nolint:staticcheck // Ignore SA1019 until v2.
+	promPkgOpts := make([]func(o *prometheus.GoCollectorOptions), len(opts))
+	for i, opt := range opts {
+		promPkgOpts[i] = opt
+	}
+	//nolint:staticcheck // Ignore SA1019 until v2.
+	return prometheus.NewGoCollector(promPkgOpts...)
+}
--- a/prometheus/collectors/go_collector_latest_test.go
+++ b/prometheus/collectors/go_collector_latest_test.go
@ -11,21 +11,29 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.

-//go:build go1.15
-// +build go1.15
+//go:build go1.17
+// +build go1.17

 package collectors

 import (
-	"database/sql"
+	"encoding/json"
+	"testing"

 	"github.com/prometheus/client_golang/prometheus"
 )

-func (c *dbStatsCollector) describeNewInGo115(ch chan<- *prometheus.Desc) {
-	ch <- c.maxIdleTimeClosed
-}
+func TestGoCollectorMarshalling(t *testing.T) {
+	reg := prometheus.NewRegistry()
+	reg.MustRegister(NewGoCollector(
+		WithGoCollections(GoRuntimeMemStatsCollection | GoRuntimeMetricsCollection),
+	))
+	result, err := reg.Gather()
+	if err != nil {
+		t.Fatal(err)
+	}

-func (c *dbStatsCollector) collectNewInGo115(ch chan<- prometheus.Metric, stats sql.DBStats) {
-	ch <- prometheus.MustNewConstMetric(c.maxIdleTimeClosed, prometheus.CounterValue, float64(stats.MaxIdleTimeClosed))
+	if _, err := json.Marshal(result); err != nil {
+		t.Errorf("json marshalling shoud not fail, %v", err)
+	}
 }
--- a/prometheus/desc.go
+++ b/prometheus/desc.go
@ -20,6 +20,8 @@ import (
 	"strings"

 	"github.com/cespare/xxhash/v2"
+	"github.com/prometheus/client_golang/prometheus/internal"
+
 	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
 	"github.com/golang/protobuf/proto"
 	"github.com/prometheus/common/model"
@ -154,7 +156,7 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 			Value: proto.String(v),
 		})
 	}
-	sort.Sort(labelPairSorter(d.constLabelPairs))
+	sort.Sort(internal.LabelPairSorter(d.constLabelPairs))
 	return d
 }

--- a/prometheus/examples_test.go
+++ b/prometheus/examples_test.go
@ -24,9 +24,8 @@ import (

 	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
 	"github.com/golang/protobuf/proto"
-	"github.com/prometheus/common/expfmt"
-
 	dto "github.com/prometheus/client_model/go"
+	"github.com/prometheus/common/expfmt"

 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
@ -599,6 +598,115 @@ func ExampleNewConstHistogram() {
 	// >
 }

+func ExampleNewConstHistogram_WithExemplar() {
+	desc := prometheus.NewDesc(
+		"http_request_duration_seconds",
+		"A histogram of the HTTP request durations.",
+		[]string{"code", "method"},
+		prometheus.Labels{"owner": "example"},
+	)
+
+	// Create a constant histogram from values we got from a 3rd party telemetry system.
+	h := prometheus.MustNewConstHistogram(
+		desc,
+		4711, 403.34,
+		map[float64]uint64{25: 121, 50: 2403, 100: 3221, 200: 4233},
+		"200", "get",
+	)
+
+	// Wrap const histogram with exemplars for each bucket.
+	exemplarTs, _ := time.Parse(time.RFC850, "Monday, 02-Jan-06 15:04:05 GMT")
+	exemplarLabels := prometheus.Labels{"testName": "testVal"}
+	h = prometheus.MustNewMetricWithExemplars(
+		h,
+		prometheus.Exemplar{Labels: exemplarLabels, Timestamp: exemplarTs, Value: 24.0},
+		prometheus.Exemplar{Labels: exemplarLabels, Timestamp: exemplarTs, Value: 42.0},
+		prometheus.Exemplar{Labels: exemplarLabels, Timestamp: exemplarTs, Value: 89.0},
+		prometheus.Exemplar{Labels: exemplarLabels, Timestamp: exemplarTs, Value: 157.0},
+	)
+
+	// Just for demonstration, let's check the state of the histogram by
+	// (ab)using its Write method (which is usually only used by Prometheus
+	// internally).
+	metric := &dto.Metric{}
+	h.Write(metric)
+	fmt.Println(proto.MarshalTextString(metric))
+
+	// Output:
+	// label: <
+	//   name: "code"
+	//   value: "200"
+	// >
+	// label: <
+	//   name: "method"
+	//   value: "get"
+	// >
+	// label: <
+	//   name: "owner"
+	//   value: "example"
+	// >
+	// histogram: <
+	//   sample_count: 4711
+	//   sample_sum: 403.34
+	//   bucket: <
+	//     cumulative_count: 121
+	//     upper_bound: 25
+	//     exemplar: <
+	//       label: <
+	//         name: "testName"
+	//         value: "testVal"
+	//       >
+	//       value: 24
+	//       timestamp: <
+	//         seconds: 1136214245
+	//       >
+	//     >
+	//   >
+	//   bucket: <
+	//     cumulative_count: 2403
+	//     upper_bound: 50
+	//     exemplar: <
+	//       label: <
+	//         name: "testName"
+	//         value: "testVal"
+	//       >
+	//       value: 42
+	//       timestamp: <
+	//         seconds: 1136214245
+	//       >
+	//     >
+	//   >
+	//   bucket: <
+	//     cumulative_count: 3221
+	//     upper_bound: 100
+	//     exemplar: <
+	//       label: <
+	//         name: "testName"
+	//         value: "testVal"
+	//       >
+	//       value: 89
+	//       timestamp: <
+	//         seconds: 1136214245
+	//       >
+	//     >
+	//   >
+	//   bucket: <
+	//     cumulative_count: 4233
+	//     upper_bound: 200
+	//     exemplar: <
+	//       label: <
+	//         name: "testName"
+	//         value: "testVal"
+	//       >
+	//       value: 157
+	//       timestamp: <
+	//         seconds: 1136214245
+	//       >
+	//     >
+	//   >
+	// >
+}
+
 func ExampleAlreadyRegisteredError() {
 	reqCounter := prometheus.NewCounter(prometheus.CounterOpts{
 		Name: "requests_total",
--- a/prometheus/gen_go_collector_metrics_set.go
+++ b/prometheus/gen_go_collector_metrics_set.go
@ -38,10 +38,12 @@ func main() {
 		log.Fatal("requires Go version (e.g. go1.17) as an argument")
 	}
 	toolVersion := runtime.Version()
-	if majorVersion := toolVersion[:strings.LastIndexByte(toolVersion, '.')]; majorVersion != os.Args[1] {
-		log.Fatalf("using Go version %q but expected Go version %q", majorVersion, os.Args[1])
+	mtv := majorVersion(toolVersion)
+	mv := majorVersion(os.Args[1])
+	if mtv != mv {
+		log.Fatalf("using Go version %q but expected Go version %q", mtv, mv)
 	}
-	version, err := parseVersion(os.Args[1])
+	version, err := parseVersion(mv)
 	if err != nil {
 		log.Fatalf("parsing Go version: %v", err)
 	}
@ -93,6 +95,10 @@ func parseVersion(s string) (goVersion, error) {
 	return goVersion(i), err
 }

+func majorVersion(v string) string {
+	return v[:strings.LastIndexByte(v, '.')]
+}
+
 func rmCardinality() int {
 	cardinality := 0

--- a/prometheus/go_collector.go
+++ b/prometheus/go_collector.go
@ -197,14 +197,6 @@ func goRuntimeMemStats() memStatsMetrics {
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.NextGC) },
 			valType: GaugeValue,
-		}, {
-			desc: NewDesc(
-				memstatNamespace("gc_cpu_fraction"),
-				"The fraction of this program's available CPU time used by the GC since the program started.",
-				nil, nil,
-			),
-			eval:    func(ms *runtime.MemStats) float64 { return ms.GCCPUFraction },
-			valType: GaugeValue,
 		},
 	}
 }
@ -268,7 +260,6 @@ func (c *baseGoCollector) Collect(ch chan<- Metric) {
 	quantiles[0.0] = stats.PauseQuantiles[0].Seconds()
 	ch <- MustNewConstSummary(c.gcDesc, uint64(stats.NumGC), stats.PauseTotal.Seconds(), quantiles)
 	ch <- MustNewConstMetric(c.gcLastTimeDesc, GaugeValue, float64(stats.LastGC.UnixNano())/1e9)
-
 	ch <- MustNewConstMetric(c.goInfoDesc, GaugeValue, 1)
 }

@ -278,6 +269,7 @@ func memstatNamespace(s string) string {

 // memStatsMetrics provide description, evaluator, runtime/metrics name, and
 // value type for memstat metrics.
+// TODO(bwplotka): Remove with end Go 1.16 EOL and replace with runtime/metrics.Description
 type memStatsMetrics []struct {
 	desc    *Desc
 	eval    func(*runtime.MemStats) float64
--- a/prometheus/go_collector_go116.go
+++ b/prometheus/go_collector_go116.go
@ -40,13 +40,28 @@ type goCollector struct {
 //
 // Deprecated: Use collectors.NewGoCollector instead.
 func NewGoCollector() Collector {
+	msMetrics := goRuntimeMemStats()
+	msMetrics = append(msMetrics, struct {
+		desc    *Desc
+		eval    func(*runtime.MemStats) float64
+		valType ValueType
+	}{
+		// This metric is omitted in Go1.17+, see https://github.com/prometheus/client_golang/issues/842#issuecomment-861812034
+		desc: NewDesc(
+			memstatNamespace("gc_cpu_fraction"),
+			"The fraction of this program's available CPU time used by the GC since the program started.",
+			nil, nil,
+		),
+		eval:    func(ms *runtime.MemStats) float64 { return ms.GCCPUFraction },
+		valType: GaugeValue,
+	})
 	return &goCollector{
 		base:      newBaseGoCollector(),
 		msLast:    &runtime.MemStats{},
 		msRead:    runtime.ReadMemStats,
 		msMaxWait: time.Second,
 		msMaxAge:  5 * time.Minute,
-		msMetrics: goRuntimeMemStats(),
+		msMetrics: msMetrics,
 	}
 }

--- a/prometheus/go_collector_latest.go
+++ b/prometheus/go_collector_latest.go
@ -25,11 +25,71 @@ import (

 	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
 	"github.com/golang/protobuf/proto"
-	"github.com/prometheus/client_golang/prometheus/internal"
 	dto "github.com/prometheus/client_model/go"
+
+	"github.com/prometheus/client_golang/prometheus/internal"
 )

+const (
+	goGCHeapTinyAllocsObjects               = "/gc/heap/tiny/allocs:objects"
+	goGCHeapAllocsObjects                   = "/gc/heap/allocs:objects"
+	goGCHeapFreesObjects                    = "/gc/heap/frees:objects"
+	goGCHeapAllocsBytes                     = "/gc/heap/allocs:bytes"
+	goGCHeapObjects                         = "/gc/heap/objects:objects"
+	goGCHeapGoalBytes                       = "/gc/heap/goal:bytes"
+	goMemoryClassesTotalBytes               = "/memory/classes/total:bytes"
+	goMemoryClassesHeapObjectsBytes         = "/memory/classes/heap/objects:bytes"
+	goMemoryClassesHeapUnusedBytes          = "/memory/classes/heap/unused:bytes"
+	goMemoryClassesHeapReleasedBytes        = "/memory/classes/heap/released:bytes"
+	goMemoryClassesHeapFreeBytes            = "/memory/classes/heap/free:bytes"
+	goMemoryClassesHeapStacksBytes          = "/memory/classes/heap/stacks:bytes"
+	goMemoryClassesOSStacksBytes            = "/memory/classes/os-stacks:bytes"
+	goMemoryClassesMetadataMSpanInuseBytes  = "/memory/classes/metadata/mspan/inuse:bytes"
+	goMemoryClassesMetadataMSPanFreeBytes   = "/memory/classes/metadata/mspan/free:bytes"
+	goMemoryClassesMetadataMCacheInuseBytes = "/memory/classes/metadata/mcache/inuse:bytes"
+	goMemoryClassesMetadataMCacheFreeBytes  = "/memory/classes/metadata/mcache/free:bytes"
+	goMemoryClassesProfilingBucketsBytes    = "/memory/classes/profiling/buckets:bytes"
+	goMemoryClassesMetadataOtherBytes       = "/memory/classes/metadata/other:bytes"
+	goMemoryClassesOtherBytes               = "/memory/classes/other:bytes"
+)
+
+// runtime/metrics names required for runtimeMemStats like logic.
+var rmForMemStats = []string{goGCHeapTinyAllocsObjects,
+	goGCHeapAllocsObjects,
+	goGCHeapFreesObjects,
+	goGCHeapAllocsBytes,
+	goGCHeapObjects,
+	goGCHeapGoalBytes,
+	goMemoryClassesTotalBytes,
+	goMemoryClassesHeapObjectsBytes,
+	goMemoryClassesHeapUnusedBytes,
+	goMemoryClassesHeapReleasedBytes,
+	goMemoryClassesHeapFreeBytes,
+	goMemoryClassesHeapStacksBytes,
+	goMemoryClassesOSStacksBytes,
+	goMemoryClassesMetadataMSpanInuseBytes,
+	goMemoryClassesMetadataMSPanFreeBytes,
+	goMemoryClassesMetadataMCacheInuseBytes,
+	goMemoryClassesMetadataMCacheFreeBytes,
+	goMemoryClassesProfilingBucketsBytes,
+	goMemoryClassesMetadataOtherBytes,
+	goMemoryClassesOtherBytes,
+}
+
+func bestEffortLookupRM(lookup []string) []metrics.Description {
+	ret := make([]metrics.Description, 0, len(lookup))
+	for _, rm := range metrics.All() {
+		for _, m := range lookup {
+			if m == rm.Name {
+				ret = append(ret, rm)
+			}
+		}
+	}
+	return ret
+}
+
 type goCollector struct {
+	opt  GoCollectorOptions
 	base baseGoCollector

 	// mu protects updates to all fields ensuring a consistent
@ -51,12 +111,46 @@ type goCollector struct {
 	msMetrics memStatsMetrics
 }

+const (
+	// Those are not exposed due to need to move Go collector to another package in v2.
+	// See issue https://github.com/prometheus/client_golang/issues/1030.
+	goRuntimeMemStatsCollection uint32 = 1 << iota
+	goRuntimeMetricsCollection
+)
+
+// GoCollectorOptions should not be used be directly by anything, except `collectors` package.
+// Use it via collectors package instead. See issue
+// https://github.com/prometheus/client_golang/issues/1030.
+//
+// Deprecated: Use collectors.WithGoCollections
+type GoCollectorOptions struct {
+	// EnabledCollection sets what type of collections collector should expose on top of base collection.
+	// By default it's goMemStatsCollection | goRuntimeMetricsCollection.
+	EnabledCollections uint32
+}
+
+func (c GoCollectorOptions) isEnabled(flag uint32) bool {
+	return c.EnabledCollections&flag != 0
+}
+
+const defaultGoCollections = goRuntimeMemStatsCollection
+
 // NewGoCollector is the obsolete version of collectors.NewGoCollector.
 // See there for documentation.
 //
 // Deprecated: Use collectors.NewGoCollector instead.
-func NewGoCollector() Collector {
-	descriptions := metrics.All()
+func NewGoCollector(opts ...func(o *GoCollectorOptions)) Collector {
+	opt := GoCollectorOptions{EnabledCollections: defaultGoCollections}
+	for _, o := range opts {
+		o(&opt)
+	}
+
+	var descriptions []metrics.Description
+	if opt.isEnabled(goRuntimeMetricsCollection) {
+		descriptions = metrics.All()
+	} else if opt.isEnabled(goRuntimeMemStatsCollection) {
+		descriptions = bestEffortLookupRM(rmForMemStats)
+	}

 	// Collect all histogram samples so that we can get their buckets.
 	// The API guarantees that the buckets are always fixed for the lifetime
@ -67,7 +161,11 @@ func NewGoCollector() Collector {
 			histograms = append(histograms, metrics.Sample{Name: d.Name})
 		}
 	}
-	metrics.Read(histograms)
+
+	if len(histograms) > 0 {
+		metrics.Read(histograms)
+	}
+
 	bucketsMap := make(map[string][]float64)
 	for i := range histograms {
 		bucketsMap[histograms[i].Name] = histograms[i].Value.Float64Histogram().Buckets
@ -83,7 +181,7 @@ func NewGoCollector() Collector {
 		if !ok {
 			// Just ignore this metric; we can't do anything with it here.
 			// If a user decides to use the latest version of Go, we don't want
-			// to fail here. This condition is tested elsewhere.
+			// to fail here. This condition is tested in TestExpectedRuntimeMetrics.
 			continue
 		}

@ -123,12 +221,18 @@ func NewGoCollector() Collector {
 		}
 		metricSet = append(metricSet, m)
 	}
+
+	var msMetrics memStatsMetrics
+	if opt.isEnabled(goRuntimeMemStatsCollection) {
+		msMetrics = goRuntimeMemStats()
+	}
 	return &goCollector{
+		opt:         opt,
 		base:        newBaseGoCollector(),
 		rmSampleBuf: sampleBuf,
 		rmSampleMap: sampleMap,
 		rmMetrics:   metricSet,
-		msMetrics:   goRuntimeMemStats(),
+		msMetrics:   msMetrics,
 	}
 }

@ -163,40 +267,47 @@ func (c *goCollector) Collect(ch chan<- Metric) {
 	c.mu.Lock()
 	defer c.mu.Unlock()

-	// Populate runtime/metrics sample buffer.
-	metrics.Read(c.rmSampleBuf)
+	if len(c.rmSampleBuf) > 0 {
+		// Populate runtime/metrics sample buffer.
+		metrics.Read(c.rmSampleBuf)
+	}

-	// Update all our metrics from rmSampleBuf.
-	for i, sample := range c.rmSampleBuf {
-		// N.B. switch on concrete type because it's significantly more efficient
-		// than checking for the Counter and Gauge interface implementations. In
-		// this case, we control all the types here.
-		switch m := c.rmMetrics[i].(type) {
-		case *counter:
-			// Guard against decreases. This should never happen, but a failure
-			// to do so will result in a panic, which is a harsh consequence for
-			// a metrics collection bug.
-			v0, v1 := m.get(), unwrapScalarRMValue(sample.Value)
-			if v1 > v0 {
-				m.Add(unwrapScalarRMValue(sample.Value) - m.get())
+	if c.opt.isEnabled(goRuntimeMetricsCollection) {
+		// Collect all our metrics from rmSampleBuf.
+		for i, sample := range c.rmSampleBuf {
+			// N.B. switch on concrete type because it's significantly more efficient
+			// than checking for the Counter and Gauge interface implementations. In
+			// this case, we control all the types here.
+			switch m := c.rmMetrics[i].(type) {
+			case *counter:
+				// Guard against decreases. This should never happen, but a failure
+				// to do so will result in a panic, which is a harsh consequence for
+				// a metrics collection bug.
+				v0, v1 := m.get(), unwrapScalarRMValue(sample.Value)
+				if v1 > v0 {
+					m.Add(unwrapScalarRMValue(sample.Value) - m.get())
+				}
+				m.Collect(ch)
+			case *gauge:
+				m.Set(unwrapScalarRMValue(sample.Value))
+				m.Collect(ch)
+			case *batchHistogram:
+				m.update(sample.Value.Float64Histogram(), c.exactSumFor(sample.Name))
+				m.Collect(ch)
+			default:
+				panic("unexpected metric type")
 			}
-			m.Collect(ch)
-		case *gauge:
-			m.Set(unwrapScalarRMValue(sample.Value))
-			m.Collect(ch)
-		case *batchHistogram:
-			m.update(sample.Value.Float64Histogram(), c.exactSumFor(sample.Name))
-			m.Collect(ch)
-		default:
-			panic("unexpected metric type")
 		}
 	}
+
 	// ms is a dummy MemStats that we populate ourselves so that we can
-	// populate the old metrics from it.
-	var ms runtime.MemStats
-	memStatsFromRM(&ms, c.rmSampleMap)
-	for _, i := range c.msMetrics {
-		ch <- MustNewConstMetric(i.desc, i.valType, i.eval(&ms))
+	// populate the old metrics from it if goMemStatsCollection is enabled.
+	if c.opt.isEnabled(goRuntimeMemStatsCollection) {
+		var ms runtime.MemStats
+		memStatsFromRM(&ms, c.rmSampleMap)
+		for _, i := range c.msMetrics {
+			ch <- MustNewConstMetric(i.desc, i.valType, i.eval(&ms))
+		}
 	}
 }

@ -261,35 +372,30 @@ func memStatsFromRM(ms *runtime.MemStats, rm map[string]*metrics.Sample) {
 	// while having Mallocs - Frees still represent a live object count.
 	// Unfortunately, MemStats doesn't actually export a large allocation count,
 	// so it's impossible to pull this number out directly.
-	tinyAllocs := lookupOrZero("/gc/heap/tiny/allocs:objects")
-	ms.Mallocs = lookupOrZero("/gc/heap/allocs:objects") + tinyAllocs
-	ms.Frees = lookupOrZero("/gc/heap/frees:objects") + tinyAllocs
+	tinyAllocs := lookupOrZero(goGCHeapTinyAllocsObjects)
+	ms.Mallocs = lookupOrZero(goGCHeapAllocsObjects) + tinyAllocs
+	ms.Frees = lookupOrZero(goGCHeapFreesObjects) + tinyAllocs

-	ms.TotalAlloc = lookupOrZero("/gc/heap/allocs:bytes")
-	ms.Sys = lookupOrZero("/memory/classes/total:bytes")
+	ms.TotalAlloc = lookupOrZero(goGCHeapAllocsBytes)
+	ms.Sys = lookupOrZero(goMemoryClassesTotalBytes)
 	ms.Lookups = 0 // Already always zero.
-	ms.HeapAlloc = lookupOrZero("/memory/classes/heap/objects:bytes")
+	ms.HeapAlloc = lookupOrZero(goMemoryClassesHeapObjectsBytes)
 	ms.Alloc = ms.HeapAlloc
-	ms.HeapInuse = ms.HeapAlloc + lookupOrZero("/memory/classes/heap/unused:bytes")
-	ms.HeapReleased = lookupOrZero("/memory/classes/heap/released:bytes")
-	ms.HeapIdle = ms.HeapReleased + lookupOrZero("/memory/classes/heap/free:bytes")
+	ms.HeapInuse = ms.HeapAlloc + lookupOrZero(goMemoryClassesHeapUnusedBytes)
+	ms.HeapReleased = lookupOrZero(goMemoryClassesHeapReleasedBytes)
+	ms.HeapIdle = ms.HeapReleased + lookupOrZero(goMemoryClassesHeapFreeBytes)
 	ms.HeapSys = ms.HeapInuse + ms.HeapIdle
-	ms.HeapObjects = lookupOrZero("/gc/heap/objects:objects")
-	ms.StackInuse = lookupOrZero("/memory/classes/heap/stacks:bytes")
-	ms.StackSys = ms.StackInuse + lookupOrZero("/memory/classes/os-stacks:bytes")
-	ms.MSpanInuse = lookupOrZero("/memory/classes/metadata/mspan/inuse:bytes")
-	ms.MSpanSys = ms.MSpanInuse + lookupOrZero("/memory/classes/metadata/mspan/free:bytes")
-	ms.MCacheInuse = lookupOrZero("/memory/classes/metadata/mcache/inuse:bytes")
-	ms.MCacheSys = ms.MCacheInuse + lookupOrZero("/memory/classes/metadata/mcache/free:bytes")
-	ms.BuckHashSys = lookupOrZero("/memory/classes/profiling/buckets:bytes")
-	ms.GCSys = lookupOrZero("/memory/classes/metadata/other:bytes")
-	ms.OtherSys = lookupOrZero("/memory/classes/other:bytes")
-	ms.NextGC = lookupOrZero("/gc/heap/goal:bytes")
-
-	// N.B. LastGC is omitted because runtime.GCStats already has this.
-	// See https://github.com/prometheus/client_golang/issues/842#issuecomment-861812034
-	// for more details.
-	ms.LastGC = 0
+	ms.HeapObjects = lookupOrZero(goGCHeapObjects)
+	ms.StackInuse = lookupOrZero(goMemoryClassesHeapStacksBytes)
+	ms.StackSys = ms.StackInuse + lookupOrZero(goMemoryClassesOSStacksBytes)
+	ms.MSpanInuse = lookupOrZero(goMemoryClassesMetadataMSpanInuseBytes)
+	ms.MSpanSys = ms.MSpanInuse + lookupOrZero(goMemoryClassesMetadataMSPanFreeBytes)
+	ms.MCacheInuse = lookupOrZero(goMemoryClassesMetadataMCacheInuseBytes)
+	ms.MCacheSys = ms.MCacheInuse + lookupOrZero(goMemoryClassesMetadataMCacheFreeBytes)
+	ms.BuckHashSys = lookupOrZero(goMemoryClassesProfilingBucketsBytes)
+	ms.GCSys = lookupOrZero(goMemoryClassesMetadataOtherBytes)
+	ms.OtherSys = lookupOrZero(goMemoryClassesOtherBytes)
+	ms.NextGC = lookupOrZero(goGCHeapGoalBytes)

 	// N.B. GCCPUFraction is intentionally omitted. This metric is not useful,
 	// and often misleading due to the fact that it's an average over the lifetime
@ -324,6 +430,11 @@ type batchHistogram struct {
 // buckets must always be from the runtime/metrics package, following
 // the same conventions.
 func newBatchHistogram(desc *Desc, buckets []float64, hasSum bool) *batchHistogram {
+	// We need to remove -Inf values. runtime/metrics keeps them around.
+	// But -Inf bucket should not be allowed for prometheus histograms.
+	if buckets[0] == math.Inf(-1) {
+		buckets = buckets[1:]
+	}
 	h := &batchHistogram{
 		desc:    desc,
 		buckets: buckets,
@ -382,8 +493,10 @@ func (h *batchHistogram) Write(out *dto.Metric) error {
 	for i, count := range h.counts {
 		totalCount += count
 		if !h.hasSum {
-			// N.B. This computed sum is an underestimate.
-			sum += h.buckets[i] * float64(count)
+			if count != 0 {
+				// N.B. This computed sum is an underestimate.
+				sum += h.buckets[i] * float64(count)
+			}
 		}

 		// Skip the +Inf bucket, but only for the bucket list.
--- a/prometheus/go_collector_latest_test.go
+++ b/prometheus/go_collector_latest_test.go
@ -24,86 +24,105 @@ import (
 	"sync"
 	"testing"

-	"github.com/prometheus/client_golang/prometheus/internal"
 	dto "github.com/prometheus/client_model/go"
+
+	"github.com/prometheus/client_golang/prometheus/internal"
 )

-func TestGoCollectorRuntimeMetrics(t *testing.T) {
-	metrics := collectGoMetrics(t)
-
-	msChecklist := make(map[string]bool)
-	for _, m := range goRuntimeMemStats() {
-		msChecklist[m.desc.fqName] = false
-	}
-
-	if len(metrics) == 0 {
-		t.Fatal("no metrics created by Collect")
-	}
-
-	// Check a few specific metrics.
-	//
-	// Checking them all is somewhat pointless because the runtime/metrics
-	// metrics are going to shift underneath us. Also if we try to check
-	// against the runtime/metrics package in an automated fashion we're kind
-	// of missing the point, because we have to do all the same work the code
-	// has to do to perform the translation. Same for supporting old metric
-	// names (the best we can do here is make sure they're all accounted for).
-	var sysBytes, allocs float64
-	for _, m := range metrics {
-		name := m.Desc().fqName
-		switch name {
-		case "go_memory_classes_total_bytes":
-			checkMemoryMetric(t, m, &sysBytes)
-		case "go_sys_bytes":
-			checkMemoryMetric(t, m, &sysBytes)
-		case "go_gc_heap_allocs_bytes_total":
-			checkMemoryMetric(t, m, &allocs)
-		case "go_alloc_bytes_total":
-			checkMemoryMetric(t, m, &allocs)
-		}
-		if present, ok := msChecklist[name]; ok {
-			if present {
-				t.Errorf("memstats metric %s found more than once", name)
-			}
-			msChecklist[name] = true
-		}
-	}
-	for name := range msChecklist {
-		if present := msChecklist[name]; !present {
-			t.Errorf("memstats metric %s not collected", name)
-		}
+func TestRmForMemStats(t *testing.T) {
+	if got, want := len(bestEffortLookupRM(rmForMemStats)), len(rmForMemStats); got != want {
+		t.Errorf("got %d, want %d metrics", got, want)
 	}
 }

-func checkMemoryMetric(t *testing.T, m Metric, expValue *float64) {
-	t.Helper()
+func expectedBaseMetrics() map[string]struct{} {
+	metrics := map[string]struct{}{}
+	b := newBaseGoCollector()
+	for _, m := range []string{
+		b.gcDesc.fqName,
+		b.goInfoDesc.fqName,
+		b.goroutinesDesc.fqName,
+		b.gcLastTimeDesc.fqName,
+		b.threadsDesc.fqName,
+	} {
+		metrics[m] = struct{}{}
+	}
+	return metrics
+}

-	pb := &dto.Metric{}
-	m.Write(pb)
-	var value float64
-	if g := pb.GetGauge(); g != nil {
-		value = g.GetValue()
-	} else {
-		value = pb.GetCounter().GetValue()
+func addExpectedRuntimeMemStats(metrics map[string]struct{}) map[string]struct{} {
+	for _, m := range goRuntimeMemStats() {
+		metrics[m.desc.fqName] = struct{}{}
 	}
-	if value <= 0 {
-		t.Error("bad value for total memory")
+	return metrics
+}
+
+func addExpectedRuntimeMetrics(metrics map[string]struct{}) map[string]struct{} {
+	for _, m := range expectedRuntimeMetrics {
+		metrics[m] = struct{}{}
 	}
-	if *expValue == 0 {
-		*expValue = value
-	} else if value != *expValue {
-		t.Errorf("legacy metric and runtime/metrics metric do not match: want %d, got %d", int64(*expValue), int64(value))
+	return metrics
+}
+
+func TestGoCollector(t *testing.T) {
+	for _, tcase := range []struct {
+		collections       uint32
+		expectedFQNameSet map[string]struct{}
+	}{
+		{
+			collections:       0,
+			expectedFQNameSet: expectedBaseMetrics(),
+		},
+		{
+			collections:       goRuntimeMemStatsCollection,
+			expectedFQNameSet: addExpectedRuntimeMemStats(expectedBaseMetrics()),
+		},
+		{
+			collections:       goRuntimeMetricsCollection,
+			expectedFQNameSet: addExpectedRuntimeMetrics(expectedBaseMetrics()),
+		},
+		{
+			collections:       goRuntimeMemStatsCollection | goRuntimeMetricsCollection,
+			expectedFQNameSet: addExpectedRuntimeMemStats(addExpectedRuntimeMetrics(expectedBaseMetrics())),
+		},
+	} {
+		if ok := t.Run("", func(t *testing.T) {
+			goMetrics := collectGoMetrics(t, tcase.collections)
+			goMetricSet := make(map[string]Metric)
+			for _, m := range goMetrics {
+				goMetricSet[m.Desc().fqName] = m
+			}
+
+			for i := range goMetrics {
+				name := goMetrics[i].Desc().fqName
+
+				if _, ok := tcase.expectedFQNameSet[name]; !ok {
+					t.Errorf("found unpexpected metric %s", name)
+					continue
+				}
+			}
+
+			// Now iterate over the expected metrics and look for removals.
+			for expectedName := range tcase.expectedFQNameSet {
+				if _, ok := goMetricSet[expectedName]; !ok {
+					t.Errorf("missing expected metric %s in collection", expectedName)
+					continue
+				}
+			}
+		}); !ok {
+			return
+		}
 	}
 }

 var sink interface{}

 func TestBatchHistogram(t *testing.T) {
-	goMetrics := collectGoMetrics(t)
+	goMetrics := collectGoMetrics(t, goRuntimeMetricsCollection)

 	var mhist Metric
 	for _, m := range goMetrics {
-		if m.Desc().fqName == "go_gc_heap_allocs_by_size_bytes_total" {
+		if m.Desc().fqName == "go_gc_heap_allocs_by_size_bytes" {
 			mhist = m
 			break
 		}
@ -126,7 +145,7 @@ func TestBatchHistogram(t *testing.T) {
 	for i := 0; i < 100; i++ {
 		sink = make([]byte, 128)
 	}
-	collectGoMetrics(t)
+	collectGoMetrics(t, defaultGoCollections)
 	for i, v := range hist.counts {
 		if v != countsCopy[i] {
 			t.Error("counts changed during new collection")
@ -175,10 +194,12 @@ func TestBatchHistogram(t *testing.T) {
 	}
 }

-func collectGoMetrics(t *testing.T) []Metric {
+func collectGoMetrics(t *testing.T, enabledCollections uint32) []Metric {
 	t.Helper()

-	c := NewGoCollector().(*goCollector)
+	c := NewGoCollector(func(o *GoCollectorOptions) {
+		o.EnabledCollections = enabledCollections
+	}).(*goCollector)

 	// Collect all metrics.
 	ch := make(chan Metric)
@ -201,7 +222,8 @@ func collectGoMetrics(t *testing.T) []Metric {

 func TestMemStatsEquivalence(t *testing.T) {
 	var msReal, msFake runtime.MemStats
-	descs := metrics.All()
+	descs := bestEffortLookupRM(rmForMemStats)
+
 	samples := make([]metrics.Sample, len(descs))
 	samplesMap := make(map[string]*metrics.Sample)
 	for i := range descs {
@ -214,9 +236,9 @@ func TestMemStatsEquivalence(t *testing.T) {

 	// Populate msReal.
 	runtime.ReadMemStats(&msReal)
-
-	// Populate msFake.
+	// Populate msFake and hope that no GC happened in between (:
 	metrics.Read(samples)
+
 	memStatsFromRM(&msFake, samplesMap)

 	// Iterate over them and make sure they're somewhat close.
@ -227,9 +249,16 @@ func TestMemStatsEquivalence(t *testing.T) {
 	for i := 0; i < msRealValue.NumField(); i++ {
 		fr := msRealValue.Field(i)
 		ff := msFakeValue.Field(i)
-		switch typ.Kind() {
+
+		if typ.Field(i).Name == "PauseTotalNs" || typ.Field(i).Name == "LastGC" {
+			// We don't use those fields for metrics,
+			// thus we are not interested in having this filled.
+			continue
+		}
+		switch fr.Kind() {
+		// Fields which we are interested in are all uint64s.
+		// The only float64 field GCCPUFraction is by design omitted.
 		case reflect.Uint64:
-			// N.B. Almost all fields of MemStats are uint64s.
 			vr := fr.Interface().(uint64)
 			vf := ff.Interface().(uint64)
 			if float64(vr-vf)/float64(vf) > 0.05 {
@ -240,7 +269,7 @@ func TestMemStatsEquivalence(t *testing.T) {
 }

 func TestExpectedRuntimeMetrics(t *testing.T) {
-	goMetrics := collectGoMetrics(t)
+	goMetrics := collectGoMetrics(t, goRuntimeMetricsCollection)
 	goMetricSet := make(map[string]Metric)
 	for _, m := range goMetrics {
 		goMetricSet[m.Desc().fqName] = m
@ -253,6 +282,7 @@ func TestExpectedRuntimeMetrics(t *testing.T) {
 		rmName := descs[i].Name
 		rmSet[rmName] = struct{}{}

+		// expectedRuntimeMetrics depends on Go version.
 		expFQName, ok := expectedRuntimeMetrics[rmName]
 		if !ok {
 			t.Errorf("found new runtime/metrics metric %s", rmName)
@ -268,6 +298,7 @@ func TestExpectedRuntimeMetrics(t *testing.T) {
 			continue
 		}
 	}
+
 	// Now iterate over the expected metrics and look for removals.
 	cardinality := 0
 	for rmName, fqName := range expectedRuntimeMetrics {
--- a/prometheus/go_collector_metrics_go117_test.go
+++ b/prometheus/go_collector_metrics_go117_test.go
@ -10,16 +10,16 @@ var expectedRuntimeMetrics = map[string]string{
 	"/gc/cycles/automatic:gc-cycles":              "go_gc_cycles_automatic_gc_cycles_total",
 	"/gc/cycles/forced:gc-cycles":                 "go_gc_cycles_forced_gc_cycles_total",
 	"/gc/cycles/total:gc-cycles":                  "go_gc_cycles_total_gc_cycles_total",
-	"/gc/heap/allocs-by-size:bytes":               "go_gc_heap_allocs_by_size_bytes_total",
+	"/gc/heap/allocs-by-size:bytes":               "go_gc_heap_allocs_by_size_bytes",
 	"/gc/heap/allocs:bytes":                       "go_gc_heap_allocs_bytes_total",
 	"/gc/heap/allocs:objects":                     "go_gc_heap_allocs_objects_total",
-	"/gc/heap/frees-by-size:bytes":                "go_gc_heap_frees_by_size_bytes_total",
+	"/gc/heap/frees-by-size:bytes":                "go_gc_heap_frees_by_size_bytes",
 	"/gc/heap/frees:bytes":                        "go_gc_heap_frees_bytes_total",
 	"/gc/heap/frees:objects":                      "go_gc_heap_frees_objects_total",
 	"/gc/heap/goal:bytes":                         "go_gc_heap_goal_bytes",
 	"/gc/heap/objects:objects":                    "go_gc_heap_objects_objects",
 	"/gc/heap/tiny/allocs:objects":                "go_gc_heap_tiny_allocs_objects_total",
-	"/gc/pauses:seconds":                          "go_gc_pauses_seconds_total",
+	"/gc/pauses:seconds":                          "go_gc_pauses_seconds",
 	"/memory/classes/heap/free:bytes":             "go_memory_classes_heap_free_bytes",
 	"/memory/classes/heap/objects:bytes":          "go_memory_classes_heap_objects_bytes",
 	"/memory/classes/heap/released:bytes":         "go_memory_classes_heap_released_bytes",
@ -38,4 +38,4 @@ var expectedRuntimeMetrics = map[string]string{
 	"/sched/latencies:seconds":                    "go_sched_latencies_seconds",
 }

-const expectedRuntimeMetricsCardinality = 79
+const expectedRuntimeMetricsCardinality = 77
--- a/prometheus/go_collector_metrics_go118_test.go
+++ b/prometheus/go_collector_metrics_go118_test.go
@ -0,0 +1,41 @@
+// Code generated by gen_go_collector_metrics_set.go; DO NOT EDIT.
+//go:generate go run gen_go_collector_metrics_set.go go1.18
+
+//go:build go1.18 && !go1.19
+// +build go1.18,!go1.19
+
+package prometheus
+
+var expectedRuntimeMetrics = map[string]string{
+	"/gc/cycles/automatic:gc-cycles":              "go_gc_cycles_automatic_gc_cycles_total",
+	"/gc/cycles/forced:gc-cycles":                 "go_gc_cycles_forced_gc_cycles_total",
+	"/gc/cycles/total:gc-cycles":                  "go_gc_cycles_total_gc_cycles_total",
+	"/gc/heap/allocs-by-size:bytes":               "go_gc_heap_allocs_by_size_bytes",
+	"/gc/heap/allocs:bytes":                       "go_gc_heap_allocs_bytes_total",
+	"/gc/heap/allocs:objects":                     "go_gc_heap_allocs_objects_total",
+	"/gc/heap/frees-by-size:bytes":                "go_gc_heap_frees_by_size_bytes",
+	"/gc/heap/frees:bytes":                        "go_gc_heap_frees_bytes_total",
+	"/gc/heap/frees:objects":                      "go_gc_heap_frees_objects_total",
+	"/gc/heap/goal:bytes":                         "go_gc_heap_goal_bytes",
+	"/gc/heap/objects:objects":                    "go_gc_heap_objects_objects",
+	"/gc/heap/tiny/allocs:objects":                "go_gc_heap_tiny_allocs_objects_total",
+	"/gc/pauses:seconds":                          "go_gc_pauses_seconds",
+	"/memory/classes/heap/free:bytes":             "go_memory_classes_heap_free_bytes",
+	"/memory/classes/heap/objects:bytes":          "go_memory_classes_heap_objects_bytes",
+	"/memory/classes/heap/released:bytes":         "go_memory_classes_heap_released_bytes",
+	"/memory/classes/heap/stacks:bytes":           "go_memory_classes_heap_stacks_bytes",
+	"/memory/classes/heap/unused:bytes":           "go_memory_classes_heap_unused_bytes",
+	"/memory/classes/metadata/mcache/free:bytes":  "go_memory_classes_metadata_mcache_free_bytes",
+	"/memory/classes/metadata/mcache/inuse:bytes": "go_memory_classes_metadata_mcache_inuse_bytes",
+	"/memory/classes/metadata/mspan/free:bytes":   "go_memory_classes_metadata_mspan_free_bytes",
+	"/memory/classes/metadata/mspan/inuse:bytes":  "go_memory_classes_metadata_mspan_inuse_bytes",
+	"/memory/classes/metadata/other:bytes":        "go_memory_classes_metadata_other_bytes",
+	"/memory/classes/os-stacks:bytes":             "go_memory_classes_os_stacks_bytes",
+	"/memory/classes/other:bytes":                 "go_memory_classes_other_bytes",
+	"/memory/classes/profiling/buckets:bytes":     "go_memory_classes_profiling_buckets_bytes",
+	"/memory/classes/total:bytes":                 "go_memory_classes_total_bytes",
+	"/sched/goroutines:goroutines":                "go_sched_goroutines_goroutines",
+	"/sched/latencies:seconds":                    "go_sched_latencies_seconds",
+}
+
+const expectedRuntimeMetricsCardinality = 77
--- a/prometheus/graphite/bridge.go
+++ b/prometheus/graphite/bridge.go
@ -197,14 +197,16 @@ func writeMetrics(w io.Writer, mfs []*dto.MetricFamily, useTags bool, prefix str

 	buf := bufio.NewWriter(w)
 	for _, s := range vec {
-		for _, c := range prefix {
-			if _, err := buf.WriteRune(c); err != nil {
+		if prefix != "" {
+			for _, c := range prefix {
+				if _, err := buf.WriteRune(c); err != nil {
+					return err
+				}
+			}
+			if err := buf.WriteByte('.'); err != nil {
 				return err
 			}
 		}
-		if err := buf.WriteByte('.'); err != nil {
-			return err
-		}
 		if err := writeMetric(buf, s.Metric, useTags); err != nil {
 			return err
 		}
--- a/prometheus/graphite/bridge_test.go
+++ b/prometheus/graphite/bridge_test.go
@ -101,6 +101,7 @@ func testWriteSummary(t *testing.T, useTags bool) {
 		{prefix: "prefix"},
 		{prefix: "pre/fix"},
 		{prefix: "pre.fix"},
+		{prefix: ""},
 	}

 	var (
@ -141,10 +142,15 @@ func testWriteSummary(t *testing.T, useTags bool) {
 			t.Fatalf("error: %v", err)
 		}

-		wantWithPrefix := fmt.Sprintf(want,
-			tc.prefix, tc.prefix, tc.prefix, tc.prefix, tc.prefix,
-			tc.prefix, tc.prefix, tc.prefix, tc.prefix, tc.prefix,
-		)
+		var wantWithPrefix string
+		if tc.prefix == "" {
+			wantWithPrefix = strings.ReplaceAll(want, "%s.", "")
+		} else {
+			wantWithPrefix = fmt.Sprintf(want,
+				tc.prefix, tc.prefix, tc.prefix, tc.prefix, tc.prefix,
+				tc.prefix, tc.prefix, tc.prefix, tc.prefix, tc.prefix,
+			)
+		}

 		got := buf.String()

--- a/prometheus/histogram.go
+++ b/prometheus/histogram.go
@ -1125,11 +1125,11 @@ func (h *constHistogram) Desc() *Desc {

 func (h *constHistogram) Write(out *dto.Metric) error {
 	his := &dto.Histogram{}
+
 	buckets := make([]*dto.Bucket, 0, len(h.buckets))

 	his.SampleCount = proto.Uint64(h.count)
 	his.SampleSum = proto.Float64(h.sum)
-
 	for upperBound, count := range h.buckets {
 		buckets = append(buckets, &dto.Bucket{
 			CumulativeCount: proto.Uint64(count),
--- a/prometheus/internal/difflib.go
+++ b/prometheus/internal/difflib.go
@ -0,0 +1,649 @@
+// Copyright 2022 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// It provides tools to compare sequences of strings and generate textual diffs.
+//
+// Maintaining `GetUnifiedDiffString` here because original repository
+// (https://github.com/pmezard/go-difflib) is no loger maintained.
+package internal
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"strings"
+)
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+func calculateRatio(matches, length int) float64 {
+	if length > 0 {
+		return 2.0 * float64(matches) / float64(length)
+	}
+	return 1.0
+}
+
+type Match struct {
+	A    int
+	B    int
+	Size int
+}
+
+type OpCode struct {
+	Tag byte
+	I1  int
+	I2  int
+	J1  int
+	J2  int
+}
+
+// SequenceMatcher compares sequence of strings. The basic
+// algorithm predates, and is a little fancier than, an algorithm
+// published in the late 1980's by Ratcliff and Obershelp under the
+// hyperbolic name "gestalt pattern matching".  The basic idea is to find
+// the longest contiguous matching subsequence that contains no "junk"
+// elements (R-O doesn't address junk).  The same idea is then applied
+// recursively to the pieces of the sequences to the left and to the right
+// of the matching subsequence.  This does not yield minimal edit
+// sequences, but does tend to yield matches that "look right" to people.
+//
+// SequenceMatcher tries to compute a "human-friendly diff" between two
+// sequences.  Unlike e.g. UNIX(tm) diff, the fundamental notion is the
+// longest *contiguous* & junk-free matching subsequence.  That's what
+// catches peoples' eyes.  The Windows(tm) windiff has another interesting
+// notion, pairing up elements that appear uniquely in each sequence.
+// That, and the method here, appear to yield more intuitive difference
+// reports than does diff.  This method appears to be the least vulnerable
+// to synching up on blocks of "junk lines", though (like blank lines in
+// ordinary text files, or maybe "<P>" lines in HTML files).  That may be
+// because this is the only method of the 3 that has a *concept* of
+// "junk" <wink>.
+//
+// Timing:  Basic R-O is cubic time worst case and quadratic time expected
+// case.  SequenceMatcher is quadratic time for the worst case and has
+// expected-case behavior dependent in a complicated way on how many
+// elements the sequences have in common; best case time is linear.
+type SequenceMatcher struct {
+	a              []string
+	b              []string
+	b2j            map[string][]int
+	IsJunk         func(string) bool
+	autoJunk       bool
+	bJunk          map[string]struct{}
+	matchingBlocks []Match
+	fullBCount     map[string]int
+	bPopular       map[string]struct{}
+	opCodes        []OpCode
+}
+
+func NewMatcher(a, b []string) *SequenceMatcher {
+	m := SequenceMatcher{autoJunk: true}
+	m.SetSeqs(a, b)
+	return &m
+}
+
+func NewMatcherWithJunk(a, b []string, autoJunk bool,
+	isJunk func(string) bool) *SequenceMatcher {
+
+	m := SequenceMatcher{IsJunk: isJunk, autoJunk: autoJunk}
+	m.SetSeqs(a, b)
+	return &m
+}
+
+// Set two sequences to be compared.
+func (m *SequenceMatcher) SetSeqs(a, b []string) {
+	m.SetSeq1(a)
+	m.SetSeq2(b)
+}
+
+// Set the first sequence to be compared. The second sequence to be compared is
+// not changed.
+//
+// SequenceMatcher computes and caches detailed information about the second
+// sequence, so if you want to compare one sequence S against many sequences,
+// use .SetSeq2(s) once and call .SetSeq1(x) repeatedly for each of the other
+// sequences.
+//
+// See also SetSeqs() and SetSeq2().
+func (m *SequenceMatcher) SetSeq1(a []string) {
+	if &a == &m.a {
+		return
+	}
+	m.a = a
+	m.matchingBlocks = nil
+	m.opCodes = nil
+}
+
+// Set the second sequence to be compared. The first sequence to be compared is
+// not changed.
+func (m *SequenceMatcher) SetSeq2(b []string) {
+	if &b == &m.b {
+		return
+	}
+	m.b = b
+	m.matchingBlocks = nil
+	m.opCodes = nil
+	m.fullBCount = nil
+	m.chainB()
+}
+
+func (m *SequenceMatcher) chainB() {
+	// Populate line -> index mapping
+	b2j := map[string][]int{}
+	for i, s := range m.b {
+		indices := b2j[s]
+		indices = append(indices, i)
+		b2j[s] = indices
+	}
+
+	// Purge junk elements
+	m.bJunk = map[string]struct{}{}
+	if m.IsJunk != nil {
+		junk := m.bJunk
+		for s, _ := range b2j {
+			if m.IsJunk(s) {
+				junk[s] = struct{}{}
+			}
+		}
+		for s, _ := range junk {
+			delete(b2j, s)
+		}
+	}
+
+	// Purge remaining popular elements
+	popular := map[string]struct{}{}
+	n := len(m.b)
+	if m.autoJunk && n >= 200 {
+		ntest := n/100 + 1
+		for s, indices := range b2j {
+			if len(indices) > ntest {
+				popular[s] = struct{}{}
+			}
+		}
+		for s, _ := range popular {
+			delete(b2j, s)
+		}
+	}
+	m.bPopular = popular
+	m.b2j = b2j
+}
+
+func (m *SequenceMatcher) isBJunk(s string) bool {
+	_, ok := m.bJunk[s]
+	return ok
+}
+
+// Find longest matching block in a[alo:ahi] and b[blo:bhi].
+//
+// If IsJunk is not defined:
+//
+// Return (i,j,k) such that a[i:i+k] is equal to b[j:j+k], where
+//     alo <= i <= i+k <= ahi
+//     blo <= j <= j+k <= bhi
+// and for all (i',j',k') meeting those conditions,
+//     k >= k'
+//     i <= i'
+//     and if i == i', j <= j'
+//
+// In other words, of all maximal matching blocks, return one that
+// starts earliest in a, and of all those maximal matching blocks that
+// start earliest in a, return the one that starts earliest in b.
+//
+// If IsJunk is defined, first the longest matching block is
+// determined as above, but with the additional restriction that no
+// junk element appears in the block.  Then that block is extended as
+// far as possible by matching (only) junk elements on both sides.  So
+// the resulting block never matches on junk except as identical junk
+// happens to be adjacent to an "interesting" match.
+//
+// If no blocks match, return (alo, blo, 0).
+func (m *SequenceMatcher) findLongestMatch(alo, ahi, blo, bhi int) Match {
+	// CAUTION:  stripping common prefix or suffix would be incorrect.
+	// E.g.,
+	//    ab
+	//    acab
+	// Longest matching block is "ab", but if common prefix is
+	// stripped, it's "a" (tied with "b").  UNIX(tm) diff does so
+	// strip, so ends up claiming that ab is changed to acab by
+	// inserting "ca" in the middle.  That's minimal but unintuitive:
+	// "it's obvious" that someone inserted "ac" at the front.
+	// Windiff ends up at the same place as diff, but by pairing up
+	// the unique 'b's and then matching the first two 'a's.
+	besti, bestj, bestsize := alo, blo, 0
+
+	// find longest junk-free match
+	// during an iteration of the loop, j2len[j] = length of longest
+	// junk-free match ending with a[i-1] and b[j]
+	j2len := map[int]int{}
+	for i := alo; i != ahi; i++ {
+		// look at all instances of a[i] in b; note that because
+		// b2j has no junk keys, the loop is skipped if a[i] is junk
+		newj2len := map[int]int{}
+		for _, j := range m.b2j[m.a[i]] {
+			// a[i] matches b[j]
+			if j < blo {
+				continue
+			}
+			if j >= bhi {
+				break
+			}
+			k := j2len[j-1] + 1
+			newj2len[j] = k
+			if k > bestsize {
+				besti, bestj, bestsize = i-k+1, j-k+1, k
+			}
+		}
+		j2len = newj2len
+	}
+
+	// Extend the best by non-junk elements on each end.  In particular,
+	// "popular" non-junk elements aren't in b2j, which greatly speeds
+	// the inner loop above, but also means "the best" match so far
+	// doesn't contain any junk *or* popular non-junk elements.
+	for besti > alo && bestj > blo && !m.isBJunk(m.b[bestj-1]) &&
+		m.a[besti-1] == m.b[bestj-1] {
+		besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
+	}
+	for besti+bestsize < ahi && bestj+bestsize < bhi &&
+		!m.isBJunk(m.b[bestj+bestsize]) &&
+		m.a[besti+bestsize] == m.b[bestj+bestsize] {
+		bestsize += 1
+	}
+
+	// Now that we have a wholly interesting match (albeit possibly
+	// empty!), we may as well suck up the matching junk on each
+	// side of it too.  Can't think of a good reason not to, and it
+	// saves post-processing the (possibly considerable) expense of
+	// figuring out what to do with it.  In the case of an empty
+	// interesting match, this is clearly the right thing to do,
+	// because no other kind of match is possible in the regions.
+	for besti > alo && bestj > blo && m.isBJunk(m.b[bestj-1]) &&
+		m.a[besti-1] == m.b[bestj-1] {
+		besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
+	}
+	for besti+bestsize < ahi && bestj+bestsize < bhi &&
+		m.isBJunk(m.b[bestj+bestsize]) &&
+		m.a[besti+bestsize] == m.b[bestj+bestsize] {
+		bestsize += 1
+	}
+
+	return Match{A: besti, B: bestj, Size: bestsize}
+}
+
+// Return list of triples describing matching subsequences.
+//
+// Each triple is of the form (i, j, n), and means that
+// a[i:i+n] == b[j:j+n].  The triples are monotonically increasing in
+// i and in j. It's also guaranteed that if (i, j, n) and (i', j', n') are
+// adjacent triples in the list, and the second is not the last triple in the
+// list, then i+n != i' or j+n != j'. IOW, adjacent triples never describe
+// adjacent equal blocks.
+//
+// The last triple is a dummy, (len(a), len(b), 0), and is the only
+// triple with n==0.
+func (m *SequenceMatcher) GetMatchingBlocks() []Match {
+	if m.matchingBlocks != nil {
+		return m.matchingBlocks
+	}
+
+	var matchBlocks func(alo, ahi, blo, bhi int, matched []Match) []Match
+	matchBlocks = func(alo, ahi, blo, bhi int, matched []Match) []Match {
+		match := m.findLongestMatch(alo, ahi, blo, bhi)
+		i, j, k := match.A, match.B, match.Size
+		if match.Size > 0 {
+			if alo < i && blo < j {
+				matched = matchBlocks(alo, i, blo, j, matched)
+			}
+			matched = append(matched, match)
+			if i+k < ahi && j+k < bhi {
+				matched = matchBlocks(i+k, ahi, j+k, bhi, matched)
+			}
+		}
+		return matched
+	}
+	matched := matchBlocks(0, len(m.a), 0, len(m.b), nil)
+
+	// It's possible that we have adjacent equal blocks in the
+	// matching_blocks list now.
+	nonAdjacent := []Match{}
+	i1, j1, k1 := 0, 0, 0
+	for _, b := range matched {
+		// Is this block adjacent to i1, j1, k1?
+		i2, j2, k2 := b.A, b.B, b.Size
+		if i1+k1 == i2 && j1+k1 == j2 {
+			// Yes, so collapse them -- this just increases the length of
+			// the first block by the length of the second, and the first
+			// block so lengthened remains the block to compare against.
+			k1 += k2
+		} else {
+			// Not adjacent.  Remember the first block (k1==0 means it's
+			// the dummy we started with), and make the second block the
+			// new block to compare against.
+			if k1 > 0 {
+				nonAdjacent = append(nonAdjacent, Match{i1, j1, k1})
+			}
+			i1, j1, k1 = i2, j2, k2
+		}
+	}
+	if k1 > 0 {
+		nonAdjacent = append(nonAdjacent, Match{i1, j1, k1})
+	}
+
+	nonAdjacent = append(nonAdjacent, Match{len(m.a), len(m.b), 0})
+	m.matchingBlocks = nonAdjacent
+	return m.matchingBlocks
+}
+
+// Return list of 5-tuples describing how to turn a into b.
+//
+// Each tuple is of the form (tag, i1, i2, j1, j2).  The first tuple
+// has i1 == j1 == 0, and remaining tuples have i1 == the i2 from the
+// tuple preceding it, and likewise for j1 == the previous j2.
+//
+// The tags are characters, with these meanings:
+//
+// 'r' (replace):  a[i1:i2] should be replaced by b[j1:j2]
+//
+// 'd' (delete):   a[i1:i2] should be deleted, j1==j2 in this case.
+//
+// 'i' (insert):   b[j1:j2] should be inserted at a[i1:i1], i1==i2 in this case.
+//
+// 'e' (equal):    a[i1:i2] == b[j1:j2]
+func (m *SequenceMatcher) GetOpCodes() []OpCode {
+	if m.opCodes != nil {
+		return m.opCodes
+	}
+	i, j := 0, 0
+	matching := m.GetMatchingBlocks()
+	opCodes := make([]OpCode, 0, len(matching))
+	for _, m := range matching {
+		//  invariant:  we've pumped out correct diffs to change
+		//  a[:i] into b[:j], and the next matching block is
+		//  a[ai:ai+size] == b[bj:bj+size]. So we need to pump
+		//  out a diff to change a[i:ai] into b[j:bj], pump out
+		//  the matching block, and move (i,j) beyond the match
+		ai, bj, size := m.A, m.B, m.Size
+		tag := byte(0)
+		if i < ai && j < bj {
+			tag = 'r'
+		} else if i < ai {
+			tag = 'd'
+		} else if j < bj {
+			tag = 'i'
+		}
+		if tag > 0 {
+			opCodes = append(opCodes, OpCode{tag, i, ai, j, bj})
+		}
+		i, j = ai+size, bj+size
+		// the list of matching blocks is terminated by a
+		// sentinel with size 0
+		if size > 0 {
+			opCodes = append(opCodes, OpCode{'e', ai, i, bj, j})
+		}
+	}
+	m.opCodes = opCodes
+	return m.opCodes
+}
+
+// Isolate change clusters by eliminating ranges with no changes.
+//
+// Return a generator of groups with up to n lines of context.
+// Each group is in the same format as returned by GetOpCodes().
+func (m *SequenceMatcher) GetGroupedOpCodes(n int) [][]OpCode {
+	if n < 0 {
+		n = 3
+	}
+	codes := m.GetOpCodes()
+	if len(codes) == 0 {
+		codes = []OpCode{{'e', 0, 1, 0, 1}}
+	}
+	// Fixup leading and trailing groups if they show no changes.
+	if codes[0].Tag == 'e' {
+		c := codes[0]
+		i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
+		codes[0] = OpCode{c.Tag, max(i1, i2-n), i2, max(j1, j2-n), j2}
+	}
+	if codes[len(codes)-1].Tag == 'e' {
+		c := codes[len(codes)-1]
+		i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
+		codes[len(codes)-1] = OpCode{c.Tag, i1, min(i2, i1+n), j1, min(j2, j1+n)}
+	}
+	nn := n + n
+	groups := [][]OpCode{}
+	group := []OpCode{}
+	for _, c := range codes {
+		i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
+		// End the current group and start a new one whenever
+		// there is a large range with no changes.
+		if c.Tag == 'e' && i2-i1 > nn {
+			group = append(group, OpCode{c.Tag, i1, min(i2, i1+n),
+				j1, min(j2, j1+n)})
+			groups = append(groups, group)
+			group = []OpCode{}
+			i1, j1 = max(i1, i2-n), max(j1, j2-n)
+		}
+		group = append(group, OpCode{c.Tag, i1, i2, j1, j2})
+	}
+	if len(group) > 0 && !(len(group) == 1 && group[0].Tag == 'e') {
+		groups = append(groups, group)
+	}
+	return groups
+}
+
+// Return a measure of the sequences' similarity (float in [0,1]).
+//
+// Where T is the total number of elements in both sequences, and
+// M is the number of matches, this is 2.0*M / T.
+// Note that this is 1 if the sequences are identical, and 0 if
+// they have nothing in common.
+//
+// .Ratio() is expensive to compute if you haven't already computed
+// .GetMatchingBlocks() or .GetOpCodes(), in which case you may
+// want to try .QuickRatio() or .RealQuickRation() first to get an
+// upper bound.
+func (m *SequenceMatcher) Ratio() float64 {
+	matches := 0
+	for _, m := range m.GetMatchingBlocks() {
+		matches += m.Size
+	}
+	return calculateRatio(matches, len(m.a)+len(m.b))
+}
+
+// Return an upper bound on ratio() relatively quickly.
+//
+// This isn't defined beyond that it is an upper bound on .Ratio(), and
+// is faster to compute.
+func (m *SequenceMatcher) QuickRatio() float64 {
+	// viewing a and b as multisets, set matches to the cardinality
+	// of their intersection; this counts the number of matches
+	// without regard to order, so is clearly an upper bound
+	if m.fullBCount == nil {
+		m.fullBCount = map[string]int{}
+		for _, s := range m.b {
+			m.fullBCount[s] = m.fullBCount[s] + 1
+		}
+	}
+
+	// avail[x] is the number of times x appears in 'b' less the
+	// number of times we've seen it in 'a' so far ... kinda
+	avail := map[string]int{}
+	matches := 0
+	for _, s := range m.a {
+		n, ok := avail[s]
+		if !ok {
+			n = m.fullBCount[s]
+		}
+		avail[s] = n - 1
+		if n > 0 {
+			matches += 1
+		}
+	}
+	return calculateRatio(matches, len(m.a)+len(m.b))
+}
+
+// Return an upper bound on ratio() very quickly.
+//
+// This isn't defined beyond that it is an upper bound on .Ratio(), and
+// is faster to compute than either .Ratio() or .QuickRatio().
+func (m *SequenceMatcher) RealQuickRatio() float64 {
+	la, lb := len(m.a), len(m.b)
+	return calculateRatio(min(la, lb), la+lb)
+}
+
+// Convert range to the "ed" format
+func formatRangeUnified(start, stop int) string {
+	// Per the diff spec at http://www.unix.org/single_unix_specification/
+	beginning := start + 1 // lines start numbering with one
+	length := stop - start
+	if length == 1 {
+		return fmt.Sprintf("%d", beginning)
+	}
+	if length == 0 {
+		beginning -= 1 // empty ranges begin at line just before the range
+	}
+	return fmt.Sprintf("%d,%d", beginning, length)
+}
+
+// Unified diff parameters
+type UnifiedDiff struct {
+	A        []string // First sequence lines
+	FromFile string   // First file name
+	FromDate string   // First file time
+	B        []string // Second sequence lines
+	ToFile   string   // Second file name
+	ToDate   string   // Second file time
+	Eol      string   // Headers end of line, defaults to LF
+	Context  int      // Number of context lines
+}
+
+// Compare two sequences of lines; generate the delta as a unified diff.
+//
+// Unified diffs are a compact way of showing line changes and a few
+// lines of context.  The number of context lines is set by 'n' which
+// defaults to three.
+//
+// By default, the diff control lines (those with ---, +++, or @@) are
+// created with a trailing newline.  This is helpful so that inputs
+// created from file.readlines() result in diffs that are suitable for
+// file.writelines() since both the inputs and outputs have trailing
+// newlines.
+//
+// For inputs that do not have trailing newlines, set the lineterm
+// argument to "" so that the output will be uniformly newline free.
+//
+// The unidiff format normally has a header for filenames and modification
+// times.  Any or all of these may be specified using strings for
+// 'fromfile', 'tofile', 'fromfiledate', and 'tofiledate'.
+// The modification times are normally expressed in the ISO 8601 format.
+func WriteUnifiedDiff(writer io.Writer, diff UnifiedDiff) error {
+	buf := bufio.NewWriter(writer)
+	defer buf.Flush()
+	wf := func(format string, args ...interface{}) error {
+		_, err := buf.WriteString(fmt.Sprintf(format, args...))
+		return err
+	}
+	ws := func(s string) error {
+		_, err := buf.WriteString(s)
+		return err
+	}
+
+	if len(diff.Eol) == 0 {
+		diff.Eol = "\n"
+	}
+
+	started := false
+	m := NewMatcher(diff.A, diff.B)
+	for _, g := range m.GetGroupedOpCodes(diff.Context) {
+		if !started {
+			started = true
+			fromDate := ""
+			if len(diff.FromDate) > 0 {
+				fromDate = "\t" + diff.FromDate
+			}
+			toDate := ""
+			if len(diff.ToDate) > 0 {
+				toDate = "\t" + diff.ToDate
+			}
+			if diff.FromFile != "" || diff.ToFile != "" {
+				err := wf("--- %s%s%s", diff.FromFile, fromDate, diff.Eol)
+				if err != nil {
+					return err
+				}
+				err = wf("+++ %s%s%s", diff.ToFile, toDate, diff.Eol)
+				if err != nil {
+					return err
+				}
+			}
+		}
+		first, last := g[0], g[len(g)-1]
+		range1 := formatRangeUnified(first.I1, last.I2)
+		range2 := formatRangeUnified(first.J1, last.J2)
+		if err := wf("@@ -%s +%s @@%s", range1, range2, diff.Eol); err != nil {
+			return err
+		}
+		for _, c := range g {
+			i1, i2, j1, j2 := c.I1, c.I2, c.J1, c.J2
+			if c.Tag == 'e' {
+				for _, line := range diff.A[i1:i2] {
+					if err := ws(" " + line); err != nil {
+						return err
+					}
+				}
+				continue
+			}
+			if c.Tag == 'r' || c.Tag == 'd' {
+				for _, line := range diff.A[i1:i2] {
+					if err := ws("-" + line); err != nil {
+						return err
+					}
+				}
+			}
+			if c.Tag == 'r' || c.Tag == 'i' {
+				for _, line := range diff.B[j1:j2] {
+					if err := ws("+" + line); err != nil {
+						return err
+					}
+				}
+			}
+		}
+	}
+	return nil
+}
+
+// Like WriteUnifiedDiff but returns the diff a string.
+func GetUnifiedDiffString(diff UnifiedDiff) (string, error) {
+	w := &bytes.Buffer{}
+	err := WriteUnifiedDiff(w, diff)
+	return string(w.Bytes()), err
+}
+
+// Split a string on "\n" while preserving them. The output can be used
+// as input for UnifiedDiff and ContextDiff structures.
+func SplitLines(s string) []string {
+	lines := strings.SplitAfter(s, "\n")
+	lines[len(lines)-1] += "\n"
+	return lines
+}
--- a/prometheus/internal/difflib_test.go
+++ b/prometheus/internal/difflib_test.go
@ -0,0 +1,266 @@
+// Copyright 2022 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package internal
+
+import (
+	"bytes"
+	"fmt"
+	"math"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+func assertAlmostEqual(t *testing.T, a, b float64, places int) {
+	if math.Abs(a-b) > math.Pow10(-places) {
+		t.Errorf("%.7f != %.7f", a, b)
+	}
+}
+
+func assertEqual(t *testing.T, a, b interface{}) {
+	if !reflect.DeepEqual(a, b) {
+		t.Errorf("%v != %v", a, b)
+	}
+}
+
+func splitChars(s string) []string {
+	chars := make([]string, 0, len(s))
+	// Assume ASCII inputs
+	for i := 0; i != len(s); i++ {
+		chars = append(chars, string(s[i]))
+	}
+	return chars
+}
+
+func TestSequenceMatcherRatio(t *testing.T) {
+	s := NewMatcher(splitChars("abcd"), splitChars("bcde"))
+	assertEqual(t, s.Ratio(), 0.75)
+	assertEqual(t, s.QuickRatio(), 0.75)
+	assertEqual(t, s.RealQuickRatio(), 1.0)
+}
+
+func TestGetOptCodes(t *testing.T) {
+	a := "qabxcd"
+	b := "abycdf"
+	s := NewMatcher(splitChars(a), splitChars(b))
+	w := &bytes.Buffer{}
+	for _, op := range s.GetOpCodes() {
+		fmt.Fprintf(w, "%s a[%d:%d], (%s) b[%d:%d] (%s)\n", string(op.Tag),
+			op.I1, op.I2, a[op.I1:op.I2], op.J1, op.J2, b[op.J1:op.J2])
+	}
+	result := string(w.Bytes())
+	expected := `d a[0:1], (q) b[0:0] ()
+e a[1:3], (ab) b[0:2] (ab)
+r a[3:4], (x) b[2:3] (y)
+e a[4:6], (cd) b[3:5] (cd)
+i a[6:6], () b[5:6] (f)
+`
+	if expected != result {
+		t.Errorf("unexpected op codes: \n%s", result)
+	}
+}
+
+func TestGroupedOpCodes(t *testing.T) {
+	a := []string{}
+	for i := 0; i != 39; i++ {
+		a = append(a, fmt.Sprintf("%02d", i))
+	}
+	b := []string{}
+	b = append(b, a[:8]...)
+	b = append(b, " i")
+	b = append(b, a[8:19]...)
+	b = append(b, " x")
+	b = append(b, a[20:22]...)
+	b = append(b, a[27:34]...)
+	b = append(b, " y")
+	b = append(b, a[35:]...)
+	s := NewMatcher(a, b)
+	w := &bytes.Buffer{}
+	for _, g := range s.GetGroupedOpCodes(-1) {
+		fmt.Fprintf(w, "group\n")
+		for _, op := range g {
+			fmt.Fprintf(w, "  %s, %d, %d, %d, %d\n", string(op.Tag),
+				op.I1, op.I2, op.J1, op.J2)
+		}
+	}
+	result := string(w.Bytes())
+	expected := `group
+  e, 5, 8, 5, 8
+  i, 8, 8, 8, 9
+  e, 8, 11, 9, 12
+group
+  e, 16, 19, 17, 20
+  r, 19, 20, 20, 21
+  e, 20, 22, 21, 23
+  d, 22, 27, 23, 23
+  e, 27, 30, 23, 26
+group
+  e, 31, 34, 27, 30
+  r, 34, 35, 30, 31
+  e, 35, 38, 31, 34
+`
+	if expected != result {
+		t.Errorf("unexpected op codes: \n%s", result)
+	}
+}
+
+func ExampleGetUnifiedDiffCode() {
+	a := `one
+two
+three
+four
+fmt.Printf("%s,%T",a,b)`
+	b := `zero
+one
+three
+four`
+	diff := UnifiedDiff{
+		A:        SplitLines(a),
+		B:        SplitLines(b),
+		FromFile: "Original",
+		FromDate: "2005-01-26 23:30:50",
+		ToFile:   "Current",
+		ToDate:   "2010-04-02 10:20:52",
+		Context:  3,
+	}
+	result, _ := GetUnifiedDiffString(diff)
+	fmt.Println(strings.Replace(result, "\t", " ", -1))
+	// Output:
+	// --- Original 2005-01-26 23:30:50
+	// +++ Current 2010-04-02 10:20:52
+	// @@ -1,5 +1,4 @@
+	// +zero
+	//  one
+	// -two
+	//  three
+	//  four
+	// -fmt.Printf("%s,%T",a,b)
+}
+
+func rep(s string, count int) string {
+	return strings.Repeat(s, count)
+}
+
+func TestWithAsciiOneInsert(t *testing.T) {
+	sm := NewMatcher(splitChars(rep("b", 100)),
+		splitChars("a"+rep("b", 100)))
+	assertAlmostEqual(t, sm.Ratio(), 0.995, 3)
+	assertEqual(t, sm.GetOpCodes(),
+		[]OpCode{{'i', 0, 0, 0, 1}, {'e', 0, 100, 1, 101}})
+	assertEqual(t, len(sm.bPopular), 0)
+
+	sm = NewMatcher(splitChars(rep("b", 100)),
+		splitChars(rep("b", 50)+"a"+rep("b", 50)))
+	assertAlmostEqual(t, sm.Ratio(), 0.995, 3)
+	assertEqual(t, sm.GetOpCodes(),
+		[]OpCode{{'e', 0, 50, 0, 50}, {'i', 50, 50, 50, 51}, {'e', 50, 100, 51, 101}})
+	assertEqual(t, len(sm.bPopular), 0)
+}
+
+func TestWithAsciiOnDelete(t *testing.T) {
+	sm := NewMatcher(splitChars(rep("a", 40)+"c"+rep("b", 40)),
+		splitChars(rep("a", 40)+rep("b", 40)))
+	assertAlmostEqual(t, sm.Ratio(), 0.994, 3)
+	assertEqual(t, sm.GetOpCodes(),
+		[]OpCode{{'e', 0, 40, 0, 40}, {'d', 40, 41, 40, 40}, {'e', 41, 81, 40, 80}})
+}
+
+func TestWithAsciiBJunk(t *testing.T) {
+	isJunk := func(s string) bool {
+		return s == " "
+	}
+	sm := NewMatcherWithJunk(splitChars(rep("a", 40)+rep("b", 40)),
+		splitChars(rep("a", 44)+rep("b", 40)), true, isJunk)
+	assertEqual(t, sm.bJunk, map[string]struct{}{})
+
+	sm = NewMatcherWithJunk(splitChars(rep("a", 40)+rep("b", 40)),
+		splitChars(rep("a", 44)+rep("b", 40)+rep(" ", 20)), false, isJunk)
+	assertEqual(t, sm.bJunk, map[string]struct{}{" ": struct{}{}})
+
+	isJunk = func(s string) bool {
+		return s == " " || s == "b"
+	}
+	sm = NewMatcherWithJunk(splitChars(rep("a", 40)+rep("b", 40)),
+		splitChars(rep("a", 44)+rep("b", 40)+rep(" ", 20)), false, isJunk)
+	assertEqual(t, sm.bJunk, map[string]struct{}{" ": struct{}{}, "b": struct{}{}})
+}
+
+func TestSFBugsRatioForNullSeqn(t *testing.T) {
+	sm := NewMatcher(nil, nil)
+	assertEqual(t, sm.Ratio(), 1.0)
+	assertEqual(t, sm.QuickRatio(), 1.0)
+	assertEqual(t, sm.RealQuickRatio(), 1.0)
+}
+
+func TestSFBugsComparingEmptyLists(t *testing.T) {
+	groups := NewMatcher(nil, nil).GetGroupedOpCodes(-1)
+	assertEqual(t, len(groups), 0)
+	diff := UnifiedDiff{
+		FromFile: "Original",
+		ToFile:   "Current",
+		Context:  3,
+	}
+	result, err := GetUnifiedDiffString(diff)
+	assertEqual(t, err, nil)
+	assertEqual(t, result, "")
+}
+
+func TestOutputFormatRangeFormatUnified(t *testing.T) {
+	// Per the diff spec at http://www.unix.org/single_unix_specification/
+	//
+	// Each <range> field shall be of the form:
+	//   %1d", <beginning line number>  if the range contains exactly one line,
+	// and:
+	//  "%1d,%1d", <beginning line number>, <number of lines> otherwise.
+	// If a range is empty, its beginning line number shall be the number of
+	// the line just before the range, or 0 if the empty range starts the file.
+	fm := formatRangeUnified
+	assertEqual(t, fm(3, 3), "3,0")
+	assertEqual(t, fm(3, 4), "4")
+	assertEqual(t, fm(3, 5), "4,2")
+	assertEqual(t, fm(3, 6), "4,3")
+	assertEqual(t, fm(0, 0), "0,0")
+}
+
+func TestSplitLines(t *testing.T) {
+	allTests := []struct {
+		input string
+		want  []string
+	}{
+		{"foo", []string{"foo\n"}},
+		{"foo\nbar", []string{"foo\n", "bar\n"}},
+		{"foo\nbar\n", []string{"foo\n", "bar\n", "\n"}},
+	}
+	for _, test := range allTests {
+		assertEqual(t, SplitLines(test.input), test.want)
+	}
+}
+
+func benchmarkSplitLines(b *testing.B, count int) {
+	str := strings.Repeat("foo\n", count)
+
+	b.ResetTimer()
+
+	n := 0
+	for i := 0; i < b.N; i++ {
+		n += len(SplitLines(str))
+	}
+}
+
+func BenchmarkSplitLines100(b *testing.B) {
+	benchmarkSplitLines(b, 100)
+}
+
+func BenchmarkSplitLines10000(b *testing.B) {
+	benchmarkSplitLines(b, 10000)
+}
--- a/prometheus/internal/go_runtime_metrics.go
+++ b/prometheus/internal/go_runtime_metrics.go
@ -62,7 +62,7 @@ func RuntimeMetricsToProm(d *metrics.Description) (string, string, string, bool)
 	// other data.
 	name = strings.ReplaceAll(name, "-", "_")
 	name = name + "_" + unit
-	if d.Cumulative {
+	if d.Cumulative && d.Kind != metrics.KindFloat64Histogram {
 		name = name + "_total"
 	}

@ -84,12 +84,12 @@ func RuntimeMetricsToProm(d *metrics.Description) (string, string, string, bool)
 func RuntimeMetricsBucketsForUnit(buckets []float64, unit string) []float64 {
 	switch unit {
 	case "bytes":
-		// Rebucket as powers of 2.
-		return rebucketExp(buckets, 2)
+		// Re-bucket as powers of 2.
+		return reBucketExp(buckets, 2)
 	case "seconds":
-		// Rebucket as powers of 10 and then merge all buckets greater
+		// Re-bucket as powers of 10 and then merge all buckets greater
 		// than 1 second into the +Inf bucket.
-		b := rebucketExp(buckets, 10)
+		b := reBucketExp(buckets, 10)
 		for i := range b {
 			if b[i] <= 1 {
 				continue
@ -103,11 +103,11 @@ func RuntimeMetricsBucketsForUnit(buckets []float64, unit string) []float64 {
 	return buckets
 }

-// rebucketExp takes a list of bucket boundaries (lower bound inclusive) and
+// reBucketExp takes a list of bucket boundaries (lower bound inclusive) and
 // downsamples the buckets to those a multiple of base apart. The end result
 // is a roughly exponential (in many cases, perfectly exponential) bucketing
 // scheme.
-func rebucketExp(buckets []float64, base float64) []float64 {
+func reBucketExp(buckets []float64, base float64) []float64 {
 	bucket := buckets[0]
 	var newBuckets []float64
 	// We may see a -Inf here, in which case, add it and skip it
--- a/prometheus/internal/metric.go
+++ b/prometheus/internal/metric.go
@ -19,18 +19,34 @@ import (
 	dto "github.com/prometheus/client_model/go"
 )

-// metricSorter is a sortable slice of *dto.Metric.
-type metricSorter []*dto.Metric
+// LabelPairSorter implements sort.Interface. It is used to sort a slice of
+// dto.LabelPair pointers.
+type LabelPairSorter []*dto.LabelPair

-func (s metricSorter) Len() int {
+func (s LabelPairSorter) Len() int {
 	return len(s)
 }

-func (s metricSorter) Swap(i, j int) {
+func (s LabelPairSorter) Swap(i, j int) {
 	s[i], s[j] = s[j], s[i]
 }

-func (s metricSorter) Less(i, j int) bool {
+func (s LabelPairSorter) Less(i, j int) bool {
+	return s[i].GetName() < s[j].GetName()
+}
+
+// MetricSorter is a sortable slice of *dto.Metric.
+type MetricSorter []*dto.Metric
+
+func (s MetricSorter) Len() int {
+	return len(s)
+}
+
+func (s MetricSorter) Swap(i, j int) {
+	s[i], s[j] = s[j], s[i]
+}
+
+func (s MetricSorter) Less(i, j int) bool {
 	if len(s[i].Label) != len(s[j].Label) {
 		// This should not happen. The metrics are
 		// inconsistent. However, we have to deal with the fact, as
@ -68,7 +84,7 @@ func (s metricSorter) Less(i, j int) bool {
 // the slice, with the contained Metrics sorted within each MetricFamily.
 func NormalizeMetricFamilies(metricFamiliesByName map[string]*dto.MetricFamily) []*dto.MetricFamily {
 	for _, mf := range metricFamiliesByName {
-		sort.Sort(metricSorter(mf.Metric))
+		sort.Sort(MetricSorter(mf.Metric))
 	}
 	names := make([]string, 0, len(metricFamiliesByName))
 	for name, mf := range metricFamiliesByName {
--- a/prometheus/metric.go
+++ b/prometheus/metric.go
@ -14,6 +14,8 @@
 package prometheus

 import (
+	"errors"
+	"sort"
 	"strings"
 	"time"

@ -115,22 +117,6 @@ func BuildFQName(namespace, subsystem, name string) string {
 	return name
 }

-// labelPairSorter implements sort.Interface. It is used to sort a slice of
-// dto.LabelPair pointers.
-type labelPairSorter []*dto.LabelPair
-
-func (s labelPairSorter) Len() int {
-	return len(s)
-}
-
-func (s labelPairSorter) Swap(i, j int) {
-	s[i], s[j] = s[j], s[i]
-}
-
-func (s labelPairSorter) Less(i, j int) bool {
-	return s[i].GetName() < s[j].GetName()
-}
-
 type invalidMetric struct {
 	desc *Desc
 	err  error
@ -174,3 +160,91 @@ func (m timestampedMetric) Write(pb *dto.Metric) error {
 func NewMetricWithTimestamp(t time.Time, m Metric) Metric {
 	return timestampedMetric{Metric: m, t: t}
 }
+
+type withExemplarsMetric struct {
+	Metric
+
+	exemplars []*dto.Exemplar
+}
+
+func (m *withExemplarsMetric) Write(pb *dto.Metric) error {
+	if err := m.Metric.Write(pb); err != nil {
+		return err
+	}
+
+	switch {
+	case pb.Counter != nil:
+		pb.Counter.Exemplar = m.exemplars[len(m.exemplars)-1]
+	case pb.Histogram != nil:
+		for _, e := range m.exemplars {
+			// pb.Histogram.Bucket are sorted by UpperBound.
+			i := sort.Search(len(pb.Histogram.Bucket), func(i int) bool {
+				return pb.Histogram.Bucket[i].GetUpperBound() >= e.GetValue()
+			})
+			if i < len(pb.Histogram.Bucket) {
+				pb.Histogram.Bucket[i].Exemplar = e
+			} else {
+				// This is not possible as last bucket is Inf.
+				panic("no bucket was found for given exemplar value")
+			}
+		}
+	default:
+		// TODO(bwplotka): Implement Gauge?
+		return errors.New("cannot inject exemplar into Gauge, Summary or Untyped")
+	}
+
+	return nil
+}
+
+// Exemplar is easier to use, user-facing representation of *dto.Exemplar.
+type Exemplar struct {
+	Value  float64
+	Labels Labels
+	// Optional.
+	// Default value (time.Time{}) indicates its empty, which should be
+	// understood as time.Now() time at the moment of creation of metric.
+	Timestamp time.Time
+}
+
+// NewMetricWithExemplars returns a new Metric wrapping the provided Metric with given
+// exemplars. Exemplars are validated.
+//
+// Only last applicable exemplar is injected from the list.
+// For example for Counter it means last exemplar is injected.
+// For Histogram, it means last applicable exemplar for each bucket is injected.
+//
+// NewMetricWithExemplars works best with MustNewConstMetric and
+// MustNewConstHistogram, see example.
+func NewMetricWithExemplars(m Metric, exemplars ...Exemplar) (Metric, error) {
+	if len(exemplars) == 0 {
+		return nil, errors.New("no exemplar was passed for NewMetricWithExemplars")
+	}
+
+	var (
+		now = time.Now()
+		exs = make([]*dto.Exemplar, len(exemplars))
+		err error
+	)
+	for i, e := range exemplars {
+		ts := e.Timestamp
+		if ts == (time.Time{}) {
+			ts = now
+		}
+		exs[i], err = newExemplar(e.Value, ts, e.Labels)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return &withExemplarsMetric{Metric: m, exemplars: exs}, nil
+}
+
+// MustNewMetricWithExemplars is a version of NewMetricWithExemplars that panics where
+// NewMetricWithExemplars would have returned an error.
+func MustNewMetricWithExemplars(m Metric, exemplars ...Exemplar) Metric {
+	ret, err := NewMetricWithExemplars(m, exemplars...)
+	if err != nil {
+		panic(err)
+	}
+	return ret
+}
--- a/prometheus/metric_test.go
+++ b/prometheus/metric_test.go
@ -13,7 +13,13 @@

 package prometheus

-import "testing"
+import (
+	"testing"
+
+	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
+	"github.com/golang/protobuf/proto"
+	dto "github.com/prometheus/client_model/go"
+)

 func TestBuildFQName(t *testing.T) {
 	scenarios := []struct{ namespace, subsystem, name, result string }{
@ -33,3 +39,41 @@ func TestBuildFQName(t *testing.T) {
 		}
 	}
 }
+
+func TestWithExemplarsMetric(t *testing.T) {
+	t.Run("histogram", func(t *testing.T) {
+		// Create a constant histogram from values we got from a 3rd party telemetry system.
+		h := MustNewConstHistogram(
+			NewDesc("http_request_duration_seconds", "A histogram of the HTTP request durations.", nil, nil),
+			4711, 403.34,
+			map[float64]uint64{25: 121, 50: 2403, 100: 3221, 200: 4233},
+		)
+
+		m := &withExemplarsMetric{Metric: h, exemplars: []*dto.Exemplar{
+			{Value: proto.Float64(24.0)},
+			{Value: proto.Float64(25.1)},
+			{Value: proto.Float64(42.0)},
+			{Value: proto.Float64(89.0)},
+			{Value: proto.Float64(100.0)},
+			{Value: proto.Float64(157.0)},
+		}}
+		metric := dto.Metric{}
+		if err := m.Write(&metric); err != nil {
+			t.Fatal(err)
+		}
+		if want, got := 4, len(metric.GetHistogram().Bucket); want != got {
+			t.Errorf("want %v, got %v", want, got)
+		}
+
+		expectedExemplarVals := []float64{24.0, 42.0, 100.0, 157.0}
+		for i, b := range metric.GetHistogram().Bucket {
+			if b.Exemplar == nil {
+				t.Errorf("Expected exemplar for bucket %v, got nil", i)
+			}
+			if want, got := expectedExemplarVals[i], *metric.GetHistogram().Bucket[i].Exemplar.Value; want != got {
+				t.Errorf("%v: want %v, got %v", i, want, got)
+			}
+		}
+	})
+
+}
--- a/prometheus/promhttp/http.go
+++ b/prometheus/promhttp/http.go
@ -84,6 +84,13 @@ func Handler() http.Handler {
 // instrumentation. Use the InstrumentMetricHandler function to apply the same
 // kind of instrumentation as it is used by the Handler function.
 func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
+	return HandlerForTransactional(prometheus.ToTransactionalGatherer(reg), opts)
+}
+
+// HandlerForTransactional is like HandlerFor, but it uses transactional gather, which
+// can safely change in-place returned *dto.MetricFamily before call to `Gather` and after
+// call to `done` of that `Gather`.
+func HandlerForTransactional(reg prometheus.TransactionalGatherer, opts HandlerOpts) http.Handler {
 	var (
 		inFlightSem chan struct{}
 		errCnt      = prometheus.NewCounterVec(
@ -123,7 +130,8 @@ func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
 				return
 			}
 		}
-		mfs, err := reg.Gather()
+		mfs, done, err := reg.Gather()
+		defer done()
 		if err != nil {
 			if opts.ErrorLog != nil {
 				opts.ErrorLog.Println("error gathering metrics:", err)
--- a/prometheus/promhttp/http_test.go
+++ b/prometheus/promhttp/http_test.go
@ -16,6 +16,7 @@ package promhttp
 import (
 	"bytes"
 	"errors"
+	"fmt"
 	"log"
 	"net/http"
 	"net/http/httptest"
@ -24,6 +25,7 @@ import (
 	"time"

 	"github.com/prometheus/client_golang/prometheus"
+	dto "github.com/prometheus/client_model/go"
 )

 type errorCollector struct{}
@ -56,8 +58,19 @@ func (b blockingCollector) Collect(ch chan<- prometheus.Metric) {
 	<-b.Block
 }

-func TestHandlerErrorHandling(t *testing.T) {
+type mockTransactionGatherer struct {
+	g             prometheus.Gatherer
+	gatherInvoked int
+	doneInvoked   int
+}

+func (g *mockTransactionGatherer) Gather() (_ []*dto.MetricFamily, done func(), err error) {
+	g.gatherInvoked++
+	mfs, err := g.g.Gather()
+	return mfs, func() { g.doneInvoked++ }, err
+}
+
+func TestHandlerErrorHandling(t *testing.T) {
 	// Create a registry that collects a MetricFamily with two elements,
 	// another with one, and reports an error. Further down, we'll use the
 	// same registry in the HandlerOpts.
@ -90,21 +103,30 @@ func TestHandlerErrorHandling(t *testing.T) {
 	request, _ := http.NewRequest("GET", "/", nil)
 	request.Header.Add("Accept", "test/plain")

-	errorHandler := HandlerFor(reg, HandlerOpts{
+	mReg := &mockTransactionGatherer{g: reg}
+	errorHandler := HandlerForTransactional(mReg, HandlerOpts{
 		ErrorLog:      logger,
 		ErrorHandling: HTTPErrorOnError,
 		Registry:      reg,
 	})
-	continueHandler := HandlerFor(reg, HandlerOpts{
+	continueHandler := HandlerForTransactional(mReg, HandlerOpts{
 		ErrorLog:      logger,
 		ErrorHandling: ContinueOnError,
 		Registry:      reg,
 	})
-	panicHandler := HandlerFor(reg, HandlerOpts{
+	panicHandler := HandlerForTransactional(mReg, HandlerOpts{
 		ErrorLog:      logger,
 		ErrorHandling: PanicOnError,
 		Registry:      reg,
 	})
+	// Expect gatherer not touched.
+	if got := mReg.gatherInvoked; got != 0 {
+		t.Fatalf("unexpected number of gather invokes, want 0, got %d", got)
+	}
+	if got := mReg.doneInvoked; got != 0 {
+		t.Fatalf("unexpected number of done invokes, want 0, got %d", got)
+	}
+
 	wantMsg := `error gathering metrics: error collecting metric Desc{fqName: "invalid_metric", help: "not helpful", constLabels: {}, variableLabels: []}: collect error
 `
 	wantErrorBody := `An error has occurred while serving metrics:
@ -140,25 +162,39 @@ the_count 0
 `

 	errorHandler.ServeHTTP(writer, request)
+	if got := mReg.gatherInvoked; got != 1 {
+		t.Fatalf("unexpected number of gather invokes, want 1, got %d", got)
+	}
+	if got := mReg.doneInvoked; got != 1 {
+		t.Fatalf("unexpected number of done invokes, want 1, got %d", got)
+	}
 	if got, want := writer.Code, http.StatusInternalServerError; got != want {
 		t.Errorf("got HTTP status code %d, want %d", got, want)
 	}
-	if got := logBuf.String(); got != wantMsg {
-		t.Errorf("got log message:\n%s\nwant log message:\n%s\n", got, wantMsg)
+	if got, want := logBuf.String(), wantMsg; got != want {
+		t.Errorf("got log buf %q, want %q", got, want)
 	}
-	if got := writer.Body.String(); got != wantErrorBody {
-		t.Errorf("got body:\n%s\nwant body:\n%s\n", got, wantErrorBody)
+	if got, want := writer.Body.String(), wantErrorBody; got != want {
+		t.Errorf("got body %q, want %q", got, want)
 	}
+
 	logBuf.Reset()
 	writer.Body.Reset()
 	writer.Code = http.StatusOK

 	continueHandler.ServeHTTP(writer, request)
+
+	if got := mReg.gatherInvoked; got != 2 {
+		t.Fatalf("unexpected number of gather invokes, want 2, got %d", got)
+	}
+	if got := mReg.doneInvoked; got != 2 {
+		t.Fatalf("unexpected number of done invokes, want 2, got %d", got)
+	}
 	if got, want := writer.Code, http.StatusOK; got != want {
 		t.Errorf("got HTTP status code %d, want %d", got, want)
 	}
-	if got := logBuf.String(); got != wantMsg {
-		t.Errorf("got log message %q, want %q", got, wantMsg)
+	if got, want := logBuf.String(), wantMsg; got != want {
+		t.Errorf("got log buf %q, want %q", got, want)
 	}
 	if got := writer.Body.String(); got != wantOKBody1 && got != wantOKBody2 {
 		t.Errorf("got body %q, want either %q or %q", got, wantOKBody1, wantOKBody2)
@ -168,20 +204,34 @@ the_count 0
 		if err := recover(); err == nil {
 			t.Error("expected panic from panicHandler")
 		}
+		if got := mReg.gatherInvoked; got != 3 {
+			t.Fatalf("unexpected number of gather invokes, want 3, got %d", got)
+		}
+		if got := mReg.doneInvoked; got != 3 {
+			t.Fatalf("unexpected number of done invokes, want 3, got %d", got)
+		}
 	}()
 	panicHandler.ServeHTTP(writer, request)
 }

 func TestInstrumentMetricHandler(t *testing.T) {
 	reg := prometheus.NewRegistry()
-	handler := InstrumentMetricHandler(reg, HandlerFor(reg, HandlerOpts{}))
+	mReg := &mockTransactionGatherer{g: reg}
+	handler := InstrumentMetricHandler(reg, HandlerForTransactional(mReg, HandlerOpts{}))
 	// Do it again to test idempotency.
-	InstrumentMetricHandler(reg, HandlerFor(reg, HandlerOpts{}))
+	InstrumentMetricHandler(reg, HandlerForTransactional(mReg, HandlerOpts{}))
 	writer := httptest.NewRecorder()
 	request, _ := http.NewRequest("GET", "/", nil)
 	request.Header.Add("Accept", "test/plain")

 	handler.ServeHTTP(writer, request)
+	if got := mReg.gatherInvoked; got != 1 {
+		t.Fatalf("unexpected number of gather invokes, want 1, got %d", got)
+	}
+	if got := mReg.doneInvoked; got != 1 {
+		t.Fatalf("unexpected number of done invokes, want 1, got %d", got)
+	}
+
 	if got, want := writer.Code, http.StatusOK; got != want {
 		t.Errorf("got HTTP status code %d, want %d", got, want)
 	}
@ -195,19 +245,28 @@ func TestInstrumentMetricHandler(t *testing.T) {
 		t.Errorf("got body %q, does not contain %q", got, want)
 	}

-	writer.Body.Reset()
-	handler.ServeHTTP(writer, request)
-	if got, want := writer.Code, http.StatusOK; got != want {
-		t.Errorf("got HTTP status code %d, want %d", got, want)
-	}
+	for i := 0; i < 100; i++ {
+		writer.Body.Reset()
+		handler.ServeHTTP(writer, request)

-	want = "promhttp_metric_handler_requests_in_flight 1\n"
-	if got := writer.Body.String(); !strings.Contains(got, want) {
-		t.Errorf("got body %q, does not contain %q", got, want)
-	}
-	want = "promhttp_metric_handler_requests_total{code=\"200\"} 1\n"
-	if got := writer.Body.String(); !strings.Contains(got, want) {
-		t.Errorf("got body %q, does not contain %q", got, want)
+		if got, want := mReg.gatherInvoked, i+2; got != want {
+			t.Fatalf("unexpected number of gather invokes, want %d, got %d", want, got)
+		}
+		if got, want := mReg.doneInvoked, i+2; got != want {
+			t.Fatalf("unexpected number of done invokes, want %d, got %d", want, got)
+		}
+		if got, want := writer.Code, http.StatusOK; got != want {
+			t.Errorf("got HTTP status code %d, want %d", got, want)
+		}
+
+		want := "promhttp_metric_handler_requests_in_flight 1\n"
+		if got := writer.Body.String(); !strings.Contains(got, want) {
+			t.Errorf("got body %q, does not contain %q", got, want)
+		}
+		want = fmt.Sprintf("promhttp_metric_handler_requests_total{code=\"200\"} %d\n", i+1)
+		if got := writer.Body.String(); !strings.Contains(got, want) {
+			t.Errorf("got body %q, does not contain %q", got, want)
+		}
 	}
 }

--- a/prometheus/push/push.go
+++ b/prometheus/push/push.go
@ -36,6 +36,7 @@ package push

 import (
 	"bytes"
+	"context"
 	"encoding/base64"
 	"errors"
 	"fmt"
@ -123,14 +124,28 @@ func New(url, job string) *Pusher {
 // Push returns the first error encountered by any method call (including this
 // one) in the lifetime of the Pusher.
 func (p *Pusher) Push() error {
-	return p.push(http.MethodPut)
+	return p.push(context.Background(), http.MethodPut)
+}
+
+// PushContext is like Push but includes a context.
+//
+// If the context expires before HTTP request is complete, an error is returned.
+func (p *Pusher) PushContext(ctx context.Context) error {
+	return p.push(ctx, http.MethodPut)
 }

 // Add works like push, but only previously pushed metrics with the same name
 // (and the same job and other grouping labels) will be replaced. (It uses HTTP
 // method “POST” to push to the Pushgateway.)
 func (p *Pusher) Add() error {
-	return p.push(http.MethodPost)
+	return p.push(context.Background(), http.MethodPost)
+}
+
+// AddContext is like Add but includes a context.
+//
+// If the context expires before HTTP request is complete, an error is returned.
+func (p *Pusher) AddContext(ctx context.Context) error {
+	return p.push(ctx, http.MethodPost)
 }

 // Gatherer adds a Gatherer to the Pusher, from which metrics will be gathered
@ -233,7 +248,7 @@ func (p *Pusher) Delete() error {
 	return nil
 }

-func (p *Pusher) push(method string) error {
+func (p *Pusher) push(ctx context.Context, method string) error {
 	if p.error != nil {
 		return p.error
 	}
@ -260,7 +275,7 @@ func (p *Pusher) push(method string) error {
 		}
 		enc.Encode(mf)
 	}
-	req, err := http.NewRequest(method, p.fullURL(), buf)
+	req, err := http.NewRequestWithContext(ctx, method, p.fullURL(), buf)
 	if err != nil {
 		return err
 	}
--- a/prometheus/registry.go
+++ b/prometheus/registry.go
@ -407,6 +407,14 @@ func (r *Registry) MustRegister(cs ...Collector) {

 // Gather implements Gatherer.
 func (r *Registry) Gather() ([]*dto.MetricFamily, error) {
+	r.mtx.RLock()
+
+	if len(r.collectorsByID) == 0 && len(r.uncheckedCollectors) == 0 {
+		// Fast path.
+		r.mtx.RUnlock()
+		return nil, nil
+	}
+
 	var (
 		checkedMetricChan   = make(chan Metric, capMetricChan)
 		uncheckedMetricChan = make(chan Metric, capMetricChan)
@ -416,7 +424,6 @@ func (r *Registry) Gather() ([]*dto.MetricFamily, error) {
 		registeredDescIDs   map[uint64]struct{} // Only used for pedantic checks
 	)

-	r.mtx.RLock()
 	goroutineBudget := len(r.collectorsByID) + len(r.uncheckedCollectors)
 	metricFamiliesByName := make(map[string]*dto.MetricFamily, len(r.dimHashesByName))
 	checkedCollectors := make(chan Collector, len(r.collectorsByID))
@ -884,11 +891,11 @@ func checkMetricConsistency(
 	h.Write(separatorByteSlice)
 	// Make sure label pairs are sorted. We depend on it for the consistency
 	// check.
-	if !sort.IsSorted(labelPairSorter(dtoMetric.Label)) {
+	if !sort.IsSorted(internal.LabelPairSorter(dtoMetric.Label)) {
 		// We cannot sort dtoMetric.Label in place as it is immutable by contract.
 		copiedLabels := make([]*dto.LabelPair, len(dtoMetric.Label))
 		copy(copiedLabels, dtoMetric.Label)
-		sort.Sort(labelPairSorter(copiedLabels))
+		sort.Sort(internal.LabelPairSorter(copiedLabels))
 		dtoMetric.Label = copiedLabels
 	}
 	for _, lp := range dtoMetric.Label {
@ -935,7 +942,7 @@ func checkDescConsistency(
 			metricFamily.GetName(), dtoMetric, desc,
 		)
 	}
-	sort.Sort(labelPairSorter(lpsFromDesc))
+	sort.Sort(internal.LabelPairSorter(lpsFromDesc))
 	for i, lpFromDesc := range lpsFromDesc {
 		lpFromMetric := dtoMetric.Label[i]
 		if lpFromDesc.GetName() != lpFromMetric.GetName() ||
@ -948,3 +955,89 @@ func checkDescConsistency(
 	}
 	return nil
 }
+
+var _ TransactionalGatherer = &MultiTRegistry{}
+
+// MultiTRegistry is a TransactionalGatherer that joins gathered metrics from multiple
+// transactional gatherers.
+//
+// It is caller responsibility to ensure two registries have mutually exclusive metric families,
+// no deduplication will happen.
+type MultiTRegistry struct {
+	tGatherers []TransactionalGatherer
+}
+
+// NewMultiTRegistry creates MultiTRegistry.
+func NewMultiTRegistry(tGatherers ...TransactionalGatherer) *MultiTRegistry {
+	return &MultiTRegistry{
+		tGatherers: tGatherers,
+	}
+}
+
+// Gather implements TransactionalGatherer interface.
+func (r *MultiTRegistry) Gather() (mfs []*dto.MetricFamily, done func(), err error) {
+	errs := MultiError{}
+
+	dFns := make([]func(), 0, len(r.tGatherers))
+	// TODO(bwplotka): Implement concurrency for those?
+	for _, g := range r.tGatherers {
+		// TODO(bwplotka): Check for duplicates?
+		m, d, err := g.Gather()
+		errs.Append(err)
+
+		mfs = append(mfs, m...)
+		dFns = append(dFns, d)
+	}
+
+	// TODO(bwplotka): Consider sort in place, given metric family in gather is sorted already.
+	sort.Slice(mfs, func(i, j int) bool {
+		return *mfs[i].Name < *mfs[j].Name
+	})
+	return mfs, func() {
+		for _, d := range dFns {
+			d()
+		}
+	}, errs.MaybeUnwrap()
+}
+
+// TransactionalGatherer represents transactional gatherer that can be triggered to notify gatherer that memory
+// used by metric family is no longer used by a caller. This allows implementations with cache.
+type TransactionalGatherer interface {
+	// Gather returns metrics in a lexicographically sorted slice
+	// of uniquely named MetricFamily protobufs. Gather ensures that the
+	// returned slice is valid and self-consistent so that it can be used
+	// for valid exposition. As an exception to the strict consistency
+	// requirements described for metric.Desc, Gather will tolerate
+	// different sets of label names for metrics of the same metric family.
+	//
+	// Even if an error occurs, Gather attempts to gather as many metrics as
+	// possible. Hence, if a non-nil error is returned, the returned
+	// MetricFamily slice could be nil (in case of a fatal error that
+	// prevented any meaningful metric collection) or contain a number of
+	// MetricFamily protobufs, some of which might be incomplete, and some
+	// might be missing altogether. The returned error (which might be a
+	// MultiError) explains the details. Note that this is mostly useful for
+	// debugging purposes. If the gathered protobufs are to be used for
+	// exposition in actual monitoring, it is almost always better to not
+	// expose an incomplete result and instead disregard the returned
+	// MetricFamily protobufs in case the returned error is non-nil.
+	//
+	// Important: done is expected to be triggered (even if the error occurs!)
+	// once caller does not need returned slice of dto.MetricFamily.
+	Gather() (_ []*dto.MetricFamily, done func(), err error)
+}
+
+// ToTransactionalGatherer transforms Gatherer to transactional one with noop as done function.
+func ToTransactionalGatherer(g Gatherer) TransactionalGatherer {
+	return &noTransactionGatherer{g: g}
+}
+
+type noTransactionGatherer struct {
+	g Gatherer
+}
+
+// Gather implements TransactionalGatherer interface.
+func (g *noTransactionGatherer) Gather() (_ []*dto.MetricFamily, done func(), err error) {
+	mfs, err := g.g.Gather()
+	return mfs, func() {}, err
+}
--- a/prometheus/registry_test.go
+++ b/prometheus/registry_test.go
@ -21,6 +21,7 @@ package prometheus_test

 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"math/rand"
@ -1175,3 +1176,82 @@ func TestAlreadyRegisteredCollision(t *testing.T) {
 		}
 	}
 }
+
+type tGatherer struct {
+	done bool
+	err  error
+}
+
+func (g *tGatherer) Gather() (_ []*dto.MetricFamily, done func(), err error) {
+	name := "g1"
+	val := 1.0
+	return []*dto.MetricFamily{
+		{Name: &name, Metric: []*dto.Metric{{Gauge: &dto.Gauge{Value: &val}}}},
+	}, func() { g.done = true }, g.err
+}
+
+func TestNewMultiTRegistry(t *testing.T) {
+	treg := &tGatherer{}
+
+	t.Run("one registry", func(t *testing.T) {
+		m := prometheus.NewMultiTRegistry(treg)
+		ret, done, err := m.Gather()
+		if err != nil {
+			t.Error("gather failed:", err)
+		}
+		done()
+		if len(ret) != 1 {
+			t.Error("unexpected number of metric families, expected 1, got", ret)
+		}
+		if !treg.done {
+			t.Error("inner transactional registry not marked as done")
+		}
+	})
+
+	reg := prometheus.NewRegistry()
+	if err := reg.Register(prometheus.NewCounter(prometheus.CounterOpts{Name: "c1", Help: "help c1"})); err != nil {
+		t.Error("registration failed:", err)
+	}
+
+	// Note on purpose two registries will have exactly same metric family name (but with different string).
+	// This behaviour is undefined at the moment.
+	if err := reg.Register(prometheus.NewGauge(prometheus.GaugeOpts{Name: "g1", Help: "help g1"})); err != nil {
+		t.Error("registration failed:", err)
+	}
+	treg.done = false
+
+	t.Run("two registries", func(t *testing.T) {
+		m := prometheus.NewMultiTRegistry(prometheus.ToTransactionalGatherer(reg), treg)
+		ret, done, err := m.Gather()
+		if err != nil {
+			t.Error("gather failed:", err)
+		}
+		done()
+		if len(ret) != 3 {
+			t.Error("unexpected number of metric families, expected 3, got", ret)
+		}
+		if !treg.done {
+			t.Error("inner transactional registry not marked as done")
+		}
+	})
+
+	treg.done = false
+	// Inject error.
+	treg.err = errors.New("test err")
+
+	t.Run("two registries, one with error", func(t *testing.T) {
+		m := prometheus.NewMultiTRegistry(prometheus.ToTransactionalGatherer(reg), treg)
+		ret, done, err := m.Gather()
+		if err != treg.err {
+			t.Error("unexpected error:", err)
+		}
+		done()
+		if len(ret) != 3 {
+			t.Error("unexpected number of metric families, expected 3, got", ret)
+		}
+		// Still on error, we expect done to be triggered.
+		if !treg.done {
+			t.Error("inner transactional registry not marked as done")
+		}
+	})
+}
--- a/prometheus/testutil/testutil.go
+++ b/prometheus/testutil/testutil.go
@ -41,7 +41,9 @@ import (
 	"bytes"
 	"fmt"
 	"io"
+	"reflect"

+	"github.com/davecgh/go-spew/spew"
 	"github.com/prometheus/common/expfmt"

 	dto "github.com/prometheus/client_model/go"
@ -167,7 +169,16 @@ func CollectAndCompare(c prometheus.Collector, expected io.Reader, metricNames .
 // exposition format. If any metricNames are provided, only metrics with those
 // names are compared.
 func GatherAndCompare(g prometheus.Gatherer, expected io.Reader, metricNames ...string) error {
-	got, err := g.Gather()
+	return TransactionalGatherAndCompare(prometheus.ToTransactionalGatherer(g), expected, metricNames...)
+}
+
+// TransactionalGatherAndCompare gathers all metrics from the provided Gatherer and compares
+// it to an expected output read from the provided Reader in the Prometheus text
+// exposition format. If any metricNames are provided, only metrics with those
+// names are compared.
+func TransactionalGatherAndCompare(g prometheus.TransactionalGatherer, expected io.Reader, metricNames ...string) error {
+	got, done, err := g.Gather()
+	defer done()
 	if err != nil {
 		return fmt.Errorf("gathering metrics failed: %s", err)
 	}
@ -202,20 +213,73 @@ func compare(got, want []*dto.MetricFamily) error {
 			return fmt.Errorf("encoding expected metrics failed: %s", err)
 		}
 	}
-
-	if wantBuf.String() != gotBuf.String() {
-		return fmt.Errorf(`
-metric output does not match expectation; want:
-
-%s
-got:
-
-%s`, wantBuf.String(), gotBuf.String())
-
+	if diffErr := diff(wantBuf, gotBuf); diffErr != "" {
+		return fmt.Errorf(diffErr)
 	}
 	return nil
 }

+// diff returns a diff of both values as long as both are of the same type and
+// are a struct, map, slice, array or string. Otherwise it returns an empty string.
+func diff(expected interface{}, actual interface{}) string {
+	if expected == nil || actual == nil {
+		return ""
+	}
+
+	et, ek := typeAndKind(expected)
+	at, _ := typeAndKind(actual)
+	if et != at {
+		return ""
+	}
+
+	if ek != reflect.Struct && ek != reflect.Map && ek != reflect.Slice && ek != reflect.Array && ek != reflect.String {
+		return ""
+	}
+
+	var e, a string
+	c := spew.ConfigState{
+		Indent:                  " ",
+		DisablePointerAddresses: true,
+		DisableCapacities:       true,
+		SortKeys:                true,
+	}
+	if et != reflect.TypeOf("") {
+		e = c.Sdump(expected)
+		a = c.Sdump(actual)
+	} else {
+		e = reflect.ValueOf(expected).String()
+		a = reflect.ValueOf(actual).String()
+	}
+
+	diff, _ := internal.GetUnifiedDiffString(internal.UnifiedDiff{
+		A:        internal.SplitLines(e),
+		B:        internal.SplitLines(a),
+		FromFile: "metric output does not match expectation; want",
+		FromDate: "",
+		ToFile:   "got:",
+		ToDate:   "",
+		Context:  1,
+	})
+
+	if diff == "" {
+		return ""
+	}
+
+	return "\n\nDiff:\n" + diff
+}
+
+// typeAndKind returns the type and kind of the given interface{}
+func typeAndKind(v interface{}) (reflect.Type, reflect.Kind) {
+	t := reflect.TypeOf(v)
+	k := t.Kind()
+
+	if k == reflect.Ptr {
+		t = t.Elem()
+		k = t.Kind()
+	}
+	return t, k
+}
+
 func filterMetrics(metrics []*dto.MetricFamily, names []string) []*dto.MetricFamily {
 	var filtered []*dto.MetricFamily
 	for _, m := range metrics {
--- a/prometheus/testutil/testutil_test.go
+++ b/prometheus/testutil/testutil_test.go
@ -284,17 +284,18 @@ func TestMetricNotFound(t *testing.T) {
 	`

 	expectedError := `
-metric output does not match expectation; want:

-# HELP some_other_metric A value that represents a counter.
-# TYPE some_other_metric counter
-some_other_metric{label1="value1"} 1
-
-got:
-
-# HELP some_total A value that represents a counter.
-# TYPE some_total counter
-some_total{label1="value1"} 1
+Diff:
+--- metric output does not match expectation; want
+++ got:
+@@ -1,4 +1,4 @@
+-(bytes.Buffer) # HELP some_other_metric A value that represents a counter.
+-# TYPE some_other_metric counter
+-some_other_metric{label1="value1"} 1
+(bytes.Buffer) # HELP some_total A value that represents a counter.
+# TYPE some_total counter
+some_total{label1="value1"} 1
+ 
 `

 	err := CollectAndCompare(c, strings.NewReader(metadata+expected))
--- a/prometheus/value.go
+++ b/prometheus/value.go
@ -21,6 +21,7 @@ import (

 	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
 	"github.com/golang/protobuf/proto"
+	"github.com/prometheus/client_golang/prometheus/internal"
 	"google.golang.org/protobuf/types/known/timestamppb"

 	dto "github.com/prometheus/client_model/go"
@ -38,6 +39,23 @@ const (
 	UntypedValue
 )

+var (
+	CounterMetricTypePtr = func() *dto.MetricType { d := dto.MetricType_COUNTER; return &d }()
+	GaugeMetricTypePtr   = func() *dto.MetricType { d := dto.MetricType_GAUGE; return &d }()
+	UntypedMetricTypePtr = func() *dto.MetricType { d := dto.MetricType_UNTYPED; return &d }()
+)
+
+func (v ValueType) ToDTO() *dto.MetricType {
+	switch v {
+	case CounterValue:
+		return CounterMetricTypePtr
+	case GaugeValue:
+		return GaugeMetricTypePtr
+	default:
+		return UntypedMetricTypePtr
+	}
+}
+
 // valueFunc is a generic metric for simple values retrieved on collect time
 // from a function. It implements Metric and Collector. Its effective type is
 // determined by ValueType. This is a low-level building block used by the
@ -91,11 +109,15 @@ func NewConstMetric(desc *Desc, valueType ValueType, value float64, labelValues
 	if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil {
 		return nil, err
 	}
+
+	metric := &dto.Metric{}
+	if err := populateMetric(valueType, value, MakeLabelPairs(desc, labelValues), nil, metric); err != nil {
+		return nil, err
+	}
+
 	return &constMetric{
-		desc:       desc,
-		valType:    valueType,
-		val:        value,
-		labelPairs: MakeLabelPairs(desc, labelValues),
+		desc:   desc,
+		metric: metric,
 	}, nil
 }

@ -110,10 +132,8 @@ func MustNewConstMetric(desc *Desc, valueType ValueType, value float64, labelVal
 }

 type constMetric struct {
-	desc       *Desc
-	valType    ValueType
-	val        float64
-	labelPairs []*dto.LabelPair
+	desc   *Desc
+	metric *dto.Metric
 }

 func (m *constMetric) Desc() *Desc {
@ -121,7 +141,11 @@ func (m *constMetric) Desc() *Desc {
 }

 func (m *constMetric) Write(out *dto.Metric) error {
-	return populateMetric(m.valType, m.val, m.labelPairs, nil, out)
+	out.Label = m.metric.Label
+	out.Counter = m.metric.Counter
+	out.Gauge = m.metric.Gauge
+	out.Untyped = m.metric.Untyped
+	return nil
 }

 func populateMetric(
@ -170,7 +194,7 @@ func MakeLabelPairs(desc *Desc, labelValues []string) []*dto.LabelPair {
 		})
 	}
 	labelPairs = append(labelPairs, desc.constLabelPairs...)
-	sort.Sort(labelPairSorter(labelPairs))
+	sort.Sort(internal.LabelPairSorter(labelPairs))
 	return labelPairs
 }

--- a/prometheus/vec.go
+++ b/prometheus/vec.go
@ -99,6 +99,16 @@ func (m *MetricVec) Delete(labels Labels) bool {
 	return m.metricMap.deleteByHashWithLabels(h, labels, m.curry)
 }

+// DeletePartialMatch deletes all metrics where the variable labels contain all of those
+// passed in as labels. The order of the labels does not matter.
+// It returns the number of metrics deleted.
+//
+// Note that curried labels will never be matched if deleting from the curried vector.
+// To match curried labels with DeletePartialMatch, it must be called on the base vector.
+func (m *MetricVec) DeletePartialMatch(labels Labels) int {
+	return m.metricMap.deleteByLabels(labels, m.curry)
+}
+
 // Without explicit forwarding of Describe, Collect, Reset, those methods won't
 // show up in GoDoc.

@ -381,6 +391,82 @@ func (m *metricMap) deleteByHashWithLabels(
 	return true
 }

+// deleteByLabels deletes a metric if the given labels are present in the metric.
+func (m *metricMap) deleteByLabels(labels Labels, curry []curriedLabelValue) int {
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+
+	var numDeleted int
+
+	for h, metrics := range m.metrics {
+		i := findMetricWithPartialLabels(m.desc, metrics, labels, curry)
+		if i >= len(metrics) {
+			// Didn't find matching labels in this metric slice.
+			continue
+		}
+		delete(m.metrics, h)
+		numDeleted++
+	}
+
+	return numDeleted
+}
+
+// findMetricWithPartialLabel returns the index of the matching metric or
+// len(metrics) if not found.
+func findMetricWithPartialLabels(
+	desc *Desc, metrics []metricWithLabelValues, labels Labels, curry []curriedLabelValue,
+) int {
+	for i, metric := range metrics {
+		if matchPartialLabels(desc, metric.values, labels, curry) {
+			return i
+		}
+	}
+	return len(metrics)
+}
+
+// indexOf searches the given slice of strings for the target string and returns
+// the index or len(items) as well as a boolean whether the search succeeded.
+func indexOf(target string, items []string) (int, bool) {
+	for i, l := range items {
+		if l == target {
+			return i, true
+		}
+	}
+	return len(items), false
+}
+
+// valueMatchesVariableOrCurriedValue determines if a value was previously curried,
+// and returns whether it matches either the "base" value or the curried value accordingly.
+// It also indicates whether the match is against a curried or uncurried value.
+func valueMatchesVariableOrCurriedValue(targetValue string, index int, values []string, curry []curriedLabelValue) (bool, bool) {
+	for _, curriedValue := range curry {
+		if curriedValue.index == index {
+			// This label was curried. See if the curried value matches our target.
+			return curriedValue.value == targetValue, true
+		}
+	}
+	// This label was not curried. See if the current value matches our target label.
+	return values[index] == targetValue, false
+}
+
+// matchPartialLabels searches the current metric and returns whether all of the target label:value pairs are present.
+func matchPartialLabels(desc *Desc, values []string, labels Labels, curry []curriedLabelValue) bool {
+	for l, v := range labels {
+		// Check if the target label exists in our metrics and get the index.
+		varLabelIndex, validLabel := indexOf(l, desc.variableLabels)
+		if validLabel {
+			// Check the value of that label against the target value.
+			// We don't consider curried values in partial matches.
+			matches, curried := valueMatchesVariableOrCurriedValue(v, varLabelIndex, values, curry)
+			if matches && !curried {
+				continue
+			}
+		}
+		return false
+	}
+	return true
+}
+
 // getOrCreateMetricWithLabelValues retrieves the metric by hash and label value
 // or creates it and returns the new one.
 //
--- a/prometheus/vec_test.go
+++ b/prometheus/vec_test.go
@ -125,6 +125,93 @@ func testDeleteLabelValues(t *testing.T, vec *GaugeVec) {
 	}
 }

+func TestDeletePartialMatch(t *testing.T) {
+	baseVec := NewGaugeVec(
+		GaugeOpts{
+			Name: "test",
+			Help: "helpless",
+		},
+		[]string{"l1", "l2", "l3"},
+	)
+
+	assertNoMetric := func(t *testing.T) {
+		if n := len(baseVec.metricMap.metrics); n != 0 {
+			t.Error("expected no metrics, got", n)
+		}
+	}
+
+	// No metric value is set.
+	if got, want := baseVec.DeletePartialMatch(Labels{"l1": "v1", "l2": "v2"}), 0; got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+
+	baseVec.With(Labels{"l1": "baseValue1", "l2": "baseValue2", "l3": "baseValue3"}).Inc()
+	baseVec.With(Labels{"l1": "multiDeleteV1", "l2": "diff1BaseValue2", "l3": "v3"}).(Gauge).Set(42)
+	baseVec.With(Labels{"l1": "multiDeleteV1", "l2": "diff2BaseValue2", "l3": "v3"}).(Gauge).Set(84)
+	baseVec.With(Labels{"l1": "multiDeleteV1", "l2": "diff3BaseValue2", "l3": "v3"}).(Gauge).Set(168)
+
+	curriedVec := baseVec.MustCurryWith(Labels{"l2": "curriedValue2"})
+	curriedVec.WithLabelValues("curriedValue1", "curriedValue3").Inc()
+	curriedVec.WithLabelValues("curriedValue1", "differentCurriedValue3").Inc()
+	curriedVec.WithLabelValues("differentCurriedValue1", "differentCurriedValue3").Inc()
+
+	// Try to delete nonexistent label with existent value from curried vector.
+	if got, want := curriedVec.DeletePartialMatch(Labels{"lx": "curriedValue1"}), 0; got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+
+	// Try to delete valid label with nonexistent value from curried vector.
+	if got, want := curriedVec.DeletePartialMatch(Labels{"l1": "badValue1"}), 0; got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+
+	// Try to delete from a curried vector based on labels which were curried.
+	// This operation succeeds when run against the base vector below.
+	if got, want := curriedVec.DeletePartialMatch(Labels{"l2": "curriedValue2"}), 0; got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+
+	// Try to delete from a curried vector based on labels which were curried,
+	// but the value actually exists in the base vector.
+	if got, want := curriedVec.DeletePartialMatch(Labels{"l2": "baseValue2"}), 0; got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+
+	// Delete multiple matching metrics from a curried vector based on partial values.
+	if got, want := curriedVec.DeletePartialMatch(Labels{"l1": "curriedValue1"}), 2; got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+
+	// Try to delete nonexistent label with existent value from base vector.
+	if got, want := baseVec.DeletePartialMatch(Labels{"lx": "curriedValue1"}), 0; got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+
+	// Try to delete partially invalid labels from base vector.
+	if got, want := baseVec.DeletePartialMatch(Labels{"l1": "baseValue1", "l2": "badValue2"}), 0; got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+
+	// Delete from the base vector based on values which were curried.
+	// This operation fails when run against a curried vector above.
+	if got, want := baseVec.DeletePartialMatch(Labels{"l2": "curriedValue2"}), 1; got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+
+	// Delete multiple metrics from the base vector based on a single valid label.
+	if got, want := baseVec.DeletePartialMatch(Labels{"l1": "multiDeleteV1"}), 3; got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+
+	// Delete from the base vector based on values which were not curried.
+	if got, want := baseVec.DeletePartialMatch(Labels{"l3": "baseValue3"}), 1; got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+
+	// All metrics should have been deleted now.
+	assertNoMetric(t)
+}
+
 func TestMetricVec(t *testing.T) {
 	vec := NewGaugeVec(
 		GaugeOpts{
--- a/prometheus/wrap.go
+++ b/prometheus/wrap.go
@ -20,6 +20,7 @@ import (
 	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
 	"github.com/golang/protobuf/proto"

+	"github.com/prometheus/client_golang/prometheus/internal"
 	dto "github.com/prometheus/client_model/go"
 )

@ -182,7 +183,7 @@ func (m *wrappingMetric) Write(out *dto.Metric) error {
 			Value: proto.String(lv),
 		})
 	}
-	sort.Sort(labelPairSorter(out.Label))
+	sort.Sort(internal.LabelPairSorter(out.Label))
 	return nil
 }