From e7ef5df93df7c392e0337afa8b5ac23b8276bf4c Mon Sep 17 00:00:00 2001
From: Lukas Vogel <vogel@anapaya.net>
Date: Thu, 5 Sep 2024 15:01:23 +0200
Subject: [PATCH] registry: drop duplicate checks

In processMetrics drop duplicate checks. If the metricFamily exists we
already have a type check with the call to checkMetricConsistency. The
help string is already checked in the checkDescConsistency albeit only
if pedantic mode is enabled. However this is probably what is desired
anyway.
---
 prometheus/registry.go | 49 +-----------------------------------------
 1 file changed, 1 insertion(+), 48 deletions(-)

diff --git a/prometheus/registry.go b/prometheus/registry.go
index c6fd2f5..c5d3af6 100644
--- a/prometheus/registry.go
+++ b/prometheus/registry.go
@@ -634,54 +634,7 @@ func processMetric(
 		return fmt.Errorf("error collecting metric %v: %w", desc, err)
 	}
 	metricFamily, ok := metricFamiliesByName[desc.fqName]
-	if ok { // Existing name.
-		if metricFamily.GetHelp() != desc.help {
-			return fmt.Errorf(
-				"collected metric %s %s has help %q but should have %q",
-				desc.fqName, dtoMetric, desc.help, metricFamily.GetHelp(),
-			)
-		}
-		// TODO(beorn7): Simplify switch once Desc has type.
-		switch metricFamily.GetType() {
-		case dto.MetricType_COUNTER:
-			if dtoMetric.Counter == nil {
-				return fmt.Errorf(
-					"collected metric %s %s should be a Counter",
-					desc.fqName, dtoMetric,
-				)
-			}
-		case dto.MetricType_GAUGE:
-			if dtoMetric.Gauge == nil {
-				return fmt.Errorf(
-					"collected metric %s %s should be a Gauge",
-					desc.fqName, dtoMetric,
-				)
-			}
-		case dto.MetricType_SUMMARY:
-			if dtoMetric.Summary == nil {
-				return fmt.Errorf(
-					"collected metric %s %s should be a Summary",
-					desc.fqName, dtoMetric,
-				)
-			}
-		case dto.MetricType_UNTYPED:
-			if dtoMetric.Untyped == nil {
-				return fmt.Errorf(
-					"collected metric %s %s should be Untyped",
-					desc.fqName, dtoMetric,
-				)
-			}
-		case dto.MetricType_HISTOGRAM:
-			if dtoMetric.Histogram == nil {
-				return fmt.Errorf(
-					"collected metric %s %s should be a Histogram",
-					desc.fqName, dtoMetric,
-				)
-			}
-		default:
-			panic("encountered MetricFamily with invalid type")
-		}
-	} else { // New name.
+	if !ok { // New name.
 		metricFamily = &dto.MetricFamily{}
 		metricFamily.Name = proto.String(desc.fqName)
 		metricFamily.Help = proto.String(desc.help)