test: vet that all Cmders have a SetVal() method

Makefile

@@ -6,6 +6,8 @@ test: testdeps
 	go test ./... -run=NONE -bench=. -benchmem
 	env GOOS=linux GOARCH=386 go test ./...
 	go vet
+	cd internal/customvet && go build .
+	go vet -vettool ./internal/customvet/customvet
 
 testdeps: testdata/redis/src/redis-server
 

internal/customvet/.gitignore

@@ -0,0 +1 @@
+/customvet

internal/customvet/checks/setval/setval.go

@@ -0,0 +1,61 @@
+package setval
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+	"golang.org/x/tools/go/analysis"
+)
+
+var Analyzer = &analysis.Analyzer{
+	Name: "setval",
+	Doc:  "find Cmder types that are missing a SetVal method",
+
+	Run: func(pass *analysis.Pass) (interface{}, error) {
+		cmderTypes := make(map[string]token.Pos)
+		typesWithSetValMethod := make(map[string]bool)
+
+		for _, file := range pass.Files {
+			for _, decl := range file.Decls {
+				funcName, receiverType := parseFuncDecl(decl, pass.TypesInfo)
+
+				switch funcName {
+				case "Result":
+					cmderTypes[receiverType] = decl.Pos()
+				case "SetVal":
+					typesWithSetValMethod[receiverType] = true
+				}
+			}
+		}
+
+		for cmder, pos := range cmderTypes {
+			if !typesWithSetValMethod[cmder] {
+				pass.Reportf(pos, "%s is missing a SetVal method", cmder)
+			}
+		}
+
+		return nil, nil
+	},
+}
+
+func parseFuncDecl(decl ast.Decl, typesInfo *types.Info) (funcName, receiverType string) {
+	funcDecl, ok := decl.(*ast.FuncDecl)
+	if !ok {
+		return "", "" // Not a function declaration.
+	}
+
+	if funcDecl.Recv == nil {
+		return "", "" // Not a method.
+	}
+
+	if len(funcDecl.Recv.List) != 1 {
+		return "", "" // Unexpected number of receiver arguments. (Can this happen?)
+	}
+
+	receiverTypeObj := typesInfo.TypeOf(funcDecl.Recv.List[0].Type)
+	if receiverTypeObj == nil {
+		return "", "" // Unable to determine the receiver type.
+	}
+
+	return funcDecl.Name.Name, receiverTypeObj.String()
+}

internal/customvet/checks/setval/setval_test.go

@@ -0,0 +1,12 @@
+package setval_test
+
+import (
+	"github.com/go-redis/redis/internal/customvet/checks/setval"
+	"golang.org/x/tools/go/analysis/analysistest"
+	"testing"
+)
+
+func Test(t *testing.T) {
+	testdata := analysistest.TestData()
+	analysistest.Run(t, testdata, setval.Analyzer, "a")
+}

internal/customvet/checks/setval/testdata/src/a/a.go

@@ -0,0 +1,29 @@
+package a
+
+type GoodCmd struct {
+	val int
+}
+
+func (c *GoodCmd) SetVal(val int) {
+	c.val = val
+}
+
+func (c *GoodCmd) Result() (int, error) {
+	return c.val, nil
+}
+
+type BadCmd struct {
+	val int
+}
+
+func (c *BadCmd) Result() (int, error) { // want "\\*a.BadCmd is missing a SetVal method"
+	return c.val, nil
+}
+
+type NotACmd struct {
+	val int
+}
+
+func (c *NotACmd) Val() int {
+	return c.val
+}

internal/customvet/go.mod

@@ -0,0 +1,10 @@
+module github.com/go-redis/redis/internal/customvet
+
+go 1.17
+
+require golang.org/x/tools v0.1.12
+
+require (
+	golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4 // indirect
+	golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f // indirect
+)

internal/customvet/go.sum

@@ -0,0 +1,26 @@
+github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
+golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4 h1:6zppjxzCulZykYSLyVDYbneBfbaBIQPYMevg0bEwv2s=
+golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
+golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f h1:v4INt8xihDGvnrfjMDVXGxw9wrfxYyCjk0KbXjhR55s=
+golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.1.12 h1:VveCTK38A2rkS8ZqFY25HIDFscX5X9OoEhJd3quQmXU=
+golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

internal/customvet/main.go

@@ -0,0 +1,12 @@
+package main
+
+import (
+	"github.com/go-redis/redis/internal/customvet/checks/setval"
+	"golang.org/x/tools/go/analysis/multichecker"
+)
+
+func main() {
+	multichecker.Main(
+		setval.Analyzer,
+	)
+}