mirror: linter that suggest using alternative string/[]byte functions

Author: butuzov

go.mod

@@ -24,6 +24,7 @@ require (
 	github.com/breml/bidichk v0.2.4
 	github.com/breml/errchkjson v0.3.1
 	github.com/butuzov/ireturn v0.2.0
+	github.com/butuzov/mirror v0.1.0
 	github.com/charithe/durationcheck v0.0.10
 	github.com/curioswitch/go-reassign v0.2.0
 	github.com/daixiang0/gci v0.10.1

go.sum

@@ -0,0 +1,31 @@
+package golinters
+
+import (
+	"github.com/butuzov/mirror"
+	"golang.org/x/tools/go/analysis"
+
+	"github.com/golangci/golangci-lint/pkg/golinters/goanalysis"
+)
+
+func NewMirror() *goanalysis.Linter {
+	a := mirror.NewAnalyzer()
+
+	// mirror only lints test files if the `--with-tests` flag is passed, so we
+	// pass the `with-tests` flag as true to the analyzer before running it. This
+	// can be turned off by using the regular golangci-lint flags such as `--tests`
+	// or `--skip-files` or can be disabled per linter via exclude rules (see
+	// https://github.com/golangci/golangci-lint/issues/2527#issuecomment-1023707262)
+
+	cfg := map[string]map[string]any{
+		a.Name: {
+			"with-tests": true,
+		},
+	}
+
+	return goanalysis.NewLinter(
+		a.Name,
+		a.Doc,
+		[]*analysis.Analyzer{a},
+		cfg,
+	).WithLoadMode(goanalysis.LoadModeWholeProgram)
+}

pkg/golinters/mirror.go

@@ -650,6 +650,12 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 			WithURL("https://github.com/mdempsky/maligned").
 			Deprecated("The repository of the linter has been archived by the owner.", "v1.38.0", "govet 'fieldalignment'"),
 
+		linter.NewConfig(golinters.NewMirror()).
+			WithSince("v1.53.0").
+			WithPresets(linter.PresetStyle).
+			WithLoadForGoAnalysis().
+			WithURL("https://github.com/butuzov/mirror"),
+
 		linter.NewConfig(golinters.NewMisspell(misspellCfg)).
 			WithSince("v1.8.0").
 			WithPresets(linter.PresetStyle, linter.PresetComment).

pkg/lint/lintersdb/manager.go

@@ -0,0 +1,12 @@
+//golangcitest:args -Emirror
+package testdata
+
+import (
+	"strings"
+	"unicode/utf8"
+)
+
+func foobar() {
+	_ = utf8.RuneCount([]byte("foobar"))                                                                            // want `avoid allocations with utf8\.RuneCountInString`
+	_ = strings.Compare(string([]byte{'f', 'o', 'o', 'b', 'a', 'r'}), string([]byte{'f', 'o', 'o', 'b', 'a', 'r'})) // want `avoid allocations with bytes\.Compare`
+}