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

…#3825)

.golangci.reference.yml

@@ -2140,6 +2140,7 @@ linters:
  - maintidx
  - makezero
  - maligned
+ - mirror
  - misspell
  - musttag
  - nakedret
@@ -2253,6 +2254,7 @@ linters:
  - maintidx
  - makezero
  - maligned
+ - mirror
  - misspell
  - musttag
  - nakedret

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 v1.1.0
  github.com/charithe/durationcheck v0.0.10
  github.com/curioswitch/go-reassign v0.2.0
  github.com/daixiang0/gci v0.10.1

pkg/golinters/mirror.go

@@ -0,0 +1,70 @@
+package golinters
+
+import (
+ "sync"
+
+ "github.com/butuzov/mirror"
+ "golang.org/x/tools/go/analysis"
+
+ "github.com/golangci/golangci-lint/pkg/golinters/goanalysis"
+ "github.com/golangci/golangci-lint/pkg/lint/linter"
+ "github.com/golangci/golangci-lint/pkg/result"
+)
+
+func NewMirror() *goanalysis.Linter {
+ var (
+ mu sync.Mutex
+ issues []goanalysis.Issue
+ )
+
+ a := mirror.NewAnalyzer()
+ a.Run = func(pass *analysis.Pass) (any, error) {
+ // 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:/golangci/golangci-lint/issues/2527#issuecomment-1023707262)
+ violations := mirror.Run(pass, true)
+
+ if len(violations) == 0 {
+ return nil, nil
+ }
+
+ for index := range violations {
+ i := violations[index].Issue(pass.Fset)
+
+ issue := result.Issue{
+ FromLinter: a.Name,
+ Text: i.Message,
+ Pos: i.Start,
+ }
+
+ if len(i.InlineFix) > 0 {
+ issue.Replacement = &result.Replacement{
+ Inline: &result.InlineFix{
+ StartCol: i.Start.Column - 1,
+ Length: len(i.Original),
+ NewString: i.InlineFix,
+ },
+ }
+ }
+
+ mu.Lock()
+ issues = append(issues, goanalysis.NewIssue(&issue, pass))
+ mu.Unlock()
+ }
+
+ return nil, nil
+ }
+
+ analyzer := goanalysis.NewLinter(
+ a.Name,
+ a.Doc,
+ []*analysis.Analyzer{a},
+ nil,
+ ).WithIssuesReporter(func(*linter.Context) []goanalysis.Issue {
+ return issues
+ }).WithLoadMode(goanalysis.LoadModeTypesInfo)
+
+ return analyzer
+}

pkg/lint/lintersdb/manager.go

@@ -654,6 +654,12 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
  WithURL("https:/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:/butuzov/mirror"),
+
  linter.NewConfig(golinters.NewMisspell(misspellCfg)).
  WithSince("v1.8.0").
  WithPresets(linter.PresetStyle, linter.PresetComment).

test/testdata/mirror.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`
+}