[linter-miner] feat(linters): add ioutildeprecated linter to flag deprecated io/ioutil usage

cmd/linters/main.go

@@ -34,6 +34,7 @@ import (
 	"github.com/github/gh-aw/pkg/linters/httpnoctx"
 	"github.com/github/gh-aw/pkg/linters/httprespbodyclose"
 	"github.com/github/gh-aw/pkg/linters/httpstatuscode"
+	"github.com/github/gh-aw/pkg/linters/ioutildeprecated"
 	"github.com/github/gh-aw/pkg/linters/jsonmarshalignoredeerror"
 	"github.com/github/gh-aw/pkg/linters/largefunc"
 	"github.com/github/gh-aw/pkg/linters/lenstringsplit"
@@ -82,6 +83,7 @@ func main() {
 		hardcodedfilepath.Analyzer,
 		httpnoctx.Analyzer,
 		httprespbodyclose.Analyzer,
+		ioutildeprecated.Analyzer,
 		httpstatuscode.Analyzer,
 		largefunc.Analyzer,
 		manualmutexunlock.Analyzer,

pkg/linters/ioutildeprecated/ioutildeprecated.go

@@ -0,0 +1,83 @@
+// Package ioutildeprecated implements a Go analysis linter that flags calls to
+// functions from the deprecated io/ioutil package and suggests their replacements
+// in the io and os packages (deprecated since Go 1.16).
+package ioutildeprecated
+
+import (
+	"go/ast"
+	"go/types"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+
+	"github.com/github/gh-aw/pkg/linters/internal/astutil"
+	"github.com/github/gh-aw/pkg/linters/internal/filecheck"
+	"github.com/github/gh-aw/pkg/linters/internal/nolint"
+)
+
+// replacements maps deprecated ioutil function names to their modern equivalents.
+var replacements = map[string]string{
+	"ReadAll":   "io.ReadAll",
+	"ReadFile":  "os.ReadFile",
+	"WriteFile": "os.WriteFile",
+	"TempFile":  "os.CreateTemp",
+	"TempDir":   "os.MkdirTemp",
+	"ReadDir":   "os.ReadDir",
+	"NopCloser": "io.NopCloser",
+	"Discard":   "io.Discard",
+}
+
+// Analyzer is the ioutil-deprecated analysis pass.
+var Analyzer = &analysis.Analyzer{
+	Name:     "ioutildeprecated",
+	Doc:      "reports uses of deprecated io/ioutil functions that should be replaced with io or os package equivalents",
+	URL:      "https://github.com/github/gh-aw/tree/main/pkg/linters/ioutildeprecated",
+	Requires: []*analysis.Analyzer{inspect.Analyzer},
+	Run:      run,
+}
+
+func run(pass *analysis.Pass) (any, error) {
+	root, err := astutil.Root(pass)
+	if err != nil {
+		return nil, err
+	}
+	noLintLinesByFile := nolint.BuildLineIndex(pass, "ioutildeprecated")
+
+	for cur := range root.Preorder((*ast.SelectorExpr)(nil)) {
+		sel, ok := cur.Node().(*ast.SelectorExpr)
+		if !ok {
+			continue
+		}
+
+		pos := pass.Fset.PositionFor(sel.Pos(), false)
+		if filecheck.IsTestFile(pos.Filename) {
+			continue
+		}
+		if nolint.HasDirective(pos, noLintLinesByFile) {
+			continue
+		}
+
+		pkgIdent, ok := sel.X.(*ast.Ident)
+		if !ok {
+			continue
+		}
+		if pass.TypesInfo == nil {
+			continue
+		}
+		obj := pass.TypesInfo.ObjectOf(pkgIdent)
+		if obj == nil {
+			continue
+		}
+		pkgName, ok := obj.(*types.PkgName)
+		if !ok || pkgName.Imported().Path() != "io/ioutil" {
+			continue
+		}
+
+		funcName := sel.Sel.Name
+		if replacement, found := replacements[funcName]; found {
+			pass.ReportRangef(sel, "ioutil.%s is deprecated; use %s instead", funcName, replacement)
+		}
+	}
+
+	return nil, nil
+}

pkg/linters/ioutildeprecated/ioutildeprecated_test.go

@@ -0,0 +1,16 @@
+//go:build !integration
+
+package ioutildeprecated_test
+
+import (
+	"testing"
+
+	"golang.org/x/tools/go/analysis/analysistest"
+
+	"github.com/github/gh-aw/pkg/linters/ioutildeprecated"
+)
+
+func TestIoutilDeprecated(t *testing.T) {
+	testdata := analysistest.TestData()
+	analysistest.Run(t, testdata, ioutildeprecated.Analyzer, "ioutildeprecated")
+}

pkg/linters/ioutildeprecated/testdata/src/ioutildeprecated/ioutildeprecated.go

@@ -0,0 +1,39 @@
+package ioutildeprecated
+
+import (
+	"io/ioutil"
+	"os"
+)
+
+func BadReadAll() {
+	f, _ := os.Open("file.txt")
+	defer f.Close()
+	_, _ = ioutil.ReadAll(f) // want `ioutil\.ReadAll is deprecated`
+}
+
+func BadReadFile() {
+	_, _ = ioutil.ReadFile("file.txt") // want `ioutil\.ReadFile is deprecated`
+}
+
+func BadWriteFile() {
+	_ = ioutil.WriteFile("file.txt", []byte("hello"), 0644) // want `ioutil\.WriteFile is deprecated`
+}
+
+func BadTempFile() {
+	_, _ = ioutil.TempFile("", "prefix") // want `ioutil\.TempFile is deprecated`
+}
+
+func BadTempDir() {
+	_, _ = ioutil.TempDir("", "prefix") // want `ioutil\.TempDir is deprecated`
+}
+
+func BadReadDir() {
+	_, _ = ioutil.ReadDir(".") // want `ioutil\.ReadDir is deprecated`
+}
+
+func GoodReadAll() {
+	f, _ := os.Open("file.txt")
+	defer f.Close()
+	// Using io.ReadAll is fine
+	_ = f
+}