feat: --exclude flag

Signed-off-by: Ilya Lesikov <ilya@lesikov.com>

Author: ilya-lesikov

internal/cli/root.go

@@ -11,11 +11,13 @@ import (
 
 func init() {
 	rootCmd.Flags().BoolVarP(&checkOnly, "check", "c", false, "Check if files need formatting (exit 1 if changes needed)")
+	rootCmd.Flags().StringArrayVarP(&excludePatterns, "exclude", "e", nil, "Exclude files matching glob pattern (can be specified multiple times)")
 }
 
 var (
-	checkOnly bool
-	rootCmd   = &cobra.Command{
+	checkOnly       bool
+	excludePatterns []string
+	rootCmd         = &cobra.Command{
 		Use:     "wormatter <path>...",
 		Short:   "A highly opinionated Go source code formatter",
 		Long:    "Wormatter is a DST-based Go source code formatter. Highly opinionated, but very comprehensive. Gofumpt built-in.",
@@ -33,7 +35,10 @@ func Execute() {
 }
 
 func run(_ *cobra.Command, args []string) error {
-	opts := formatter.Options{CheckOnly: checkOnly}
+	opts := formatter.Options{
+		CheckOnly:       checkOnly,
+		ExcludePatterns: excludePatterns,
+	}
 
 	for _, path := range args {
 		info, err := os.Stat(path)

pkg/formatter/file.go

@@ -18,7 +18,8 @@ import (
 var ErrNeedsFormatting = errors.New("file needs formatting")
 
 type Options struct {
-	CheckOnly bool
+	CheckOnly       bool
+	ExcludePatterns []string
 }
 
 func FormatDirectory(dir string, opts Options) error {
@@ -27,6 +28,9 @@ func FormatDirectory(dir string, opts Options) error {
 			return err
 		}
 		if !d.IsDir() && strings.HasSuffix(path, ".go") {
+			if matchesAnyPattern(path, opts.ExcludePatterns) {
+				return nil
+			}
 			if err := FormatFile(path, opts); err != nil {
 				return err
 			}
@@ -37,6 +41,10 @@ func FormatDirectory(dir string, opts Options) error {
 }
 
 func FormatFile(filePath string, opts Options) error {
+	if matchesAnyPattern(filePath, opts.ExcludePatterns) {
+		return nil
+	}
+
 	fset := token.NewFileSet()
 	f, err := decorator.ParseFile(fset, filePath, nil, parser.ParseComments)
 	if err != nil {
@@ -87,3 +95,16 @@ func FormatFile(filePath string, opts Options) error {
 
 	return os.WriteFile(filePath, formatted, 0o644)
 }
+
+func matchesAnyPattern(path string, patterns []string) bool {
+	for _, pattern := range patterns {
+		if matched, _ := filepath.Match(pattern, path); matched {
+			return true
+		}
+		if matched, _ := filepath.Match(pattern, filepath.Base(path)); matched {
+			return true
+		}
+	}
+
+	return false
+}