1 files changed, 23 insertions, 7 deletions
diff --git a/src/cmd/fix/main.go b/src/cmd/fix/main.go
index e72c66398f..d055929aac 100644
--- a/src/cmd/fix/main.go
+++ b/src/cmd/fix/main.go
@@ -13,7 +13,8 @@ import (
 	"go/parser"
 	"go/scanner"
 	"go/token"
-	"io/ioutil"
+	"io"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"sort"
@@ -127,7 +128,7 @@ func processFile(filename string, useStdin bool) error {
 		defer f.Close()
 	}
 
-	src, err := ioutil.ReadAll(f)
+	src, err := io.ReadAll(f)
 	if err != nil {
 		return err
 	}
@@ -137,6 +138,21 @@ func processFile(filename string, useStdin bool) error {
 		return err
 	}
 
+	// Make sure file is in canonical format.
+	// This "fmt" pseudo-fix cannot be disabled.
+	newSrc, err := gofmtFile(file)
+	if err != nil {
+		return err
+	}
+	if !bytes.Equal(newSrc, src) {
+		newFile, err := parser.ParseFile(fset, filename, newSrc, parserMode)
+		if err != nil {
+			return err
+		}
+		file = newFile
+		fmt.Fprintf(&fixlog, " fmt")
+	}
+
 	// Apply all fixes to file.
 	newFile := file
 	fixed := false
@@ -180,7 +196,7 @@ func processFile(filename string, useStdin bool) error {
 	// output of the printer run on a standard AST generated by the parser,
 	// but the source we generated inside the loop above is the
 	// output of the printer run on a mangled AST generated by a fixer.
-	newSrc, err := gofmtFile(newFile)
+	newSrc, err = gofmtFile(newFile)
 	if err != nil {
 		return err
 	}
@@ -200,7 +216,7 @@ func processFile(filename string, useStdin bool) error {
 		return nil
 	}
 
-	return ioutil.WriteFile(f.Name(), newSrc, 0)
+	return os.WriteFile(f.Name(), newSrc, 0)
 }
 
 func gofmt(n interface{}) string {
@@ -217,10 +233,10 @@ func report(err error) {
 }
 
 func walkDir(path string) {
-	filepath.Walk(path, visitFile)
+	filepath.WalkDir(path, visitFile)
 }
 
-func visitFile(path string, f os.FileInfo, err error) error {
+func visitFile(path string, f fs.DirEntry, err error) error {
 	if err == nil && isGoFile(f) {
 		err = processFile(path, false)
 	}
@@ -230,7 +246,7 @@ func visitFile(path string, f os.FileInfo, err error) error {
 	return nil
 }
 
-func isGoFile(f os.FileInfo) bool {
+func isGoFile(f fs.DirEntry) bool {
 	// ignore non-Go files
 	name := f.Name()
 	return !f.IsDir() && !strings.HasPrefix(name, ".") && strings.HasSuffix(name, ".go")