fix: remove temp file rename

Signed-off-by: mrjoelkamp <joel.kamp@docker.com>

metadata/updater/updater.go

@@ -579,38 +579,6 @@ func (update *Updater) preOrderDepthFirstWalk(targetFilePath string) (*metadata.
 	return nil, fmt.Errorf("target %s not found", targetFilePath)
 }
 
-func moveFile(source, destination string) (err error) {
-	// can only safely rename on any OS if source and destination are in the same directory
-	if filepath.Dir(source) == filepath.Dir(destination) {
-		return os.Rename(source, destination)
-	}
-
-	inputFile, err := os.Open(source)
-	if err != nil {
-		return fmt.Errorf("couldn't open source file: %s", err)
-	}
-	defer inputFile.Close()
-	outputFile, err := os.Create(destination)
-	if err != nil {
-		return fmt.Errorf("couldn't open dest file: %s", err)
-	}
-	defer outputFile.Close()
-	c, err := io.Copy(outputFile, inputFile)
-	if err != nil {
-		return fmt.Errorf("writing to output file failed: %s", err)
-	}
-	if c <= 0 {
-		return fmt.Errorf("nothing copied to output file")
-	}
-	inputFile.Close()
-	// The copy was successful, so now delete the original file
-	err = os.Remove(source)
-	if err != nil {
-		return fmt.Errorf("failed removing original file: %s", err)
-	}
-	return nil
-}
-
 // persistMetadata writes metadata to disk atomically to avoid data loss
 func (update *Updater) persistMetadata(roleName string, data []byte) error {
 	log := metadata.GetLogger()
@@ -620,34 +588,16 @@ func (update *Updater) persistMetadata(roleName string, data []byte) error {
 	}
 	// caching enabled, proceed with persisting the metadata locally
 	fileName := filepath.Join(update.cfg.LocalMetadataDir, fmt.Sprintf("%s.json", url.QueryEscape(roleName)))
-	cwd, err := os.Getwd()
-	if err != nil {
-		return err
-	}
-	// create a temporary file
-	file, err := os.CreateTemp(cwd, "tuf_tmp")
-	if err != nil {
-		return err
-	}
-	defer file.Close()
 	// write the data content to the temporary file
-	err = os.WriteFile(file.Name(), data, 0644)
+	err := os.WriteFile(fileName, data, 0644)
 	if err != nil {
-		// delete the temporary file if there was an error while writing
-		errRemove := os.Remove(file.Name())
+		// delete the file if there was an error while writing
+		errRemove := os.Remove(fileName)
 		if errRemove != nil {
-			log.Info("Failed to delete temporary file", "name", file.Name())
+			log.Info("Failed to delete file", "name", fileName)
 		}
 		return err
 	}
-
-	// can't move/rename an open file on windows, so close it first
-	file.Close()
-	// if all okay, rename the temporary file to the desired one
-	err = moveFile(file.Name(), fileName)
-	if err != nil {
-		return err
-	}
 	read, err := os.ReadFile(fileName)
 	if err != nil {
 		return err