Handle symlinks, Staggered versioner (fixes #1071)

internal/versioner/staggered.go

@@ -45,16 +45,6 @@ type Staggered struct {
 	mutex         *sync.Mutex
 }
 
-// Check if file or dir
-func isFile(path string) bool {
-	fileInfo, err := os.Stat(path)
-	if err != nil {
-		l.Infoln("versioner isFile:", err)
-		return false
-	}
-	return fileInfo.Mode().IsRegular()
-}
-
 // Rename versions with old version format
 func (v Staggered) renameOld() {
 	err := filepath.Walk(v.versionsPath, func(path string, f os.FileInfo, err error) error {
@@ -167,14 +157,16 @@ func (v Staggered) clean() {
 		if err != nil {
 			return err
 		}
-		switch mode := f.Mode(); {
+
-		case mode.IsDir():
+		if f.Mode().IsDir() && f.Mode()&os.ModeSymlink == 0 {
 			filesPerDir[path] = 0
 			if path != v.versionsPath {
 				dir := filepath.Dir(path)
 				filesPerDir[dir]++
 			}
-		case mode.IsRegular():
+		} else {
+			// Regular file, or possibly a symlink.
+
 			extension := filenameTag(path)
 			dir := filepath.Dir(path)
 			name := path[:len(path)-len(extension)-1]
@@ -227,7 +219,17 @@ func (v Staggered) expire(versions []string) {
 	var prevAge int64
 	firstFile := true
 	for _, file := range versions {
-		if isFile(file) {
+		fi, err := os.Stat(file)
+		if err != nil {
+			l.Warnln("versioner:", err)
+			continue
+		}
+
+		if fi.IsDir() {
+			l.Infof("non-file %q is named like a file version", file)
+			continue
+		}
+
 		versionTime, err := time.Parse(TimeFormat, filenameTag(file))
 		if err != nil {
 			l.Infof("Versioner: file name %q is invalid: %v", file, err)
@@ -274,9 +276,6 @@ func (v Staggered) expire(versions []string) {
 		}
 
 		prevAge = age
-		} else {
-			l.Infof("non-file %q is named like a file version", file)
-		}
 	}
 }
 
@@ -289,7 +288,7 @@ func (v Staggered) Archive(filePath string) error {
 	v.mutex.Lock()
 	defer v.mutex.Unlock()
 
-	if _, err := os.Stat(filePath); err != nil {
+	if _, err := os.Lstat(filePath); err != nil {
 		if os.IsNotExist(err) {
 			if debug {
 				l.Debugln("not archiving nonexistent file", filePath)