Merge pull request #4620 from MichaelEischer/improve-irregular-file-handling

Improve irregular file handling

changelog/unreleased/issue-4560

@@ -0,0 +1,14 @@
+Bugfix: Improve errors for irregular files on Windows
+
+Since Go 1.21, most filesystem reparse points on Windows are considered to be
+irregular files. This caused restic to show an `error: invalid node type ""`
+error message for those files.
+
+We have improved the error message to include the file path for those files:
+`error: nodeFromFileInfo path/to/file: unsupported file type "irregular"`.
+As irregular files are not required to behave like regular files, it is not
+possible to provide a generic way to back up those files.
+
+https://github.com/restic/restic/issues/4560
+https://github.com/restic/restic/pull/4620
+https://forum.restic.net/t/windows-backup-error-invalid-node-type/6875

internal/archiver/archiver.go

@@ -2,10 +2,12 @@ package archiver
 
 import (
 	"context"
+	"fmt"
 	"os"
 	"path"
 	"runtime"
 	"sort"
+	"strings"
 	"time"
 
 	"github.com/restic/restic/internal/debug"
@@ -168,6 +170,11 @@ func (arch *Archiver) error(item string, err error) error {
 		return err
 	}
 
+	// not all errors include the filepath, thus add it if it is missing
+	if !strings.Contains(err.Error(), item) {
+		err = fmt.Errorf("%v: %w", item, err)
+	}
+
 	errf := arch.Error(item, err)
 	if err != errf {
 		debug.Log("item %v: error was filtered by handler, before: %q, after: %v", item, err, errf)
@@ -183,7 +190,10 @@ func (arch *Archiver) nodeFromFileInfo(snPath, filename string, fi os.FileInfo)
 	}
 	// overwrite name to match that within the snapshot
 	node.Name = path.Base(snPath)
-	return node, errors.WithStack(err)
+	if err != nil {
+		return node, fmt.Errorf("nodeFromFileInfo %v: %w", filename, err)
+	}
+	return node, err
 }
 
 // loadSubtree tries to load the subtree referenced by node. In case of an error, nil is returned.

internal/restic/node.go

@@ -109,7 +109,7 @@ func NodeFromFileInfo(path string, fi os.FileInfo) (*Node, error) {
 }
 
 func nodeTypeFromFileInfo(fi os.FileInfo) string {
-	switch fi.Mode() & (os.ModeType | os.ModeCharDevice) {
+	switch fi.Mode() & os.ModeType {
 	case 0:
 		return "file"
 	case os.ModeDir:
@@ -124,6 +124,8 @@ func nodeTypeFromFileInfo(fi os.FileInfo) string {
 		return "fifo"
 	case os.ModeSocket:
 		return "socket"
+	case os.ModeIrregular:
+		return "irregular"
 	}
 
 	return ""
@@ -622,7 +624,7 @@ func (node *Node) fillExtra(path string, fi os.FileInfo) error {
 	case "fifo":
 	case "socket":
 	default:
-		return errors.Errorf("invalid node type %q", node.Type)
+		return errors.Errorf("unsupported file type %q", node.Type)
 	}
 
 	return node.fillExtendedAttributes(path)