fix(local): prune empty parent dirs after blob delete (#3290)

Deleting a folder removed file blobs but left the empty directory
skeleton on the local filesystem. After a successful remove, walk
upward deleting empty ancestors — os.Remove self-terminates on the
first non-empty dir, and the climb is bounded to the application root.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

pkg/filemanager/driver/local/local.go

@@ -7,6 +7,7 @@ import (
 	"io"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 
 	"github.com/cloudreve/Cloudreve/v4/ent"
@@ -184,6 +185,8 @@ func (handler *Driver) Delete(ctx context.Context, files ...string) ([]string, e
 				handler.l.Warning("Failed to delete file: %s", err)
 				retErr = err
 				deleteFailed = append(deleteFailed, value)
+			} else {
+				handler.pruneEmptyAncestors(filePath)
 			}
 		}
 
@@ -194,6 +197,23 @@ func (handler *Driver) Delete(ctx context.Context, files ...string) ([]string, e
 	return deleteFailed, retErr
 }
 
+// pruneEmptyAncestors removes empty parent directories left behind by a
+// deleted blob (#3290). os.Remove fails on non-empty directories, so the
+// walk self-terminates; the climb is also bounded to the application
+// root so it can never escape the storage tree.
+func (handler *Driver) pruneEmptyAncestors(filePath string) {
+	root := filepath.Dir(util.RelativePath("x"))
+	for dir := filepath.Dir(filePath); ; dir = filepath.Dir(dir) {
+		rel, err := filepath.Rel(root, dir)
+		if err != nil || rel == "." || strings.HasPrefix(rel, "..") {
+			return
+		}
+		if err := os.Remove(dir); err != nil {
+			return
+		}
+	}
+}
+
 // Thumb 获取文件缩略图
 func (handler *Driver) Thumb(ctx context.Context, expire *time.Time, ext string, e fs.Entity) (string, error) {
 	return "", errors.New("not implemented")

pkg/filemanager/driver/local/local_test.go

@@ -0,0 +1,39 @@
+package local
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/cloudreve/Cloudreve/v4/pkg/logging"
+	"github.com/cloudreve/Cloudreve/v4/pkg/util"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDeletePrunesEmptyAncestors(t *testing.T) {
+	old := util.UseWorkingDir
+	util.UseWorkingDir = true
+	t.Cleanup(func() { util.UseWorkingDir = old })
+	t.Chdir(t.TempDir())
+
+	nested := filepath.Join("uploads", "3", "deep", "nested")
+	require.NoError(t, os.MkdirAll(nested, 0755))
+	require.NoError(t, os.WriteFile(filepath.Join(nested, "a.txt"), []byte("a"), 0644))
+	require.NoError(t, os.WriteFile(filepath.Join(nested, "b.txt"), []byte("b"), 0644))
+	require.NoError(t, os.WriteFile(filepath.Join("uploads", "keep.txt"), []byte("k"), 0644))
+
+	d := New(nil, logging.NewConsoleLogger(logging.LevelDebug), nil)
+
+	// Deleting both files should remove deep/nested/3 but stop at uploads
+	// (still holds keep.txt).
+	failed, err := d.Delete(context.Background(),
+		filepath.Join("uploads", "3", "deep", "nested", "a.txt"),
+		filepath.Join("uploads", "3", "deep", "nested", "b.txt"),
+	)
+	require.NoError(t, err)
+	require.Empty(t, failed)
+	require.NoDirExists(t, filepath.Join("uploads", "3"))
+	require.DirExists(t, "uploads")
+	require.FileExists(t, filepath.Join("uploads", "keep.txt"))
+}