Worktree, check for empty parent dirs during Reset (Fixes #670)

worktree.go

@@ -410,7 +410,7 @@ func (w *Worktree) checkoutChange(ch merkletrie.Change, t *object.Tree, idx *ind
 
 		isSubmodule = e.Mode == filemode.Submodule
 	case merkletrie.Delete:
-		return rmFileAndDirIfEmpty(w.Filesystem, ch.From.String())
+		return rmFileAndDirsIfEmpty(w.Filesystem, ch.From.String())
 	}
 
 	if isSubmodule {
@@ -778,8 +778,10 @@ func (w *Worktree) doClean(status Status, opts *CleanOptions, dir string, files
 	}
 
 	if opts.Dir && dir != "" {
-		return doCleanDirectories(w.Filesystem, dir)
+		_, err := removeDirIfEmpty(w.Filesystem, dir)
+		return err
 	}
+
 	return nil
 }
 
@@ -920,25 +922,52 @@ func findMatchInFile(file *object.File, treeName string, opts *GrepOptions) ([]G
 	return grepResults, nil
 }
 
-func rmFileAndDirIfEmpty(fs billy.Filesystem, name string) error {
+// will walk up the directory tree removing all encountered empty
+// directories, not just the one containing this file
+func rmFileAndDirsIfEmpty(fs billy.Filesystem, name string) error {
 	if err := util.RemoveAll(fs, name); err != nil {
 		return err
 	}
 
 	dir := filepath.Dir(name)
-	return doCleanDirectories(fs, dir)
+	for {
+		removed, err := removeDirIfEmpty(fs, dir)
+		if err != nil {
+			return err
+		}
+
+		if !removed {
+			// directory was not empty and not removed,
+			// stop checking parents
+			break
+		}
+
+		// move to parent directory
+		dir = filepath.Dir(dir)
+	}
+
+	return nil
 }
 
-// doCleanDirectories removes empty subdirs (without files)
-func doCleanDirectories(fs billy.Filesystem, dir string) error {
+// removeDirIfEmpty will remove the supplied directory `dir` if
+// `dir` is empty
+// returns true if the directory was removed
+func removeDirIfEmpty(fs billy.Filesystem, dir string) (bool, error) {
 	files, err := fs.ReadDir(dir)
 	if err != nil {
-		return err
+		return false, err
 	}
-	if len(files) == 0 {
-		return fs.Remove(dir)
+
+	if len(files) > 0 {
+		return false, nil
 	}
-	return nil
+
+	err = fs.Remove(dir)
+	if err != nil {
+		return false, err
+	}
+
+	return true, nil
 }
 
 type indexBuilder struct {

worktree_test.go

@@ -3,6 +3,7 @@ package git
 import (
 	"bytes"
 	"context"
+	"errors"
 	"io"
 	"io/ioutil"
 	"os"
@@ -2210,6 +2211,56 @@ func (s *WorktreeSuite) TestGrep(c *C) {
 	}
 }
 
+func (s *WorktreeSuite) TestResetLingeringDirectories(c *C) {
+	dir, clean := s.TemporalDir()
+	defer clean()
+
+	commitOpts := &CommitOptions{Author: &object.Signature{
+		Name:  "foo",
+		Email: "foo@foo.foo",
+		When:  time.Now(),
+	}}
+
+	repo, err := PlainInit(dir, false)
+	c.Assert(err, IsNil)
+
+	w, err := repo.Worktree()
+	c.Assert(err, IsNil)
+
+	os.WriteFile(filepath.Join(dir, "README"), []byte("placeholder"), 0o644)
+
+	_, err = w.Add(".")
+	c.Assert(err, IsNil)
+
+	initialHash, err := w.Commit("Initial commit", commitOpts)
+	c.Assert(err, IsNil)
+
+	os.MkdirAll(filepath.Join(dir, "a", "b"), 0o755)
+	os.WriteFile(filepath.Join(dir, "a", "b", "1"), []byte("1"), 0o644)
+
+	_, err = w.Add(".")
+	c.Assert(err, IsNil)
+
+	_, err = w.Commit("Add file in nested sub-directories", commitOpts)
+	c.Assert(err, IsNil)
+
+	// reset to initial commit, which should remove a/b/1, a/b, and a
+	err = w.Reset(&ResetOptions{
+		Commit: initialHash,
+		Mode:   HardReset,
+	})
+	c.Assert(err, IsNil)
+
+	_, err = os.Stat(filepath.Join(dir, "a", "b", "1"))
+	c.Assert(errors.Is(err, os.ErrNotExist), Equals, true)
+
+	_, err = os.Stat(filepath.Join(dir, "a", "b"))
+	c.Assert(errors.Is(err, os.ErrNotExist), Equals, true)
+
+	_, err = os.Stat(filepath.Join(dir, "a"))
+	c.Assert(errors.Is(err, os.ErrNotExist), Equals, true)
+}
+
 func (s *WorktreeSuite) TestAddAndCommit(c *C) {
 	expectedFiles := 2