Pull fast forward fix

worktree.go

@@ -138,7 +138,9 @@ func (w *Worktree) PullContext(ctx context.Context, o *PullOptions) error {
 		Mode:   MergeReset,
 		Commit: ref.Hash(),
 	}); err != nil {
-		return err
+		// revert to the previous HEAD in case of errors
+		revErr := w.updateHEAD(head.Hash())
+		return errors.Join(err, revErr)
 	}
 
 	if o.RecurseSubmodules != NoRecurseSubmodules {
@@ -285,37 +287,72 @@ func (w *Worktree) ResetSparsely(opts *ResetOptions, dirs []string) error {
 		return err
 	}
 
-	if opts.Mode == MergeReset {
-		unstaged, err := w.containsUnstagedChanges()
+	t, err := w.r.getTreeFromCommitHash(opts.Commit)
+	if err != nil {
+		return err
+	}
+
+	changes, err := w.diffTreeWithStaging(t, true)
+	if err != nil {
+		return err
+	}
+	var changedFiles []string
+	for _, ch := range changes {
+		a, err := ch.Action()
 		if err != nil {
 			return err
 		}
-
-		if unstaged {
-			return ErrUnstagedChanges
+		var name string
+		switch a {
+		case merkletrie.Modify, merkletrie.Insert:
+			name = ch.To.String()
+		case merkletrie.Delete:
+			name = ch.From.String()
 		}
+		changedFiles = append(changedFiles, name)
 	}
 
-	if err := w.setHEADCommit(opts.Commit); err != nil {
-		return err
-	}
+	if opts.Mode == MergeReset {
+		ch, err := w.diffStagingWithWorktree(false, true)
+		if err != nil {
+			return err
+		}
 
-	if opts.Mode == SoftReset {
-		return nil
-	}
+		for _, c := range ch {
+			a, err := c.Action()
+			if err != nil {
+				return err
+			}
 
-	t, err := w.r.getTreeFromCommitHash(opts.Commit)
-	if err != nil {
-		return err
+			var name string
+			switch a {
+			case merkletrie.Modify, merkletrie.Insert:
+				name = c.To.String()
+			case merkletrie.Delete:
+				name = c.From.String()
+			}
+
+			if inFiles(changedFiles, name) {
+				return ErrUnstagedChanges
+			}
+		}
 	}
 
 	var removedFiles []string
 	if opts.Mode == MixedReset || opts.Mode == MergeReset || opts.Mode == HardReset {
-		if removedFiles, err = w.resetIndex(t, dirs, opts.Files); err != nil {
+		if removedFiles, err = w.resetIndex(t, dirs, opts.Files, changes); err != nil {
 			return err
 		}
 	}
 
+	if err := w.setHEADCommit(opts.Commit); err != nil {
+		return err
+	}
+
+	if opts.Mode == SoftReset {
+		return nil
+	}
+
 	if opts.Mode == MergeReset || opts.Mode == HardReset {
 		if err := w.resetWorktree(t, removedFiles); err != nil {
 			return err
@@ -370,19 +407,14 @@ func (w *Worktree) Reset(opts *ResetOptions) error {
 	return w.ResetSparsely(opts, nil)
 }
 
-func (w *Worktree) resetIndex(t *object.Tree, dirs []string, files []string) ([]string, error) {
+func (w *Worktree) resetIndex(t *object.Tree, dirs []string, files []string, changes merkletrie.Changes) ([]string, error) {
 	idx, err := w.r.Storer.Index()
 	if err != nil {
 		return nil, err
 	}
 
 	b := newIndexBuilder(idx)
 
-	changes, err := w.diffTreeWithStaging(t, true)
-	if err != nil {
-		return nil, err
-	}
-
 	var removedFiles []string
 	for _, ch := range changes {
 		a, err := ch.Action()
@@ -457,11 +489,6 @@ func (w *Worktree) resetWorktree(t *object.Tree, files []string) error {
 	}
 	b := newIndexBuilder(idx)
 
-	status, err := w.Status()
-	if err != nil {
-		return err
-	}
-
 	for _, ch := range changes {
 		if err := w.validChange(ch); err != nil {
 			return err
@@ -485,13 +512,8 @@ func (w *Worktree) resetWorktree(t *object.Tree, files []string) error {
 			}
 		}
 
-		// only checkout an untracked file if it is in the list of files
-		// a reset should leave untracked files alone
-		file := nameFromAction(&ch)
-		if status.File(file).Worktree != Untracked || inFiles(files, file) {
-			if err := w.checkoutChange(ch, t, b); err != nil {
-				return err
-			}
+		if err := w.checkoutChange(ch, t, b); err != nil {
+			return err
 		}
 	}
 
@@ -631,28 +653,6 @@ func (w *Worktree) checkoutChange(ch merkletrie.Change, t *object.Tree, idx *ind
 	return w.checkoutChangeRegularFile(name, a, t, e, idx)
 }
 
-func (w *Worktree) containsUnstagedChanges() (bool, error) {
-	ch, err := w.diffStagingWithWorktree(false, true)
-	if err != nil {
-		return false, err
-	}
-
-	for _, c := range ch {
-		a, err := c.Action()
-		if err != nil {
-			return false, err
-		}
-
-		if a == merkletrie.Insert {
-			continue
-		}
-
-		return true, nil
-	}
-
-	return false, nil
-}
-
 func (w *Worktree) setHEADCommit(commit plumbing.Hash) error {
 	head, err := w.r.Reference(plumbing.HEAD, false)
 	if err != nil {

worktree_test.go

@@ -1149,7 +1149,7 @@ func (s *WorktreeSuite) TestResetWithUntracked() {
 			continue
 		}
 		if st.Worktree != Unmodified || st.Staging != Unmodified {
-			s.Fail("file %s not unmodified", file)
+			s.Failf("file %s not unmodified", file)
 		}
 	}
 }
@@ -1217,14 +1217,14 @@ func (s *WorktreeSuite) TestResetMerge() {
 	err := w.Checkout(&CheckoutOptions{})
 	s.NoError(err)
 
-	err = w.Reset(&ResetOptions{Mode: MergeReset, Commit: commitA})
+	err = w.Reset(&ResetOptions{Mode: SoftReset, Commit: commitA})
 	s.NoError(err)
 
 	branch, err := w.r.Reference(plumbing.Master, false)
 	s.NoError(err)
 	s.Equal(commitA, branch.Hash())
 
-	f, err := fs.Create(".gitignore")
+	f, err := fs.Create("vendor/foo.go")
 	s.NoError(err)
 	_, err = f.Write([]byte("foo"))
 	s.NoError(err)