Merge pull request #966 from aymanbagabas/taghash-checkout

git: worktree checkout tag hash id (#959)

options.go

@@ -324,9 +324,9 @@ var (
 
 // CheckoutOptions describes how a checkout operation should be performed.
 type CheckoutOptions struct {
-	// Hash is the hash of the commit to be checked out. If used, HEAD will be
-	// in detached mode. If Create is not used, Branch and Hash are mutually
-	// exclusive.
+	// Hash is the hash of a commit or tag to be checked out. If used, HEAD
+	// will be in detached mode. If Create is not used, Branch and Hash are
+	// mutually exclusive.
 	Hash plumbing.Hash
 	// Branch to be checked out, if Branch and Hash are empty is set to `master`.
 	Branch plumbing.ReferenceName

worktree.go

@@ -227,36 +227,33 @@ func (w *Worktree) createBranch(opts *CheckoutOptions) error {
 }
 
 func (w *Worktree) getCommitFromCheckoutOptions(opts *CheckoutOptions) (plumbing.Hash, error) {
-	if !opts.Hash.IsZero() {
-		return opts.Hash, nil
-	}
-
-	b, err := w.r.Reference(opts.Branch, true)
-	if err != nil {
-		return plumbing.ZeroHash, err
-	}
+	hash := opts.Hash
+	if hash.IsZero() {
+		b, err := w.r.Reference(opts.Branch, true)
+		if err != nil {
+			return plumbing.ZeroHash, err
+		}
 
-	if !b.Name().IsTag() {
-		return b.Hash(), nil
+		hash = b.Hash()
 	}
 
-	o, err := w.r.Object(plumbing.AnyObject, b.Hash())
+	o, err := w.r.Object(plumbing.AnyObject, hash)
 	if err != nil {
 		return plumbing.ZeroHash, err
 	}
 
 	switch o := o.(type) {
 	case *object.Tag:
 		if o.TargetType != plumbing.CommitObject {
-			return plumbing.ZeroHash, fmt.Errorf("unsupported tag object target %q", o.TargetType)
+			return plumbing.ZeroHash, fmt.Errorf("%w: tag target %q", object.ErrUnsupportedObject, o.TargetType)
 		}
 
 		return o.Target, nil
 	case *object.Commit:
 		return o.Hash, nil
 	}
 
-	return plumbing.ZeroHash, fmt.Errorf("unsupported tag target %q", o.Type())
+	return plumbing.ZeroHash, fmt.Errorf("%w: %q", object.ErrUnsupportedObject, o.Type())
 }
 
 func (w *Worktree) setHEADToCommit(commit plumbing.Hash) error {

worktree_commit.go

@@ -263,4 +263,4 @@ func (h *buildTreeHelper) copyTreeToStorageRecursive(parent string, t *object.Tr
 		return hash, nil
 	}
 	return h.s.SetEncodedObject(o)
-}
+}

worktree_test.go

@@ -886,6 +886,41 @@ func (s *WorktreeSuite) TestCheckoutTag(c *C) {
 	c.Assert(head.Name().String(), Equals, "HEAD")
 }
 
+func (s *WorktreeSuite) TestCheckoutTagHash(c *C) {
+	f := fixtures.ByTag("tags").One()
+	r := s.NewRepositoryWithEmptyWorktree(f)
+	w, err := r.Worktree()
+	c.Assert(err, IsNil)
+
+	for _, hash := range []string{
+		"b742a2a9fa0afcfa9a6fad080980fbc26b007c69", // annotated tag
+		"ad7897c0fb8e7d9a9ba41fa66072cf06095a6cfc", // commit tag
+		"f7b877701fbf855b44c0a9e86f3fdce2c298b07f", // lightweight tag
+	} {
+		err = w.Checkout(&CheckoutOptions{
+			Hash: plumbing.NewHash(hash),
+		})
+		c.Assert(err, IsNil)
+		head, err := w.r.Head()
+		c.Assert(err, IsNil)
+		c.Assert(head.Name().String(), Equals, "HEAD")
+
+		status, err := w.Status()
+		c.Assert(err, IsNil)
+		c.Assert(status.IsClean(), Equals, true)
+	}
+
+	for _, hash := range []string{
+		"fe6cb94756faa81e5ed9240f9191b833db5f40ae", // blob tag
+		"152175bf7e5580299fa1f0ba41ef6474cc043b70", // tree tag
+	} {
+		err = w.Checkout(&CheckoutOptions{
+			Hash: plumbing.NewHash(hash),
+		})
+		c.Assert(err, NotNil)
+	}
+}
+
 func (s *WorktreeSuite) TestCheckoutBisect(c *C) {
 	if testing.Short() {
 		c.Skip("skipping test in short mode.")