5 files changed, 271 insertions, 10 deletions

diff --git a/git_superproject.py b/git_superproject.py
index 81a6b2e59..27bc10e10 100644
--- a/git_superproject.py
+++ b/git_superproject.py
@@ -34,6 +34,7 @@ import urllib.parse
 
 from git_command import git_require
 from git_command import GitCommand
+from git_config import IsId
 from git_config import RepoConfig
 from git_refs import GitRefs
 import platform_utils
@@ -132,6 +133,10 @@ class Superproject:
         """Set the _print_messages attribute."""
         self._print_messages = value
 
+    def SetRevisionId(self, revision_id: str) -> None:
+        """Set the revisionId of the superproject to sync to."""
+        self.revision = revision_id
+
     @property
     def commit_id(self):
         """Returns the commit ID of the superproject checkout."""
@@ -314,7 +319,14 @@ class Superproject:
             cmd.extend(["--negotiation-tip", rev_commit])
 
         if self.revision:
-            cmd += [self.revision + ":" + self.revision]
+            # If revision is a commit hash, fetch it directly to avoid
+            # creating a local branch of the same name.
+            refspec = (
+                self.revision
+                if IsId(self.revision)
+                else f"{self.revision}:{self.revision}"
+            )
+            cmd.append(refspec)
         p = GitCommand(
             None,
             cmd,
@@ -401,6 +413,8 @@ class Superproject:
 
         if not self._Init():
             return SyncResult(False, should_exit)
+        if IsId(self.revision) and self.commit_id:
+            return SyncResult(True, False)
         if not self._Fetch():
             return SyncResult(False, should_exit)
         if not self._quiet:
diff --git a/man/repo-smartsync.1 b/man/repo-smartsync.1
index 5ea063e6b..25b85f126 100644
--- a/man/repo-smartsync.1
+++ b/man/repo-smartsync.1
@@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man.
-.TH REPO "1" "August 2025" "repo smartsync" "Repo Manual"
+.TH REPO "1" "May 2026" "repo smartsync" "Repo Manual"
 .SH NAME
 repo \- repo smartsync - manual page for repo smartsync
 .SH SYNOPSIS
@@ -101,6 +101,10 @@ implies \fB\-c\fR
 \fB\-\-no\-use\-superproject\fR
 disable use of manifest superprojects
 .TP
+\fB\-\-superproject\-revision\fR=\fI\,SUPERPROJECT_REVISION\/\fR
+sync to superproject revision (applies to outer
+manifest)
+.TP
 \fB\-\-tags\fR
 fetch tags
 .TP
diff --git a/man/repo-sync.1 b/man/repo-sync.1
index 8f145a09e..4e115e200 100644
--- a/man/repo-sync.1
+++ b/man/repo-sync.1
@@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man.
-.TH REPO "1" "August 2025" "repo sync" "Repo Manual"
+.TH REPO "1" "May 2026" "repo sync" "Repo Manual"
 .SH NAME
 repo \- repo sync - manual page for repo sync
 .SH SYNOPSIS
@@ -101,6 +101,10 @@ implies \fB\-c\fR
 \fB\-\-no\-use\-superproject\fR
 disable use of manifest superprojects
 .TP
+\fB\-\-superproject\-revision\fR=\fI\,SUPERPROJECT_REVISION\/\fR
+sync to superproject revision (applies to outer
+manifest)
+.TP
 \fB\-\-tags\fR
 fetch tags
 .TP
diff --git a/subcmds/sync.py b/subcmds/sync.py
index 8c2591180..7e0e7418c 100644
--- a/subcmds/sync.py
+++ b/subcmds/sync.py
@@ -64,6 +64,7 @@ from error import SyncError
 from error import UpdateManifestError
 import event_log
 from git_command import git_require
+from git_command import GitCommand
 from git_config import GetUrlCookieFile
 from git_refs import HEAD
 from git_refs import R_HEADS
@@ -565,6 +566,11 @@ later is required to fix a server side protocol bug.
             dest="use_superproject",
             help="disable use of manifest superprojects",
         )
+        p.add_option(
+            "--superproject-revision",
+            action="store",
+            help="sync to superproject revision (applies to outer manifest)",
+        )
         p.add_option("--tags", action="store_true", help="fetch tags")
         p.add_option(
             "--no-tags",
@@ -668,6 +674,24 @@ later is required to fix a server side protocol bug.
             or opt.current_branch_only
         )
 
+    def _ConfigureSuperproject(
+        self,
+        opt: optparse.Values,
+        manifest,
+        revision: Optional[str] = None,
+    ) -> bool:
+        """Configure superproject with options."""
+        if not manifest.superproject:
+            return False
+        manifest.superproject.SetQuiet(not opt.verbose)
+        print_messages = git_superproject.PrintMessages(
+            opt.use_superproject, manifest
+        )
+        manifest.superproject.SetPrintMessages(print_messages)
+        if revision:
+            manifest.superproject.SetRevisionId(revision)
+        return print_messages
+
     def _UpdateProjectsRevisionId(
         self, opt, args, superproject_logging_data, manifest
     ):
@@ -741,11 +765,7 @@ later is required to fix a server side protocol bug.
 
             if not use_super:
                 continue
-            m.superproject.SetQuiet(not opt.verbose)
-            print_messages = git_superproject.PrintMessages(
-                opt.use_superproject, m
-            )
-            m.superproject.SetPrintMessages(print_messages)
+            print_messages = self._ConfigureSuperproject(opt, m)
             update_result = m.superproject.UpdateProjectsRevisionId(
                 per_manifest[m.path_prefix], git_event_log=self.git_event_log
             )
@@ -1832,7 +1852,11 @@ later is required to fix a server side protocol bug.
             mp: the manifestProject to query.
             manifest_name: Manifest file to be reloaded.
         """
-        if not mp.standalone_manifest_url:
+        if opt.superproject_revision and mp.manifest == self.outer_manifest:
+            self._SyncToSuperprojectRev(
+                opt, mp.manifest, mp, manifest_name, errors
+            )
+        elif not mp.standalone_manifest_url:
             self._UpdateManifestProject(opt, mp, manifest_name, errors)
 
         if mp.manifest.submanifests:
@@ -2041,6 +2065,53 @@ later is required to fix a server side protocol bug.
         if not success:
             print("Warning: post-sync hook reported failure.")
 
+    def _SyncToSuperprojectRev(
+        self,
+        opt: optparse.Values,
+        manifest,
+        mp: Project,
+        manifest_name: Optional[str],
+        errors: List[Exception],
+    ) -> None:
+        """Sync to a specific superproject commit."""
+        if not manifest.superproject:
+            raise SyncError("superproject not defined in manifest")
+
+        self._ConfigureSuperproject(
+            opt, manifest, revision=opt.superproject_revision
+        )
+
+        sync_result = manifest.superproject.Sync(self.git_event_log)
+        if not sync_result.success:
+            raise SyncError("failed to sync superproject")
+
+        cmd = ["show", f"{opt.superproject_revision}:.supermanifest"]
+        p = GitCommand(
+            None,
+            cmd,
+            gitdir=manifest.superproject._work_git,
+            bare=True,
+            capture_stdout=True,
+            capture_stderr=True,
+        )
+        if p.Wait() != 0:
+            raise SyncError(
+                f"failed to read .supermanifest from superproject: {p.stderr}"
+            )
+
+        try:
+            _, _, manifest_commit = p.stdout.strip().split()
+        except ValueError:
+            raise SyncError("could not parse .supermanifest")
+
+        mp.SetRevision(manifest_commit)
+        try:
+            self._UpdateManifestProject(opt, mp, manifest_name, errors)
+        except UpdateManifestError as e:
+            raise SyncError(
+                "failed to sync manifest project", aggregate_errors=[e]
+            )
+
     def _ExecuteHelper(self, opt, args, errors):
         manifest = self.outer_manifest
         if not opt.outer_manifest:
@@ -2099,7 +2170,7 @@ later is required to fix a server side protocol bug.
             ):
                 mp.ConfigureCloneFilterForDepth("blob:none")
 
-        if opt.mp_update:
+        if opt.mp_update or opt.superproject_revision:
             self._UpdateAllManifestProjects(opt, mp, manifest_name, errors)
         else:
             print("Skipping update of local manifest project.")
diff --git a/tests/test_subcmds_sync.py b/tests/test_subcmds_sync.py
index ef162392b..785c0e629 100644
--- a/tests/test_subcmds_sync.py
+++ b/tests/test_subcmds_sync.py
@@ -1286,3 +1286,171 @@ class UpdateCopyLinkfileListTest(unittest.TestCase):
         self.assertFalse(os.path.lexists(os.path.join(llms_dir, "rules")))
         self.assertTrue(os.path.exists(os.path.join(llms_dir, "my-notes.txt")))
         self.assertTrue(os.path.isdir(llms_dir))
+
+
+class SyncToSuperprojectRevTests(unittest.TestCase):
+    """Tests for Sync._SyncToSuperprojectRev."""
+
+    def setUp(self):
+        self.repodir = tempfile.mkdtemp(".repo")
+        self.manifest = mock.MagicMock(repodir=self.repodir)
+        self.manifest.superproject = mock.MagicMock()
+        self.manifest.path_prefix = ""
+
+        self.mp = mock.MagicMock()
+        self.cmd = sync.Sync(manifest=self.manifest)
+        self.cmd.outer_manifest = self.manifest
+
+        self.opt = mock.Mock()
+        self.opt.verbose = False
+        self.opt.superproject_revision = "deadbeef"
+        self.opt.mp_update = True
+
+        self.errors = []
+
+    def tearDown(self):
+        shutil.rmtree(self.repodir)
+
+    @mock.patch("subcmds.sync.GitCommand")
+    def test_successful_sync(self, mock_git_command):
+        """Test successful sync to superproject rev."""
+        mock_superproject = self.manifest.superproject
+        mock_superproject.Sync.return_value = mock.Mock(success=True)
+
+        mock_git = mock.Mock()
+        mock_git.Wait.return_value = 0
+        mock_git.stdout = "proj branch manifest_commit_hash\n"
+        mock_git_command.return_value = mock_git
+
+        with mock.patch.object(
+            self.cmd, "_UpdateManifestProject"
+        ) as mock_update:
+            self.cmd._SyncToSuperprojectRev(
+                self.opt, self.manifest, self.mp, "name", self.errors
+            )
+
+            mock_superproject.SetRevisionId.assert_called_with("deadbeef")
+            mock_superproject.Sync.assert_called_once()
+            mock_git_command.assert_called_once()
+            self.mp.SetRevision.assert_called_with("manifest_commit_hash")
+            mock_update.assert_called_once()
+            self.assertEqual(self.errors, [])
+
+    @mock.patch("subcmds.sync.GitCommand")
+    def test_parse_error(self, mock_git_command):
+        """Test error when .supermanifest cannot be parsed."""
+        mock_superproject = self.manifest.superproject
+        mock_superproject.Sync.return_value = mock.Mock(success=True)
+
+        mock_git = mock.Mock()
+        mock_git.Wait.return_value = 0
+        # Invalid format (not 3 parts)
+        mock_git.stdout = "invalid_content\n"
+        mock_git_command.return_value = mock_git
+
+        with self.assertRaises(sync.SyncError) as e:
+            self.cmd._SyncToSuperprojectRev(
+                self.opt, self.manifest, self.mp, "name", self.errors
+            )
+        self.assertIn("could not parse .supermanifest", str(e.exception))
+
+    @mock.patch("subcmds.sync.GitCommand")
+    def test_read_error(self, mock_git_command):
+        """Test error when reading .supermanifest fails."""
+        mock_superproject = self.manifest.superproject
+        mock_superproject.Sync.return_value = mock.Mock(success=True)
+
+        mock_git = mock.Mock()
+        mock_git.Wait.return_value = 1
+        mock_git.stderr = "git error"
+        mock_git_command.return_value = mock_git
+
+        with self.assertRaises(sync.SyncError) as e:
+            self.cmd._SyncToSuperprojectRev(
+                self.opt, self.manifest, self.mp, "name", self.errors
+            )
+        self.assertIn("failed to read .supermanifest", str(e.exception))
+
+    def test_no_superproject(self):
+        """Test error when superproject is not defined."""
+        self.manifest.superproject = None
+
+        with self.assertRaises(sync.SyncError) as e:
+            self.cmd._SyncToSuperprojectRev(
+                self.opt, self.manifest, self.mp, "name", self.errors
+            )
+        self.assertIn("superproject not defined", str(e.exception))
+
+    @mock.patch("subcmds.sync.GitCommand")
+    def test_sync_failure(self, mock_git_command):
+        """Test error when superproject sync fails."""
+        mock_superproject = self.manifest.superproject
+        mock_superproject.Sync.return_value = mock.Mock(success=False)
+
+        with self.assertRaises(sync.SyncError) as e:
+            self.cmd._SyncToSuperprojectRev(
+                self.opt, self.manifest, self.mp, "name", self.errors
+            )
+        self.assertIn("failed to sync superproject", str(e.exception))
+
+
+class UpdateAllManifestProjectsTests(unittest.TestCase):
+    """Tests for Sync._UpdateAllManifestProjects."""
+
+    def setUp(self):
+        self.repodir = tempfile.mkdtemp(".repo")
+        self.manifest = mock.MagicMock(repodir=self.repodir)
+        self.manifest.superproject = mock.MagicMock()
+        self.manifest.path_prefix = ""
+        self.manifest.standalone_manifest_url = None
+        self.manifest.submanifests = {}
+
+        self.mp = mock.MagicMock()
+        self.mp.manifest = self.manifest
+        self.mp.standalone_manifest_url = None
+        self.cmd = sync.Sync(manifest=self.manifest)
+        self.cmd.outer_manifest = self.manifest
+
+        self.opt = mock.Mock()
+        self.opt.verbose = False
+        self.opt.superproject_revision = None
+        self.opt.mp_update = True
+
+        self.errors = []
+
+    def tearDown(self):
+        shutil.rmtree(self.repodir)
+
+    def test_superproject_revision_outer_manifest(self):
+        """Test that _SyncToSuperprojectRev is called for outer manifest."""
+        self.opt.superproject_revision = "deadbeef"
+
+        with mock.patch.object(
+            self.cmd, "_SyncToSuperprojectRev"
+        ) as mock_sync_to_rev:
+            self.cmd._UpdateAllManifestProjects(
+                self.opt, self.mp, "name", self.errors
+            )
+            mock_sync_to_rev.assert_called_once_with(
+                self.opt, self.manifest, self.mp, "name", self.errors
+            )
+
+    def test_superproject_revision_submanifest(self):
+        """Test that _SyncToSuperprojectRev is NOT called for submanifest."""
+        self.opt.superproject_revision = "deadbeef"
+        submanifest = mock.MagicMock()
+        submanifest.path_prefix = "sub/"
+        submanifest.standalone_manifest_url = None
+        self.mp.manifest = submanifest
+
+        with mock.patch.object(
+            self.cmd, "_SyncToSuperprojectRev"
+        ) as mock_sync_to_rev:
+            with mock.patch.object(
+                self.cmd, "_UpdateManifestProject"
+            ) as mock_update_manifest:
+                self.cmd._UpdateAllManifestProjects(
+                    self.opt, self.mp, "name", self.errors
+                )
+                mock_sync_to_rev.assert_not_called()
+                mock_update_manifest.assert_called_once()