project: check upstream ref ancestry for non-shallow clones

In _CheckForImmutableRevision, commit d9cc0a15 restricted upstream ref
validation strictly to superprojects (if use_superproject) to prevent
shallow clones with an upstream attribute from failing ancestry checks
and falling back to full clones.

However, restricting this check exclusively to superprojects broke
non-shallow projects with pinned immutable revisions (such as in Smart
Sync, `repo sync -t <BUILD_ID>`, or pinned manifests): When the target
commit already exists in the local Git object store (for instance,
prefetched into refs/prefetch/ by a background daemon or via shared
object dirs), _CheckForImmutableRevision returned True without verifying
that the local tracking ref (refs/remotes/<remote>/<upstream>) is
present and reaches the revision. As a result, _RemoteFetch skipped
fetching the upstream branch, leaving the local tracking ref stale or
missing. Subsequent `repo start` branches tracking that remote branch
diverged, causing `repo upload` to attempt uploading all intermediate
commits between the stale tracking ref and HEAD.

Restore upstream ancestry validation in _CheckForImmutableRevision for
non-shallow projects when upstream is specified. Also pass the sync
depth into _CheckForImmutableRevision call sites so shallow checkouts
continue to skip upstream verification and avoid triggering un-shallow
fallbacks.

Test: PYTHONPATH=. pytest tests/test_project.py
Change-Id: Ib5bdf41810bb06c8ed053447209ddc2e488f3913
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/624361
Tested-by: Rahul Yadav <yadavrah@google.com>
Commit-Queue: Rahul Yadav <yadavrah@google.com>
Reviewed-by: Gavin Mak <gavinmak@google.com>

color.py

@@ -84,9 +84,14 @@ def _Color(fg=None, bg=None, attr=None):
 
 DEFAULT = None
 
+
+class _CheckConsoleSentinel:
+    """Sentinel for checking console coloring."""
+
+
 # Placholder value that indicates we need to check if the user is in an
 # interactive terminal session to determine if we turn on color or not.
-_CHECK_CONSOLE = object()
+_CHECK_CONSOLE = _CheckConsoleSentinel()
 
 # https://git-scm.com/docs/git-config#Documentation/git-config.txt-colorui
 _CONFIG_TO_COLOR_SETTING = {

command.py

@@ -17,6 +17,7 @@ import multiprocessing
 import optparse
 import os
 import re
+from typing import TYPE_CHECKING
 
 from error import InvalidProjectGroupsError
 from error import NoSuchProjectError
@@ -25,6 +26,10 @@ from event_log import EventLog
 import progress
 
 
+if TYPE_CHECKING:
+    from project import Project
+
+
 # Are we generating man-pages?
 GENERATE_MANPAGES = os.environ.get("_REPO_GENERATE_MANPAGES_") == " indeed! "
 
@@ -61,6 +66,10 @@ class Command:
     # command to show short-vs-full summaries.
     COMMON = False
 
+    # Whether this command should respect the smart sync override manifest if
+    # it exists.
+    RESPECT_SMART_SYNC_OVERRIDE = True
+
     # Whether this command supports running in parallel. If greater than 0,
     # it is the number of parallel jobs to default to.
     PARALLEL_JOBS = None
@@ -242,6 +251,12 @@ class Command:
             # from the user's perspective.
             opt.outer_manifest = True
 
+        if self.RESPECT_SMART_SYNC_OVERRIDE:
+            if self.manifest:
+                self.TryOverrideManifestWithSmartSync(self.manifest)
+            if self.outer_manifest and self.outer_manifest != self.manifest:
+                self.TryOverrideManifestWithSmartSync(self.outer_manifest)
+
     def ValidateOptions(self, opt, args):
         """Validate the user options & arguments before executing.
 
@@ -375,7 +390,7 @@ class Command:
         manifest=None,
         groups="",
         missing_ok=False,
-        submodules_ok=False,
+        submodules_ok=None,
         all_manifests=False,
     ):
         """A list of projects that match the arguments.
@@ -385,7 +400,9 @@ class Command:
             manifest: an XmlManifest, the manifest to use, or None for default.
             groups: a string, the manifest groups in use.
             missing_ok: a boolean, whether to allow missing projects.
-            submodules_ok: a boolean, whether to allow submodules.
+            submodules_ok: whether to allow submodules. True allows them for
+                all projects, False disallows them for all projects, and None
+                defers to each project's sync-s setting.
             all_manifests: a boolean, if True then all manifests and
                 submanifests are used. If False, then only the local
                 (sub)manifest is used.
@@ -403,6 +420,11 @@ class Command:
             all_projects_list = manifest.projects
         result = []
 
+        def should_include_submodules(project: "Project") -> bool:
+            if submodules_ok is None:
+                return project.sync_s
+            return submodules_ok
+
         if not groups:
             groups = manifest.GetManifestGroupsStr()
         groups = [x for x in re.split(r"[,\s]+", groups) if x]
@@ -410,7 +432,7 @@ class Command:
         if not args:
             derived_projects = {}
             for project in all_projects_list:
-                if submodules_ok or project.sync_s:
+                if should_include_submodules(project):
                     derived_projects.update(
                         (p.RelPath(local=False), p)
                         for p in project.GetDerivedSubprojects()
@@ -452,7 +474,7 @@ class Command:
                     if (
                         project
                         and not project.Derived
-                        and (submodules_ok or project.sync_s)
+                        and should_include_submodules(project)
                     ):
                         search_again = False
                         for subproject in project.GetDerivedSubprojects():

completion.zsh

@@ -322,7 +322,10 @@ _repo() {
         '--no-clone-bundle[Do not use clone bundle]' \
         '(-u --manifest-server-username)'{-u,--manifest-server-username=}'[Username for manifest server]:username:' \
         '(-p --manifest-server-password)'{-p,--manifest-server-password=}'[Password for manifest server]:password:' \
-        '--fetch-submodules[Fetch submodules]' \
+        '--recurse-submodules[Sync submodules]' \
+        '--no-recurse-submodules[Do not sync submodules]' \
+        '--fetch-submodules[Deprecated alias for --recurse-submodules]' \
+        '--no-fetch-submodules[Deprecated alias for --no-recurse-submodules]' \
         '--use-superproject[Use superproject]' \
         '--no-use-superproject[Do not use superproject]' \
         '--tags[Sync tags]' \
@@ -397,6 +400,7 @@ _repo() {
         '--no-verify[Do not verify]' \
         '--verify[Verify]' \
         '--ignore-hooks[Ignore hooks]' \
+        '--fix[Automatically fix]' \
         '*: :->project'
       ;;
     version)

docs/repo-hooks.md

@@ -83,6 +83,20 @@ then check it directly.  Hooks should not normally modify the active git repo
 the user.  Although user interaction is discouraged in the common case, it can
 be useful when deploying automatic fixes.
 
+### Safe Prompts
+
+If the repo command that triggered the hook supports a "yes" option (e.g.,
+`repo upload --yes`), this option is propagated to the hook's `main` function
+as `yes` parameter (defaulting to `False`).  Hooks can use this to bypass
+interactive confirmation prompts for safe non-modifying operations.
+
+### Automated Fixes
+
+If the repo command that triggered the hook supports a "fix" option (e.g.,
+`repo upload --fix`), this option is propagated to the hook's `main` function
+as `fix` parameter (defaulting to `False`).  Hooks can use this to automatically
+apply fixes without prompting the user.
+
 ### Shebang Handling
 
 *** note
@@ -119,7 +133,7 @@ This hook runs when people run `repo upload`.
 The `pre-upload.py` file should be defined like:
 
 ```py
-def main(project_list, worktree_list=None, **kwargs):
+def main(project_list, worktree_list=None, fix=False, yes=False, **kwargs):
     """Main function invoked directly by repo.
 
     We must use the name "main" as that is what repo requires.
@@ -130,6 +144,9 @@ def main(project_list, worktree_list=None, **kwargs):
           project_list, so that each entry in project_list matches with a
           directory in worktree_list.  If None, we will attempt to calculate
           the directories automatically.
+      fix: Whether to automatically apply fixes without prompting.
+      yes: Whether to answer yes to all safe prompts (see
+          [Safe Prompts](#safe-prompts)).
       kwargs: Leave this here for forward-compatibility.
     """
 ```

git_command.py

@@ -70,6 +70,19 @@ class _GitCall:
 git = _GitCall()
 
 
+def IsValidBranchName(name: str) -> bool:
+    """Return whether |name| is valid where Git expects a branch name."""
+    p = GitCommand(
+        None,
+        ["check-ref-format", "--branch", name],
+        capture_stdout=True,
+        capture_stderr=True,
+        add_event_log=False,
+        log_as_error=False,
+    )
+    return p.Wait() == 0
+
+
 def RepoSourceVersion():
     """Return the version of the repo.git tree."""
     ver = getattr(RepoSourceVersion, "version", None)

git_config.py

@@ -40,7 +40,7 @@ from repo_trace import Trace
 # that is saved in the config.
 SYNC_STATE_PREFIX = "repo.syncstate."
 
-ID_RE = re.compile(r"^[0-9a-f]{40,64}$")
+ID_RE = re.compile(r"^(?:[0-9a-f]{40}|[0-9a-f]{64})$")
 
 REVIEW_CACHE = {}
 

git_refs.py

@@ -14,6 +14,7 @@
 
 import os
 
+from git_command import git_require
 from git_command import GitCommand
 import platform_utils
 from repo_trace import Trace
@@ -41,6 +42,17 @@ class GitRefs:
         self._EnsureLoaded()
         return self._phyref
 
+    @property
+    def head(self) -> str:
+        """Return HEAD's symbolic target or detached object ID."""
+        self._EnsureLoaded()
+        return self._symref.get(HEAD) or self._phyref.get(HEAD, "")
+
+    @property
+    def is_loaded(self) -> bool:
+        """Whether a ref snapshot has already been loaded."""
+        return self._phyref is not None
+
     def get(self, name):
         try:
             return self.all[name]
@@ -87,8 +99,12 @@ class GitRefs:
             self._symref = {}
             self._mtime = {}
 
-            self._ReadRefs()
-            self._ReadSymbolicRef(HEAD)
+            root_refs_loaded = self._ReadRefs()
+            if not root_refs_loaded or (
+                HEAD not in self._phyref and HEAD not in self._symref
+            ):
+                # --include-root-refs does not report an unborn HEAD.
+                self._ReadSymbolicRef(HEAD)
 
             scan = self._symref
             attempts = 0
@@ -113,18 +129,32 @@ class GitRefs:
         """Check if a ref_id is a null object ID."""
         return ref_id and all(ch == "0" for ch in ref_id)
 
-    def _ReadRefs(self) -> None:
-        """Read all references using git for-each-ref."""
+    def _ReadRefs(self) -> bool:
+        """Read all references using git for-each-ref.
+
+        Returns:
+            Whether root refs, including HEAD when it exists, were loaded.
+        """
+        include_root_refs = git_require((2, 45, 0))
+        cmd = [
+            "for-each-ref",
+            "--format=%(objectname)%00%(refname)%00%(symref)",
+        ]
+        if include_root_refs:
+            cmd.insert(1, "--include-root-refs")
+            # Avoid caching volatile root refs such as ORIG_HEAD.  HEAD and
+            # refs/* are the only namespaces GitRefs exposes to callers.
+            cmd.extend([HEAD, "refs"])
         p = GitCommand(
             None,
-            ["for-each-ref", "--format=%(objectname)%00%(refname)%00%(symref)"],
+            cmd,
             capture_stdout=True,
             capture_stderr=True,
             bare=True,
             gitdir=self._gitdir,
         )
         if p.Wait() != 0:
-            return
+            return False
 
         for line in p.stdout.splitlines():
             ref_id, name, symref = line.split("\0")
@@ -132,6 +162,7 @@ class GitRefs:
                 self._symref[name] = symref
             elif ref_id and not self._IsNullRef(ref_id):
                 self._phyref[name] = ref_id
+        return include_root_refs
 
     def _ReadSymbolicRef(self, name: str) -> None:
         """Read a symbolic reference."""

git_superproject.py

@@ -36,7 +36,6 @@ 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
 
 
@@ -189,7 +188,7 @@ class Superproject:
             if netloc:
                 parts = netloc.split("-review", 1)
                 host = parts[0]
-                rev = GitRefs(self._work_git).get("HEAD")
+                rev = self._GetRef("HEAD")
                 return f"{host}/{self.name}@{rev}"
         return None
 
@@ -314,7 +313,10 @@ class Superproject:
         # We use --negotiation-tip to speed up the fetch. Superproject branches
         # do not share commits. So this lets git know it only needs to send
         # commits reachable from the specified local refs.
-        rev_commit = GitRefs(self._work_git).get(f"refs/heads/{self.revision}")
+        negotiation_ref = self.revision
+        if negotiation_ref and not negotiation_ref.startswith("refs/"):
+            negotiation_ref = f"refs/heads/{negotiation_ref}"
+        rev_commit = self._GetRef(negotiation_ref) if negotiation_ref else ""
         if rev_commit:
             cmd.extend(["--negotiation-tip", rev_commit])
 
@@ -347,6 +349,21 @@ class Superproject:
             return False
         return True
 
+    def _GetRef(self, ref: str) -> str:
+        """Resolve one local ref without loading the entire ref namespace."""
+        p = GitCommand(
+            None,
+            ["rev-parse", "--verify", "--quiet", ref],
+            gitdir=self._work_git,
+            bare=True,
+            capture_stdout=True,
+            capture_stderr=True,
+            log_as_error=False,
+        )
+        if p.Wait() == 0:
+            return p.stdout.strip()
+        return ""
+
     def _LsTree(self):
         """Gets the commit ids for all projects.
 
@@ -473,7 +490,7 @@ class Superproject:
             )
             return None
         manifest_str = self._manifest.ToXml(
-            filter_groups=self._manifest.GetManifestGroupsStr(),
+            filter_groups="all",
             omit_local=True,
         ).toxml()
         manifest_path = self._manifest_path

hooks.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import optparse
 import os
 import re
 import sys
@@ -68,6 +69,8 @@ class RepoHook:
         allow_all_hooks=False,
         ignore_hooks=False,
         abort_if_user_denies=False,
+        yes=False,
+        fix=False,
     ):
         """RepoHook constructor.
 
@@ -89,6 +92,8 @@ class RepoHook:
             ignore_hooks: If True, then 'Do not abort action if hooks fail'.
             abort_if_user_denies: If True, we'll abort running the hook if the
                 user doesn't allow us to run the hook.
+            yes: If True, then 'Yes' is assumed for any prompts.
+            fix: If True, then 'Fix' is assumed for any fixup prompts.
         """
         self._hook_type = hook_type
         self._hooks_project = hooks_project
@@ -99,6 +104,8 @@ class RepoHook:
         self._allow_all_hooks = allow_all_hooks
         self._ignore_hooks = ignore_hooks
         self._abort_if_user_denies = abort_if_user_denies
+        self._yes = yes
+        self._fix = fix
 
         # Store the full path to the script for convenience.
         self._script_fullpath = None
@@ -374,8 +381,12 @@ class RepoHook:
             #   def main(project_list, **kwargs):
             #
             # This allows us to later expand the API without breaking old hooks.
-            kwargs = kwargs.copy()
-            kwargs["hook_should_take_kwargs"] = True
+            kwargs = {
+                **kwargs,
+                "hook_should_take_kwargs": True,
+                "fix": self._fix,
+                "yes": self._yes,
+            }
 
             # See what version of python the hook has been written against.
             data = open(self._script_fullpath).read()
@@ -497,12 +508,18 @@ class RepoHook:
                     "origin"
                 ).url,
                 "bug_url": manifest.contactinfo.bugurl,
+                "yes": getattr(opt, "yes", False),
+                "fix": getattr(opt, "fix", False),
             }
         )
         return cls(*args, **kwargs)
 
     @staticmethod
-    def AddOptionGroup(parser, name):
+    def AddOptionGroup(
+        parser: optparse.OptionParser,
+        name: str,
+        allow_fix: bool = False,
+    ) -> None:
         """Help options relating to the various hooks."""
 
         # Note that verify and no-verify are NOT opposites of each other, which
@@ -526,3 +543,10 @@ class RepoHook:
             action="store_true",
             help="Do not abort if %s hooks fail." % name,
         )
+        if allow_fix:
+            group.add_option(
+                "--fix",
+                action="store_true",
+                default=False,
+                help="Automatically apply %s fixes without prompting." % name,
+            )

man/repo-smartsync.1

@@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man.
-.TH REPO "1" "June 2026" "repo smartsync" "Repo Manual"
+.TH REPO "1" "July 2026" "repo smartsync" "Repo Manual"
 .SH NAME
 repo \- repo smartsync - manual page for repo smartsync
 .SH SYNOPSIS
@@ -68,6 +68,9 @@ fetch all branches from server
 \fB\-m\fR NAME.xml, \fB\-\-manifest\-name\fR=\fI\,NAME\/\fR.xml
 temporary manifest to use for this sync
 .TP
+\fB\-g\fR GROUP, \fB\-\-groups\fR=\fI\,GROUP\/\fR
+sync projects matching the specific groups.  Not persistent unlike when used on init
+.TP
 \fB\-\-clone\-bundle\fR
 enable use of \fI\,/clone.bundle\/\fP on HTTP/HTTPS
 .TP
@@ -80,8 +83,11 @@ username to authenticate with the manifest server
 \fB\-p\fR MANIFEST_SERVER_PASSWORD, \fB\-\-manifest\-server\-password\fR=\fI\,MANIFEST_SERVER_PASSWORD\/\fR
 password to authenticate with the manifest server
 .TP
-\fB\-\-fetch\-submodules\fR
-fetch submodules from server
+\fB\-\-recurse\-submodules\fR
+sync submodules from server
+.TP
+\fB\-\-no\-recurse\-submodules\fR
+don't sync submodules from server
 .TP
 \fB\-\-use\-superproject\fR
 use the manifest superproject to sync projects; implies \fB\-c\fR

man/repo-sync.1

@@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man.
-.TH REPO "1" "June 2026" "repo sync" "Repo Manual"
+.TH REPO "1" "July 2026" "repo sync" "Repo Manual"
 .SH NAME
 repo \- repo sync - manual page for repo sync
 .SH SYNOPSIS
@@ -68,6 +68,9 @@ fetch all branches from server
 \fB\-m\fR NAME.xml, \fB\-\-manifest\-name\fR=\fI\,NAME\/\fR.xml
 temporary manifest to use for this sync
 .TP
+\fB\-g\fR GROUP, \fB\-\-groups\fR=\fI\,GROUP\/\fR
+sync projects matching the specific groups.  Not persistent unlike when used on init
+.TP
 \fB\-\-clone\-bundle\fR
 enable use of \fI\,/clone.bundle\/\fP on HTTP/HTTPS
 .TP
@@ -80,8 +83,11 @@ username to authenticate with the manifest server
 \fB\-p\fR MANIFEST_SERVER_PASSWORD, \fB\-\-manifest\-server\-password\fR=\fI\,MANIFEST_SERVER_PASSWORD\/\fR
 password to authenticate with the manifest server
 .TP
-\fB\-\-fetch\-submodules\fR
-fetch submodules from server
+\fB\-\-recurse\-submodules\fR
+sync submodules from server
+.TP
+\fB\-\-no\-recurse\-submodules\fR
+don't sync submodules from server
 .TP
 \fB\-\-use\-superproject\fR
 use the manifest superproject to sync projects; implies \fB\-c\fR
@@ -212,8 +218,12 @@ bootstrap a new Git repository from a resumeable bundle file on a content
 delivery network. This may be necessary if there are problems with the local
 Python HTTP client or proxy configuration, but the Git binary works.
 .PP
-The \fB\-\-fetch\-submodules\fR option enables fetching Git submodules of a project from
-server.
+The \fB\-\-recurse\-submodules\fR option enables syncing Git submodules of all projects
+from the server. The \fB\-\-no\-recurse\-submodules\fR option disables syncing Git
+submodules, even when a project has sync\-s="true" in the manifest.
+.PP
+The \fB\-\-fetch\-submodules\fR and \fB\-\-no\-fetch\-submodules\fR options are deprecated aliases
+for \fB\-\-recurse\-submodules\fR and \fB\-\-no\-recurse\-submodules\fR, respectively.
 .PP
 The \fB\-c\fR/\-\-current\-branch option can be used to only fetch objects that are on the
 branch specified by a project's revision.

man/repo-upload.1

@@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man.
-.TH REPO "1" "June 2026" "repo upload" "Repo Manual"
+.TH REPO "1" "August 2026" "repo upload" "Repo Manual"
 .SH NAME
 repo \- repo upload - manual page for repo upload
 .SH SYNOPSIS
@@ -112,6 +112,9 @@ Run the pre\-upload hook without prompting.
 .TP
 \fB\-\-ignore\-hooks\fR
 Do not abort if pre\-upload hooks fail.
+.TP
+\fB\-\-fix\fR
+Automatically apply pre\-upload fixes without prompting.
 .PP
 Run `repo help upload` to view the detailed manual.
 .SH DETAILS

manifest_xml.py

@@ -692,9 +692,9 @@ https://gerrit.googlesource.com/git-repo/+/HEAD/docs/manifest-format.md
                 e.setAttribute("remote", remoteName)
             if peg_rev:
                 if self.IsMirror:
-                    value = p.bare_git.rev_parse(p.revisionExpr + "^0")
+                    value = p.bare_git.ResolveCommit(p.revisionExpr)
                 else:
-                    value = p.work_git.rev_parse(HEAD + "^0")
+                    value = p.work_git.ResolveCommit(HEAD)
                 e.setAttribute("revision", value)
                 if peg_rev_upstream:
                     if p.upstream:

project.py

@@ -15,6 +15,7 @@
 import datetime
 import errno
 import filecmp
+import functools
 import glob
 import os
 import platform
@@ -194,6 +195,10 @@ class ReviewableBranch:
     def name(self):
         return self.branch.name
 
+    @property
+    def current(self) -> bool:
+        return getattr(self.branch, "current", False)
+
     @property
     def commits(self):
         if self._commit_cache is None:
@@ -238,6 +243,12 @@ class ReviewableBranch:
             "--pretty=format:%cd", "-n", "1", R_HEADS + self.name, "--"
         )
 
+    @property
+    def modified_files(self) -> List[str]:
+        return self.project.bare_git.diff(
+            "--name-only", f"{self.base}...{R_HEADS}{self.name}"
+        ).splitlines()
+
     @property
     def base_exists(self):
         """Whether the branch we're tracking exists.
@@ -270,7 +281,8 @@ class ReviewableBranch:
         validate_certs=True,
         push_options=None,
         patchset_description=None,
-    ):
+        git_event_log: Optional[EventLog] = None,
+    ) -> None:
         self.project.UploadForReview(
             branch=self.name,
             people=people,
@@ -286,6 +298,7 @@ class ReviewableBranch:
             validate_certs=validate_certs,
             push_options=push_options,
             patchset_description=patchset_description,
+            git_event_log=git_event_log,
         )
 
     def GetPublishedRefs(self):
@@ -567,6 +580,7 @@ class Project:
         parent=None,
         use_git_worktrees=False,
         is_derived=False,
+        gitlink_path: Optional[str] = None,
         dest_branch=None,
         optimized_fetch=False,
         retry_fetches=0,
@@ -596,6 +610,8 @@ class Project:
             use_git_worktrees: Whether to use `git worktree` for this project.
             is_derived: False if the project was explicitly defined in the
                 manifest; True if the project is a discovered submodule.
+            gitlink_path: For a discovered submodule, its path inside the
+                parent project.
             dest_branch: The branch to which to push changes for review by
                 default.
             optimized_fetch: If True, when a project is set to a sha1 revision,
@@ -623,6 +639,7 @@ class Project:
         # See the XmlManifest init code for more info.
         self.use_git_worktrees = use_git_worktrees
         self.is_derived = is_derived
+        self.gitlink_path = gitlink_path
         self.optimized_fetch = optimized_fetch
         self.retry_fetches = max(0, retry_fetches)
         self.subprojects = []
@@ -757,15 +774,28 @@ class Project:
         work_git is otheriwse inaccessible (e.g. an incomplete sync).
         """
         try:
-            b = self.work_git.GetHead()
+            b = self._GetHead()
         except NoManifestException:
             # If the local checkout is in a bad state, don't barf.  Let the
             # callers process this like the head is unreadable.
             return None
-        if b.startswith(R_HEADS):
+        if b and b.startswith(R_HEADS):
             return b[len(R_HEADS) :]
         return None
 
+    def _GetHead(self) -> Optional[str]:
+        """Return worktree HEAD, reusing a compatible loaded ref snapshot."""
+        if not self.work_git:
+            return None
+        # Git worktrees keep the checkout's HEAD in the worktree admin dir,
+        # while bare_ref reads the shared repository.  Its HEAD is not the
+        # checked-out worktree's HEAD and must not be reused here.
+        if not self.use_git_worktrees and self.bare_ref.is_loaded:
+            head = self.bare_ref.head
+            if head:
+                return head
+        return self.work_git.GetHead()
+
     def IsRebaseInProgress(self):
         """Returns true if a rebase or "am" is in progress"""
         # "rebase-apply" is used for "git rebase".
@@ -864,8 +894,8 @@ class Project:
 
     def GetBranches(self):
         """Get all existing local branches."""
-        current = self.CurrentBranch
         all_refs = self._allrefs
+        current = self.CurrentBranch
         heads = {}
 
         for name, ref_id in all_refs.items():
@@ -1141,24 +1171,37 @@ class Project:
 
     def GetUploadableBranches(self, selected_branch=None):
         """List any branches which can be uploaded for review."""
-        heads = {}
-        pubed = {}
+        if selected_branch:
+            branch = self.GetBranch(selected_branch)
+            if not branch.LocalMerge:
+                return []
+            head_id = self.bare_ref.get(R_HEADS + selected_branch)
+            if not head_id:
+                return []
+            pub_id = self.bare_ref.get(R_PUB + selected_branch)
+            if pub_id and pub_id == head_id:
+                return []
+            rb = self.GetUploadableBranch(selected_branch)
+            if rb:
+                rb.branch.current = selected_branch == self.CurrentBranch
+                return [rb]
+            return []
 
-        for name, ref_id in self._allrefs.items():
-            if name.startswith(R_HEADS):
-                heads[name[len(R_HEADS) :]] = ref_id
-            elif name.startswith(R_PUB):
-                pubed[name[len(R_PUB) :]] = ref_id
+        # Optimization: Skip scanning _allrefs (which spawns git processes)
+        # if no local branches with upstream tracking exist in .git/config.
+        if not any(self.config.GetSubSections("branch")):
+            return []
+
+        branches = self.GetBranches()
 
         ready = []
-        for branch, ref_id in heads.items():
-            if branch in pubed and pubed[branch] == ref_id:
-                continue
-            if selected_branch and branch != selected_branch:
+        for branch, branch_config in branches.items():
+            if branch_config.published == branch_config.revision:
                 continue
 
             rb = self.GetUploadableBranch(branch)
             if rb:
+                rb.branch.current = branch_config.current
                 ready.append(rb)
         return ready
 
@@ -1188,7 +1231,8 @@ class Project:
         validate_certs=True,
         push_options=None,
         patchset_description=None,
-    ):
+        git_event_log: Optional[EventLog] = None,
+    ) -> None:
         """Uploads the named branch for code review."""
         if branch is None:
             branch = self.CurrentBranch
@@ -1277,14 +1321,47 @@ class Project:
             ref_spec = ref_spec + "%" + ",".join(opts)
         cmd.append(ref_spec)
 
-        GitCommand(self, cmd, bare=True, verify_command=True).Wait()
+        push_cmd = GitCommand(
+            self,
+            cmd,
+            bare=True,
+            verify_command=True,
+        )
+        push_cmd.Wait()
 
+        cls_urls = self._FindGerritUrls(push_cmd.stderr)
+
+        try:
+            rb = ReviewableBranch(self, branch, branch.LocalMerge)
+            modified_files_list = rb.modified_files
+            if git_event_log:
+                git_event_log.LogDataConfigEvents(
+                    {
+                        "cls": ",".join(cls_urls),
+                        "remote": branch.remote.name,
+                        "branch": branch.name,
+                        "files": ",".join(modified_files_list),
+                    },
+                    "repo.uploadstate",
+                )
+        except Exception as e:
+            logger.error("Tracing failed: %s", str(e))
         if not dryrun:
             msg = f"posted to {branch.remote.review} for {dest_branch}"
             self.bare_git.UpdateRef(
                 R_PUB + branch.name, R_HEADS + branch.name, message=msg
             )
 
+    @staticmethod
+    def _FindGerritUrls(stderr: Optional[str]) -> List[str]:
+        """Extracts Gerrit review URLs from git push output."""
+        if not stderr:
+            return []
+        return [
+            match.group(1)
+            for match in re.finditer(r"(https?://[^/]+/c/.+?/\+/\d+)", stderr)
+        ]
+
     @staticmethod
     def _encode_patchset_description(original):
         """Applies percent-encoding for strings sent as patchset description.
@@ -1546,11 +1623,7 @@ class Project:
 
         # If the project has been manually unshallowed (e.g. via
         # `git fetch --unshallow`), don't re-shallow it during sync.
-        if (
-            depth
-            and not is_new
-            and not os.path.exists(os.path.join(self.gitdir, "shallow"))
-        ):
+        if depth and not is_new and not self._HasShallow():
             depth = None
 
         if depth and clone_filter_for_depth:
@@ -1586,17 +1659,15 @@ class Project:
                 )
         else:
             # See if we can skip the standard network fetch entirely.
-            has_shallow = os.path.exists(os.path.join(self.gitdir, "shallow"))
+            has_shallow = self._HasShallow()
             skip_fetch = (
                 optimized_fetch
                 and IsId(self.revisionExpr)
                 and self._CheckForImmutableRevision(
-                    use_superproject=use_superproject
-                )
-                and (
-                    has_shallow
-                    or (not depth and not self._SharingProjectHasShallow())
+                    use_superproject=use_superproject,
+                    depth=depth,
                 )
+                and (has_shallow or not self._IsShallow(depth))
             )
 
             if not skip_fetch:
@@ -1678,7 +1749,9 @@ class Project:
         for linkfile in self.linkfiles:
             linkfile._Link()
 
-    def GetCommitRevisionId(self):
+    def GetCommitRevisionId(
+        self, all_refs: Optional[Dict[str, str]] = None
+    ) -> str:
         """Get revisionId of a commit.
 
         Use this method instead of GetRevisionId to get the id of the commit
@@ -1688,10 +1761,12 @@ class Project:
         if self.revisionId:
             return self.revisionId
         if not self.revisionExpr.startswith(R_TAGS):
-            return self.GetRevisionId(self._allrefs)
+            if all_refs is None:
+                all_refs = self._allrefs
+            return self.GetRevisionId(all_refs)
 
         try:
-            return self.bare_git.rev_list(self.revisionExpr, "-1")[0]
+            return self.bare_git.ResolveCommit(self.revisionExpr)
         except GitError:
             raise ManifestInvalidRevisionError(
                 f"revision {self.revisionExpr} in {self.name} not found"
@@ -1703,6 +1778,10 @@ class Project:
         Returns None if worktree is not checked out or HEAD cannot be resolved.
         """
         if self.work_git:
+            if not self.use_git_worktrees and self.bare_ref.is_loaded:
+                head = self.bare_ref.get(HEAD)
+                if head:
+                    return head
             try:
                 return self.work_git.rev_parse("HEAD")
             except GitError:
@@ -1720,7 +1799,7 @@ class Project:
             return all_refs[rev]
 
         try:
-            return self.bare_git.rev_parse("--verify", "%s^0" % rev)
+            return self.bare_git.ResolveCommit(rev)
         except GitError:
             raise ManifestInvalidRevisionError(
                 f"revision {self.revisionExpr} in {self.name} not found"
@@ -1816,8 +1895,8 @@ class Project:
             if p.Wait() != 0:
                 logger.warning("warn: %s: stateless gc failed", self.name)
 
-        head = self.work_git.GetHead()
-        if head.startswith(R_HEADS):
+        head = self._GetHead()
+        if head and head.startswith(R_HEADS):
             branch = head[len(R_HEADS) :]
             try:
                 head = all_refs[head]
@@ -2348,7 +2427,7 @@ class Project:
             # Doesn't exist
             return None
 
-        head = self.work_git.GetHead()
+        head = self._GetHead()
         if head == rev:
             # We can't destroy the branch while we are sitting
             # on it.  Switch to a detached HEAD.
@@ -2370,9 +2449,9 @@ class Project:
 
     def PruneHeads(self):
         """Prune any topic branches already merged into upstream."""
-        cb = self.CurrentBranch
         kill = []
         left = self._allrefs
+        cb = self.CurrentBranch
         for name in left.keys():
             if name.startswith(R_HEADS):
                 name = name[len(R_HEADS) :]
@@ -2384,17 +2463,25 @@ class Project:
         if not kill and not cb:
             return []
 
-        rev = self.GetRevisionId(left)
+        rev = self.GetCommitRevisionId(left)
+        head = left.get(R_HEADS + cb) if cb is not None else None
         if (
             cb is not None
-            and not self._revlist(HEAD + "..." + rev)
+            and head == rev
             and not self.IsDirty(consider_untracked=False)
         ):
             self.work_git.DetachHead(HEAD)
             kill.append(cb)
 
         if kill:
-            old = self.bare_git.GetHead()
+            if not self.use_git_worktrees:
+                old = (
+                    head
+                    if cb in kill
+                    else (self.bare_ref.head or self.bare_git.GetHead())
+                )
+            else:
+                old = self.bare_git.GetHead()
 
             try:
                 self.bare_git.DetachHead(rev)
@@ -2409,7 +2496,11 @@ class Project:
                 if IsId(old):
                     self.bare_git.DetachHead(old)
                 else:
-                    self.bare_git.SetHead(old)
+                    branch = (
+                        old[len(R_HEADS) :] if old.startswith(R_HEADS) else old
+                    )
+                    if branch not in kill:
+                        self.bare_git.SetHead(old)
                 left = self._allrefs
 
             for branch in kill:
@@ -2425,6 +2516,7 @@ class Project:
         for branch in kill:
             if R_HEADS + branch in left:
                 branch = self.GetBranch(branch)
+                branch.current = branch.name == cb
                 base = branch.LocalMerge
                 if not base:
                     base = rev
@@ -2572,6 +2664,37 @@ class Project:
             return []
         return get_submodules(self.gitdir, rev)
 
+    def GetSubmoduleRevisions(self) -> Optional[Dict[str, str]]:
+        """Read the gitlinks of our submodules at our current revision.
+
+        Discovered submodules are derived from the revision their parent was
+        at when the manifest was loaded, which is before it gets fetched.
+        Once it is up-to-date, its gitlinks have to be read again, otherwise
+        the submodules would be synced to the revisions of the previous sync.
+
+        Returns:
+            The revision of every submodule, keyed by its path inside this
+            project, or None if our revision is not available locally. A
+            revision that is merely set does not have to be fetched yet, and
+            without its objects a removed submodule cannot be told apart from
+            one that was never fetched.
+        """
+        try:
+            rev = self.GetRevisionId()
+            self.bare_git.rev_list(
+                "-1",
+                "--missing=allow-any",
+                f"{rev}^0",
+                "--",
+                log_as_error=False,
+            )
+        except (GitError, ManifestInvalidRevisionError):
+            return None
+
+        return {
+            path: sha for sha, path, _url, _shallow in self._GetSubmodules()
+        }
+
     def GetDerivedSubprojects(self):
         result = []
         if not self.Exists:
@@ -2619,6 +2742,7 @@ class Project:
                 parent=self,
                 clone_depth=clone_depth,
                 is_derived=True,
+                gitlink_path=path,
             )
             result.append(subproject)
             result.extend(subproject.GetDerivedSubprojects())
@@ -2667,18 +2791,22 @@ class Project:
         return None
 
     def _CheckForImmutableRevision(
-        self, use_superproject: Optional[bool] = None
+        self,
+        use_superproject: Optional[bool] = None,
+        depth: Optional[int] = None,
     ) -> bool:
         try:
             # if revision (sha or tag) is not present then following function
             # throws an error.
             revs = [f"{self.revisionExpr}^0"]
             upstream_rev = None
+            verify_upstream = self._ShouldVerifyUpstream(
+                use_superproject=use_superproject,
+                depth=depth,
+            )
 
-            # Only check upstream when using superproject.
-            if self.upstream and git_superproject.UseSuperproject(
-                use_superproject, self.manifest
-            ):
+            # Ensure the local upstream tracking ref also exists in the ODB.
+            if verify_upstream:
                 upstream_rev = self.GetRemote().ToLocal(self.upstream)
                 revs.append(upstream_rev)
 
@@ -2690,11 +2818,8 @@ class Project:
                 log_as_error=False,
             )
 
-            # Only verify upstream relationship for superproject scenarios
-            # without affecting plain usage.
-            if self.upstream and git_superproject.UseSuperproject(
-                use_superproject, self.manifest
-            ):
+            # Verify revision is an ancestor of the upstream tracking ref.
+            if verify_upstream:
                 self.bare_git.merge_base(
                     "--is-ancestor",
                     self.revisionExpr,
@@ -2706,6 +2831,31 @@ class Project:
             # There is no such persistent revision. We have to fetch it.
             return False
 
+    def _HasShallow(self) -> bool:
+        """Check if this project has a shallow file in its gitdir."""
+        return bool(
+            self.gitdir and os.path.exists(os.path.join(self.gitdir, "shallow"))
+        )
+
+    def _IsShallow(self, depth: Optional[int] = None) -> bool:
+        """Check if the project is shallow or sharing shallow objects."""
+        return bool(
+            self._HasShallow() or self._SharingProjectHasShallow() or depth
+        )
+
+    def _ShouldVerifyUpstream(
+        self,
+        use_superproject: Optional[bool] = None,
+        depth: Optional[int] = None,
+    ) -> bool:
+        """Whether to verify upstream ancestry during immutable revision
+        check."""
+        if not (IsId(self.revisionExpr) and self.upstream):
+            return False
+        if self._UseSuperprojectForUpstream(use_superproject):
+            return True
+        return not self._IsShallow(depth)
+
     def _SharingProjectHasShallow(self) -> bool:
         """Check if another project sharing this objdir has a "shallow" file.
 
@@ -2719,10 +2869,16 @@ class Project:
         )
         for proj in other_projects:
             if proj.objdir == self.objdir and proj.gitdir != self.gitdir:
-                if os.path.exists(os.path.join(proj.gitdir, "shallow")):
+                if proj._HasShallow():
                     return True
         return False
 
+    def _UseSuperprojectForUpstream(
+        self, use_superproject: Optional[bool] = None
+    ) -> bool:
+        """Whether to check upstream for superprojects."""
+        return git_superproject.UseSuperproject(use_superproject, self.manifest)
+
     def _FetchArchive(self, tarpath, cwd=None):
         cmd = ["archive", "-v", "-o", tarpath]
         cmd.append("--remote=%s" % self.remote.url)
@@ -2847,6 +3003,20 @@ class Project:
 
         return True
 
+    def _GetUpstreamFallback(self) -> Optional[str]:
+        """Resolve a fallback upstream branch when revisionExpr is a SHA-1.
+
+        Returns manifest default upstream or revision if it names a branch,
+        or None to fall back to fetching all heads.
+        """
+        default = self.manifest.default
+        if not default:
+            return None
+        for cand in (default.upstreamExpr, default.revisionExpr):
+            if cand and not IsId(cand) and not cand.startswith(R_TAGS):
+                return cand
+        return None
+
     def _RemoteFetch(
         self,
         name=None,
@@ -2880,31 +3050,9 @@ class Project:
             current_branch_only = True
 
         is_sha1 = IsId(self.revisionExpr)
+        upstream = self.upstream
 
         if current_branch_only:
-            if self.revisionExpr.startswith(R_TAGS):
-                # This is a tag and its commit id should never change.
-                tag_name = self.revisionExpr[len(R_TAGS) :]
-            elif self.upstream and self.upstream.startswith(R_TAGS):
-                # This is a tag and its commit id should never change.
-                tag_name = self.upstream[len(R_TAGS) :]
-
-            if is_sha1 or tag_name is not None:
-                has_shallow = os.path.exists(
-                    os.path.join(self.gitdir, "shallow")
-                )
-                if self._CheckForImmutableRevision(
-                    use_superproject=use_superproject
-                ) and (
-                    has_shallow
-                    or (not depth and not self._SharingProjectHasShallow())
-                ):
-                    if verbose:
-                        print(
-                            "Skipped fetching project %s (already have "
-                            "persistent ref)" % self.name
-                        )
-                    return True
             if is_sha1 and not depth:
                 # When syncing a specific commit and --depth is not set:
                 # * if upstream is explicitly specified and is not a sha1, fetch
@@ -2913,11 +3061,34 @@ class Project:
                 #   sync will fail.
                 # * otherwise, fetch all branches to make sure we end up with
                 #   the specific commit.
-                if self.upstream:
-                    current_branch_only = not IsId(self.upstream)
+                if not upstream:
+                    upstream = self._GetUpstreamFallback()
+
+                if upstream:
+                    current_branch_only = not IsId(upstream)
                 else:
                     current_branch_only = False
 
+            if self.revisionExpr.startswith(R_TAGS):
+                # This is a tag and its commit id should never change.
+                tag_name = self.revisionExpr[len(R_TAGS) :]
+            elif upstream and upstream.startswith(R_TAGS):
+                # This is a tag and its commit id should never change.
+                tag_name = upstream[len(R_TAGS) :]
+
+            if is_sha1 or tag_name is not None:
+                has_shallow = self._HasShallow()
+                if self._CheckForImmutableRevision(
+                    use_superproject=use_superproject,
+                    depth=depth,
+                ) and (has_shallow or not self._IsShallow(depth)):
+                    if verbose:
+                        print(
+                            "Skipped fetching project %s (already have "
+                            "persistent ref)" % self.name
+                        )
+                    return True
+
         if not name:
             name = self.remote.name
 
@@ -2976,7 +3147,7 @@ class Project:
             # have shallow objects or not. Tell git to unshallow all fetched
             # refs.  Don't do this with projects that don't have shallow
             # objects, since it is less efficient.
-            if os.path.exists(os.path.join(self.gitdir, "shallow")):
+            if self._HasShallow():
                 cmd.append("--depth=2147483647")
 
         # Use clone-depth="1" as a heuristic for repositories containing
@@ -3028,11 +3199,11 @@ class Project:
             # Shallow checkout of a specific commit, fetch from that commit and
             # not the heads only as the commit might be deeper in the history.
             spec.append(branch)
-            if self.upstream:
-                spec.append(self.upstream)
+            if upstream:
+                spec.append(upstream)
         else:
             if is_sha1:
-                branch = self.upstream
+                branch = upstream
             if branch is not None and branch.strip():
                 if not branch.startswith("refs/"):
                     branch = R_HEADS + branch
@@ -3219,7 +3390,8 @@ class Project:
             # got what we wanted, else trigger a second run of all
             # refs.
             if not self._CheckForImmutableRevision(
-                use_superproject=use_superproject
+                use_superproject=use_superproject,
+                depth=depth,
             ):
                 # Sync the current branch only with depth set to None.
                 # We always pass depth=None down to avoid infinite recursion.
@@ -4357,8 +4529,52 @@ class Project:
 
             return dotgit if subpath is None else os.path.join(dotgit, subpath)
 
+        @staticmethod
+        def _ParseHead(line: str) -> Optional[str]:
+            """Parse the content of a .git/HEAD file.
+
+            Handles both symbolic refs (e.g. 'ref: refs/heads/...') and raw
+            commit IDs (40-hex SHA-1 or 64-hex SHA-256).
+
+            Returns:
+                The ref name (e.g. 'refs/heads/main') or lowercase commit hash
+                if valid, or None if empty or invalid.
+            """
+            line = line.strip()
+            if line.startswith("ref:"):
+                ref = line[4:].strip()
+                # Ensure the ref is not empty, pure whitespace, or the
+                # "refs/heads/.invalid" placeholder used for unborn branches,
+                # empty repositories, or when the reftables backend is used
+                # (which will be the default in Git 3.0).
+                if not ref or ref == R_HEADS + ".invalid":
+                    return None
+                return ref
+            else:
+                # Normalize commit IDs to canonical lowercase hexadecimal,
+                # matching the output format of `git rev-parse`.
+                line_lower = line.lower()
+                if IsId(line_lower):
+                    return line_lower
+            return None
+
         def GetHead(self):
             """Return the ref that HEAD points to."""
+            path = None
+            try:
+                # Catch AssertionError raised by GetDotgitPath when worktree
+                # .git pointer file is malformed (e.g. missing 'gitdir:').
+                path = self.GetDotgitPath(subpath=HEAD)
+                if not platform_utils.islink(path):
+                    with open(
+                        path, "r", encoding="utf-8", errors="replace"
+                    ) as fd:
+                        ref = self._ParseHead(fd.readline())
+                    if ref:
+                        return ref
+            except (OSError, AssertionError):
+                pass
+
             try:
                 return self.symbolic_ref("-q", HEAD, log_as_error=False)
             except GitError:
@@ -4378,19 +4594,37 @@ class Project:
 
                 # Fallback to direct file reading for compatibility with broken
                 # repos, e.g. if HEAD points to an unborn branch.
-                path = self.GetDotgitPath(subpath=HEAD)
+                if not path:
+                    raise NoManifestException(
+                        self._project.RelPath(local=False), str(e)
+                    )
                 try:
-                    with open(path) as fd:
-                        line = fd.readline()
+                    with open(
+                        path, "r", encoding="utf-8", errors="replace"
+                    ) as fd:
+                        ref = self._ParseHead(fd.readline())
                 except OSError:
-                    raise NoManifestException(path, str(e))
-                try:
-                    line = line.decode()
-                except AttributeError:
-                    pass
-                if line.startswith("ref: "):
-                    return line[5:-1]
-                return line[:-1]
+                    raise NoManifestException(
+                        self._project.RelPath(local=False), str(e)
+                    )
+                if not ref:
+                    raise NoManifestException(
+                        self._project.RelPath(local=False), str(e)
+                    )
+                return ref
+
+        def ResolveCommit(self, revision: str) -> str:
+            """Resolve |revision| to a commit without option ambiguity."""
+            cmdv = ["--verify", "--quiet"]
+            if git_require((2, 30, 0)):
+                cmdv.append("--end-of-options")
+            elif revision.startswith("-"):
+                raise GitError(
+                    f"invalid revision: {revision}",
+                    project=self._project.name,
+                )
+            cmdv.append(f"{revision}^{{commit}}")
+            return self.rev_parse(*cmdv, log_as_error=False)
 
         def SetHead(self, ref, message=None):
             cmdv = []
@@ -4650,6 +4884,28 @@ class SyncBuffer:
         self._pending_failures = []
 
 
+@functools.lru_cache(maxsize=None)
+def _DefaultBranchFallback() -> str:
+    """Return the ref to use when remote default branch can't be resolved."""
+
+    def _git(args: List[str]) -> str:
+        p = GitCommand(
+            None,
+            args,
+            capture_stdout=True,
+            capture_stderr=True,
+            log_as_error=False,
+        )
+        return p.stdout.strip() if p.Wait() == 0 else ""
+
+    branch = ""
+    if git_require((2, 35, 0)):
+        branch = _git(["var", "GIT_DEFAULT_BRANCH"])
+    if not branch:
+        branch = _git(["config", "--get", "init.defaultBranch"])
+    return f"refs/heads/{branch or 'master'}"
+
+
 class MetaProject(Project):
     """A special project housed under .repo."""
 
@@ -4663,7 +4919,7 @@ class MetaProject(Project):
             worktree=worktree,
             remote=RemoteSpec("origin"),
             relpath=".repo/%s" % name,
-            revisionExpr="refs/heads/master",
+            revisionExpr=_DefaultBranchFallback(),
             revisionId=None,
             groups=None,
         )
@@ -4677,6 +4933,39 @@ class MetaProject(Project):
                     self.revisionExpr = base
                     self.revisionId = None
 
+    def _UseSuperprojectForUpstream(
+        self, use_superproject: Optional[bool] = None
+    ) -> bool:
+        # MetaProjects (the manifest repo and repo itself) never
+        # participate in a superproject relationship. Returning False
+        # here also avoids loading the manifest during `repo init`,
+        # before manifest.xml has been linked into .repo/.
+        return False
+
+    def _GetUpstreamFallback(self) -> Optional[str]:
+        # MetaProjects (the manifest repo and repo itself) do not have
+        # defaults in a manifest. Returning None here also avoids
+        # loading the manifest during `repo init`, before manifest.xml
+        # has been linked into .repo/.
+        return None
+
+    def _SharingProjectHasShallow(self) -> bool:
+        # MetaProjects (the manifest repo and repo itself) are never
+        # shared with other projects in the manifest. Returning False
+        # here also avoids loading the manifest during `repo init`,
+        # before manifest.xml has been linked into .repo/.
+        return False
+
+    def _ShouldVerifyUpstream(
+        self,
+        use_superproject: Optional[bool] = None,
+        depth: Optional[int] = None,
+    ) -> bool:
+        """MetaProjects (manifest repo and repo itself) do not verify upstream
+        ancestry.
+        """
+        return False
+
     @property
     def HasChanges(self):
         """Has the remote received new commits not yet checked out?"""
@@ -4685,8 +4974,8 @@ class MetaProject(Project):
 
         all_refs = self.bare_ref.all
         revid = self.GetRevisionId(all_refs)
-        head = self.work_git.GetHead()
-        if head.startswith(R_HEADS):
+        head = self._GetHead()
+        if head and head.startswith(R_HEADS):
             try:
                 head = all_refs[head]
             except KeyError:
@@ -4694,7 +4983,7 @@ class MetaProject(Project):
 
         if revid == head:
             return False
-        elif self._revlist(not_rev(HEAD), revid):
+        elif self._revlist("-1", not_rev(HEAD), revid):
             return True
         return False
 
@@ -5112,9 +5401,9 @@ class ManifestProject(MetaProject):
                 if is_new:
                     default_branch = self.ResolveRemoteHead()
                     if default_branch is None:
-                        # If the remote doesn't have HEAD configured, default to
-                        # master.
-                        default_branch = "refs/heads/master"
+                        # If the remote doesn't have HEAD configured, fall back
+                        # to whatever git uses as its default branch.
+                        default_branch = _DefaultBranchFallback()
                     self.revisionExpr = default_branch
                 else:
                     self.PreSync()

subcmds/abandon.py

@@ -20,7 +20,7 @@ from command import Command
 from command import DEFAULT_LOCAL_JOBS
 from error import RepoError
 from error import RepoExitError
-from git_command import git
+from git_command import IsValidBranchName
 from progress import Progress
 from repo_logging import RepoLogger
 
@@ -58,9 +58,7 @@ It is equivalent to "git branch -D <branchname>".
 
         if not opt.all:
             branches = args[0].split()
-            invalid_branches = [
-                x for x in branches if not git.check_ref_format(f"heads/{x}")
-            ]
+            invalid_branches = [x for x in branches if not IsValidBranchName(x)]
 
             if invalid_branches:
                 self.OptionParser.error(
@@ -94,7 +92,6 @@ It is equivalent to "git branch -D <branchname>".
 
     def Execute(self, opt, args):
         nb = args[0].split()
-        self.TryOverrideManifestWithSmartSync()
         err = collections.defaultdict(list)
         success = collections.defaultdict(list)
         aggregate_errors = []

subcmds/cherry_pick.py

@@ -14,6 +14,7 @@
 
 import re
 import sys
+from typing import Tuple
 
 from command import Command
 from error import GitError
@@ -43,36 +44,8 @@ change id will be added.
 
     def Execute(self, opt, args):
         reference = args[0]
-
-        p = GitCommand(
-            None,
-            ["rev-parse", "--verify", reference],
-            capture_stdout=True,
-            capture_stderr=True,
-            verify_command=True,
-        )
-        try:
-            p.Wait()
-        except GitError:
-            logger.error(p.stderr)
-            raise
-
-        sha1 = p.stdout.strip()
-
-        p = GitCommand(
-            None,
-            ["cat-file", "commit", sha1],
-            capture_stdout=True,
-            verify_command=True,
-        )
-
-        try:
-            p.Wait()
-        except GitError:
-            logger.error("error: Failed to retrieve old commit message")
-            raise
-
-        old_msg = self._StripHeader(p.stdout)
+        sha1, commit = self._ResolveReference(reference)
+        old_msg = self._StripHeader(commit)
 
         p = GitCommand(
             None,
@@ -117,6 +90,48 @@ change id will be added.
             logger.error("error: Failed to update commit message")
             raise
 
+    def _ResolveReference(self, reference: str) -> Tuple[str, str]:
+        """Resolve a commit and read it through one cat-file batch request."""
+        expression = f"{reference}^{{commit}}"
+        p = GitCommand(
+            None,
+            ["cat-file", "--batch"],
+            input=expression + "\n",
+            capture_stdout=True,
+            capture_stderr=True,
+            verify_command=True,
+        )
+        try:
+            p.Wait()
+            header, separator, output = p.stdout.partition("\n")
+            if not separator:
+                raise ValueError("missing cat-file header")
+            if header.endswith(" missing") or header.endswith(" ambiguous"):
+                raise GitError(f"commit {reference} not found")
+
+            parts = header.split(" ", 2)
+            if len(parts) != 3 or parts[1] != "commit":
+                raise ValueError(
+                    f"unexpected object type {parts[1]!r}"
+                    if len(parts) >= 2
+                    else "invalid header"
+                )
+            sha1, _object_type, _size = parts
+
+            if not output.endswith("\n"):
+                raise ValueError("truncated cat-file object")
+
+            commit = output[:-1]
+        except (GitError, ValueError) as e:
+            logger.error(
+                "error: Failed to resolve or read commit %s", reference
+            )
+            if isinstance(e, GitError):
+                raise
+            raise GitError(str(e)) from e
+
+        return sha1, commit
+
     def _IsChangeId(self, line):
         return CHANGE_ID_RE.match(line)
 

subcmds/forall.py

@@ -243,8 +243,6 @@ without iterating through the remaining projects.
 
         mirror = self.manifest.IsMirror
 
-        self.TryOverrideManifestWithSmartSync()
-
         if opt.regex:
             projects = self.FindProjects(args, all_manifests=all_trees)
         elif opt.inverse_regex:

subcmds/info.py

@@ -147,8 +147,6 @@ class Info(PagedCommand):
         if not opt.this_manifest_only:
             self.manifest = self.manifest.outer_client
 
-        self.TryOverrideManifestWithSmartSync()
-
         output_format = OutputFormat[opt.format.upper()]
         if output_format == OutputFormat.JSON:
             self._ExecuteJson(opt, args)

subcmds/init.py

@@ -33,6 +33,7 @@ _REPO_ALLOW_SHALLOW = os.environ.get("REPO_ALLOW_SHALLOW")
 
 class Init(InteractiveCommand, MirrorSafeCommand):
     COMMON = True
+    RESPECT_SMART_SYNC_OVERRIDE = False
     MULTI_MANIFEST_SUPPORT = True
     helpSummary = "Initialize a repo client checkout in the current directory"
     helpUsage = """

subcmds/overview.py

@@ -59,10 +59,15 @@ are displayed.
         for project in self.GetProjects(
             args, all_manifests=not opt.this_manifest_only
         ):
-            br = [project.GetUploadableBranch(x) for x in project.GetBranches()]
-            br = [x for x in br if x]
+            local_branches = project.GetBranches()
+            br = []
+            for name, branch in local_branches.items():
+                uploadable = project.GetUploadableBranch(name)
+                if uploadable:
+                    uploadable.branch.current = branch.current
+                    br.append(uploadable)
             if opt.current_branch:
-                br = [x for x in br if x.name == project.CurrentBranch]
+                br = [x for x in br if x.current]
             all_branches.extend(br)
 
         if not all_branches:
@@ -97,7 +102,7 @@ are displayed.
             print(
                 "%s %-33s (%2d commit%s, %s)"
                 % (
-                    branch.name == project.CurrentBranch and "*" or " ",
+                    branch.current and "*" or " ",
                     branch.name,
                     len(commits),
                     len(commits) != 1 and "s" or " ",

subcmds/prune.py

@@ -80,7 +80,7 @@ class Prune(PagedCommand):
             print(
                 "%s %-33s "
                 % (
-                    branch.name == project.CurrentBranch and "*" or " ",
+                    branch.current and "*" or " ",
                     branch.name,
                 ),
                 end="",

subcmds/rebase.py

@@ -16,7 +16,9 @@ import sys
 
 from color import Coloring
 from command import Command
+from error import GitError
 from git_command import GitCommand
+from project import Project
 from repo_logging import RepoLogger
 
 
@@ -30,6 +32,17 @@ class RebaseColoring(Coloring):
         self.fail = self.printer("fail", fg="red")
 
 
+def _ResolveOntoManifest(project: Project) -> str:
+    """Resolve project's revisionExpr to a local tracking branch.
+
+    Falls back to the raw revisionExpr if ToLocal fails or raises GitError.
+    """
+    try:
+        return project.GetRemote().ToLocal(project.revisionExpr)
+    except GitError:
+        return project.revisionExpr
+
+
 class Rebase(Command):
     COMMON = True
     helpSummary = "Rebase local branches on upstream branch"
@@ -126,6 +139,8 @@ branch but need to incorporate new upstream changes "underneath" them.
             common_args.append("--autosquash")
         if opt.interactive:
             common_args.append("-i")
+        if opt.auto_stash:
+            common_args.append("--autostash")
 
         config = self.manifest.manifestProject.config
         out = RebaseColoring(config)
@@ -162,7 +177,7 @@ branch but need to incorporate new upstream changes "underneath" them.
             args = common_args[:]
             if opt.onto_manifest:
                 args.append("--onto")
-                args.append(project.revisionExpr)
+                args.append(_ResolveOntoManifest(project))
 
             args.append(upbranch.LocalMerge)
 
@@ -175,29 +190,10 @@ branch but need to incorporate new upstream changes "underneath" them.
             out.nl()
             out.flush()
 
-            needs_stash = False
-            if opt.auto_stash:
-                stash_args = ["update-index", "--refresh", "-q"]
-
-                if GitCommand(project, stash_args).Wait() != 0:
-                    needs_stash = True
-                    # Dirty index, requires stash...
-                    stash_args = ["stash"]
-
-                    if GitCommand(project, stash_args).Wait() != 0:
-                        ret += 1
-                        continue
-
             if GitCommand(project, args).Wait() != 0:
                 ret += 1
                 continue
 
-            if needs_stash:
-                stash_args.append("pop")
-                stash_args.append("--quiet")
-                if GitCommand(project, stash_args).Wait() != 0:
-                    ret += 1
-
         if ret:
             msg_fmt = "%d projects had errors"
             self.git_event_log.ErrorEvent(msg_fmt % (ret), msg_fmt)

subcmds/start.py

@@ -18,7 +18,7 @@ from typing import NamedTuple
 from command import Command
 from command import DEFAULT_LOCAL_JOBS
 from error import RepoExitError
-from git_command import git
+from git_command import IsValidBranchName
 from git_config import IsImmutable
 from progress import Progress
 from repo_logging import RepoLogger
@@ -75,7 +75,7 @@ revision specified in the manifest.
             self.Usage()
 
         nb = args[0]
-        if not git.check_ref_format("heads/%s" % nb):
+        if not IsValidBranchName(nb):
             self.OptionParser.error("'%s' is not a valid name" % nb)
 
     @classmethod
@@ -104,7 +104,6 @@ revision specified in the manifest.
 
     def Execute(self, opt, args):
         nb = args[0]
-        self.TryOverrideManifestWithSmartSync()
         err_projects = []
         err = []
         projects = []

subcmds/sync.py

@@ -28,7 +28,7 @@ import subprocess
 import sys
 import tempfile
 import time
-from typing import List, NamedTuple, Optional, Set, Tuple, Union
+from typing import Dict, List, NamedTuple, Optional, Set, Tuple, Union
 import urllib.error
 import urllib.parse
 import urllib.request
@@ -156,6 +156,83 @@ def _SafeCheckoutOrder(checkouts: List[Project]) -> List[List[Project]]:
     return res
 
 
+def _ParentFirstBatches(projects: List[Project]) -> List[List[Project]]:
+    """Group |projects| so that a parent is fetched before its submodules.
+
+    A discovered submodule can only be fetched at the right revision once the
+    project holding its gitlink has been fetched, so it is held back to a later
+    batch than its parent. Projects that are not discovered submodules all end
+    up in the first batch, which keeps manifests without submodules on a single
+    batch.
+    """
+    batches = collections.defaultdict(list)
+    for project in projects:
+        depth = 0
+        ancestor = project
+        while ancestor.Derived and ancestor.parent:
+            depth += 1
+            ancestor = ancestor.parent
+        batches[depth].append(project)
+    return [batches[depth] for depth in sorted(batches)]
+
+
+def _RefreshDerivedRevisions(
+    projects: List[Project],
+    submodule_revisions: Optional[Dict[Project, Dict[str, str]]] = None,
+) -> List[Project]:
+    """Re-resolve the gitlinks of the discovered submodules in |projects|.
+
+    The revision of a discovered submodule is read from its parent when the
+    manifest is loaded, so it is stale as soon as the parent gets fetched. It
+    has to be resolved again once the parent is up-to-date, and before the
+    submodule itself is fetched and checked out.
+
+    Args:
+        projects: The projects whose discovered submodules to resolve.
+        submodule_revisions: Gitlinks already read, keyed by the project
+            holding them. Passing the same dict for project sets that follow
+            the same fetches, e.g. the levels of one checkout order, keeps a
+            project from being read more than once.
+
+    Returns:
+        The submodules that their parent no longer holds a gitlink for.
+    """
+    if submodule_revisions is None:
+        submodule_revisions = {}
+
+    subprojects_by_parent = collections.defaultdict(list)
+    for project in projects:
+        if project.Derived and project.parent:
+            subprojects_by_parent[project.parent].append(project)
+
+    removed = []
+    for parent, subprojects in subprojects_by_parent.items():
+        revisions = submodule_revisions.get(parent)
+        if revisions is None:
+            revisions = parent.GetSubmoduleRevisions()
+            if revisions is None:
+                # Leave the submodules of a parent we cannot read alone.
+                continue
+            submodule_revisions[parent] = revisions
+        for subproject in subprojects:
+            rev = revisions.get(subproject.gitlink_path)
+            if rev:
+                subproject.SetRevision(rev, revisionId=rev)
+            else:
+                removed.append(subproject)
+    return removed
+
+
+def _WithoutProjects(
+    projects: List[Project], unwanted: List[Project]
+) -> List[Project]:
+    """Return |projects| without the projects in |unwanted|."""
+    if not unwanted:
+        return projects
+    dropped = set(unwanted)
+    return [p for p in projects if p not in dropped]
+
+
 def _chunksize(projects: int, jobs: int) -> int:
     """Calculate chunk size for the given number of projects and jobs."""
     return min(max(1, projects // jobs), WORKER_BATCH_SIZE)
@@ -224,7 +301,8 @@ class _SyncResult(NamedTuple):
 
     Attributes:
       project_index (int): The index of the project in the shared list.
-      relpath (str): The project's relative path from the repo client top.
+      relpath (str): The project's path relative to the tree being synced.
+          Unlike Project.relpath, it is unique across submanifests.
       remote_fetched (bool): True if the remote was actually queried.
       fetch_success (bool): True if the fetch operation was successful.
       fetch_errors (List[Exception]): The Exceptions from a failed fetch.
@@ -312,6 +390,7 @@ class TeeStringIO(io.StringIO):
 
 class Sync(Command, MirrorSafeCommand):
     COMMON = True
+    RESPECT_SMART_SYNC_OVERRIDE = False
     MULTI_MANIFEST_SUPPORT = True
     helpSummary = "Update working tree to the latest revision"
     helpUsage = """
@@ -378,8 +457,12 @@ resumeable bundle file on a content delivery network. This
 may be necessary if there are problems with the local Python
 HTTP client or proxy configuration, but the Git binary works.
 
-The --fetch-submodules option enables fetching Git submodules
-of a project from server.
+The --recurse-submodules option enables syncing Git submodules of all projects
+from the server. The --no-recurse-submodules option disables syncing Git
+submodules, even when a project has sync-s="true" in the manifest.
+
+The --fetch-submodules and --no-fetch-submodules options are deprecated aliases
+for --recurse-submodules and --no-recurse-submodules, respectively.
 
 The -c/--current-branch option can be used to only fetch objects that
 are on the branch specified by a project's revision.
@@ -427,6 +510,15 @@ later is required to fix a server side protocol bug.
 
     _JOBS_WARN_THRESHOLD = 100
 
+    @staticmethod
+    def _deprecated_submodules_option(option, opt_str, _value, parser):
+        enabled = opt_str == "--fetch-submodules"
+        replacement = (
+            "--recurse-submodules" if enabled else "--no-recurse-submodules"
+        )
+        logger.warning("%s is deprecated; use %s instead", opt_str, replacement)
+        setattr(parser.values, option.dest, enabled)
+
     def _Options(self, p, show_smart=True):
         p.add_option(
             "--jobs-network",
@@ -545,6 +637,13 @@ later is required to fix a server side protocol bug.
             help="temporary manifest to use for this sync",
             metavar="NAME.xml",
         )
+        p.add_option(
+            "-g",
+            "--groups",
+            help="sync projects matching the specific groups.  Not persistent "
+            "unlike when used on init",
+            metavar="GROUP",
+        )
         p.add_option(
             "--clone-bundle",
             action="store_true",
@@ -569,9 +668,29 @@ later is required to fix a server side protocol bug.
             help="password to authenticate with the manifest server",
         )
         p.add_option(
-            "--fetch-submodules",
+            "--recurse-submodules",
             action="store_true",
-            help="fetch submodules from server",
+            help="sync submodules from server",
+        )
+        p.add_option(
+            "--no-recurse-submodules",
+            dest="recurse_submodules",
+            action="store_false",
+            help="don't sync submodules from server",
+        )
+        p.add_option(
+            "--fetch-submodules",
+            dest="recurse_submodules",
+            action="callback",
+            callback=self._deprecated_submodules_option,
+            help=optparse.SUPPRESS_HELP,
+        )
+        p.add_option(
+            "--no-fetch-submodules",
+            dest="recurse_submodules",
+            action="callback",
+            callback=self._deprecated_submodules_option,
+            help=optparse.SUPPRESS_HELP,
         )
         p.add_option(
             "--use-superproject",
@@ -741,8 +860,9 @@ later is required to fix a server side protocol bug.
 
         all_projects = self.GetProjects(
             args,
+            groups=opt.groups,
             missing_ok=True,
-            submodules_ok=opt.fetch_submodules,
+            submodules_ok=opt.recurse_submodules,
             manifest=manifest,
             all_manifests=not opt.this_manifest_only,
         )
@@ -1025,6 +1145,40 @@ later is required to fix a server side protocol bug.
 
         return _FetchResult(ret, fetched)
 
+    def _FetchParentFirst(
+        self,
+        projects: List[Project],
+        opt: optparse.Values,
+        err_event: _threading.Event,
+        ssh_proxy: ssh.ProxyManager,
+        errors: List[Exception],
+    ) -> _FetchResult:
+        """Fetch |projects|, holding submodules back until their parent is done.
+
+        Args:
+            projects: Projects to fetch.
+            opt: Program options returned from optparse. See _Options().
+            err_event: Whether an error was hit while processing.
+            ssh_proxy: SSH manager for clients & masters.
+            errors: A list to accumulate errors.
+
+        Returns:
+            _FetchResult for all the batches combined.
+        """
+        success = True
+        fetched = set()
+        for batch in _ParentFirstBatches(projects):
+            batch = _WithoutProjects(batch, _RefreshDerivedRevisions(batch))
+            if not batch:
+                continue
+            batch.sort(key=self._fetch_times.Get, reverse=True)
+            result = self._Fetch(batch, opt, err_event, ssh_proxy, errors)
+            success = success and result.success
+            fetched.update(result.projects)
+            if not success and opt.fail_fast:
+                break
+        return _FetchResult(success, fetched)
+
     def _FetchMain(
         self, opt, args, all_projects, err_event, ssh_proxy, manifest, errors
     ):
@@ -1041,12 +1195,10 @@ later is required to fix a server side protocol bug.
         Returns:
             List of all projects that should be checked out.
         """
-        to_fetch = []
-        to_fetch.extend(all_projects)
-        to_fetch.sort(key=self._fetch_times.Get, reverse=True)
-
         try:
-            result = self._Fetch(to_fetch, opt, err_event, ssh_proxy, errors)
+            result = self._FetchParentFirst(
+                all_projects, opt, err_event, ssh_proxy, errors
+            )
             success = result.success
             fetched = result.projects
             if not success:
@@ -1070,8 +1222,9 @@ later is required to fix a server side protocol bug.
                 self._ReloadManifest(None, manifest)
                 all_projects = self.GetProjects(
                     args,
+                    groups=opt.groups,
                     missing_ok=True,
-                    submodules_ok=opt.fetch_submodules,
+                    submodules_ok=opt.recurse_submodules,
                     manifest=manifest,
                     all_manifests=not opt.this_manifest_only,
                 )
@@ -1088,7 +1241,9 @@ later is required to fix a server side protocol bug.
                 if previously_missing_set == missing_set:
                     break
                 previously_missing_set = missing_set
-                result = self._Fetch(missing, opt, err_event, ssh_proxy, errors)
+                result = self._FetchParentFirst(
+                    missing, opt, err_event, ssh_proxy, errors
+                )
                 success = result.success
                 new_fetched = result.projects
                 if not success:
@@ -2317,8 +2472,9 @@ later is required to fix a server side protocol bug.
 
         all_projects = self.GetProjects(
             args,
+            groups=opt.groups,
             missing_ok=True,
-            submodules_ok=opt.fetch_submodules,
+            submodules_ok=opt.recurse_submodules,
             manifest=manifest,
             all_manifests=not opt.this_manifest_only,
         )
@@ -2714,7 +2870,7 @@ later is required to fix a server side protocol bug.
 
         return _SyncResult(
             project_index=project_index,
-            relpath=project.relpath,
+            relpath=project.RelPath(local=opt.this_manifest_only),
             fetch_success=fetch_success,
             remote_fetched=remote_fetched,
             checkout_success=checkout_success,
@@ -2862,6 +3018,10 @@ later is required to fix a server side protocol bug.
         self._interleaved_err_checkout = False
         self._interleaved_err_checkout_results = []
 
+        # Project.relpath is relative to its own (sub)manifest, so it does not
+        # tell apart projects of different manifests being synced together.
+        _RelPath = lambda p: p.RelPath(local=opt.this_manifest_only)
+
         err_event = multiprocessing.Event()
         finished_relpaths = set()
         project_list = list(all_projects)
@@ -2898,13 +3058,13 @@ later is required to fix a server side protocol bug.
                             projects_to_sync = [
                                 p
                                 for p in project_list
-                                if p.relpath not in finished_relpaths
+                                if _RelPath(p) not in finished_relpaths
                             ]
                             if not projects_to_sync:
                                 break
 
                             pending_relpaths = {
-                                p.relpath for p in projects_to_sync
+                                _RelPath(p) for p in projects_to_sync
                             }
                             if previously_pending_relpaths == pending_relpaths:
                                 stalled_projects_str = "\n".join(
@@ -2933,12 +3093,22 @@ later is required to fix a server side protocol bug.
                             # projects in one level can be processed in
                             # parallel, but we must wait for a level to complete
                             # before starting the next.
+                            submodule_revisions = {}
                             for level_projects in _SafeCheckoutOrder(
                                 projects_to_sync
                             ):
                                 if not level_projects:
                                     continue
 
+                                level_projects = _WithoutProjects(
+                                    level_projects,
+                                    _RefreshDerivedRevisions(
+                                        level_projects, submodule_revisions
+                                    ),
+                                )
+                                if not level_projects:
+                                    continue
+
                                 objdir_project_map = collections.defaultdict(
                                     list
                                 )
@@ -2980,8 +3150,9 @@ later is required to fix a server side protocol bug.
                             self._ReloadManifest(None, manifest)
                             project_list = self.GetProjects(
                                 args,
+                                groups=opt.groups,
                                 missing_ok=True,
-                                submodules_ok=opt.fetch_submodules,
+                                submodules_ok=opt.recurse_submodules,
                                 manifest=manifest,
                                 all_manifests=not opt.this_manifest_only,
                             )

subcmds/upload.py

@@ -25,7 +25,6 @@ from editor import Editor
 from error import GitError
 from error import SilentRepoExitError
 from error import UploadError
-from git_command import GitCommand
 from git_refs import R_HEADS
 import git_superproject
 from hooks import RepoHook
@@ -379,7 +378,7 @@ Gerrit Code Review:  https://www.gerritcodereview.com/
             default=True,
             help="disable verifying ssl certs (unsafe)",
         )
-        RepoHook.AddOptionGroup(p, "pre-upload")
+        RepoHook.AddOptionGroup(p, "pre-upload", allow_fix=True)
 
     def _SingleBranch(self, opt, branch, people):
         project = branch.project
@@ -649,6 +648,7 @@ Gerrit Code Review:  https://www.gerritcodereview.com/
             validate_certs=opt.validate_certs,
             push_options=push_options,
             patchset_description=opt.patchset_description,
+            git_event_log=self.git_event_log,
         )
 
         branch.uploaded = True
@@ -704,36 +704,31 @@ Gerrit Code Review:  https://www.gerritcodereview.com/
             raise UploadExitError(aggregate_errors=aggregate_errors)
 
     def _GetMergeBranch(self, project, local_branch=None):
+        """Get the merge branch name for a local branch.
+
+        Resolves the merge branch in-memory via project configuration to
+        avoid git subprocess overhead during upload.
+        """
         if local_branch is None:
-            p = GitCommand(
-                project,
-                ["rev-parse", "--abbrev-ref", "HEAD"],
-                capture_stdout=True,
-                capture_stderr=True,
-            )
-            p.Wait()
-            local_branch = p.stdout.strip()
-        p = GitCommand(
-            project,
-            ["config", "--get", "branch.%s.merge" % local_branch],
-            capture_stdout=True,
-            capture_stderr=True,
-        )
-        p.Wait()
-        merge_branch = p.stdout.strip()
-        return merge_branch
+            local_branch = project.CurrentBranch
+        if local_branch:
+            branch = project.GetBranch(local_branch)
+            if branch.merge:
+                return branch.merge
+        return ""
 
     @classmethod
     def _GatherOne(cls, opt, project_idx):
         """Figure out the upload status for |project|."""
         project = cls.get_parallel_context()["projects"][project_idx]
+        cbr = None
         if opt.current_branch:
             cbr = project.CurrentBranch
             up_branch = project.GetUploadableBranch(cbr)
             avail = [up_branch] if up_branch else None
         else:
             avail = project.GetUploadableBranches(opt.branch)
-        return (project_idx, avail)
+        return (project_idx, avail, cbr)
 
     def Execute(self, opt, args):
         projects = self.GetProjects(
@@ -743,7 +738,7 @@ Gerrit Code Review:  https://www.gerritcodereview.com/
         def _ProcessResults(_pool, _out, results):
             pending = []
             for result in results:
-                project_idx, avail = result
+                project_idx, avail, current_branch = result
                 project = projects[project_idx]
                 if avail is None:
                     logger.error(
@@ -751,7 +746,7 @@ Gerrit Code Review:  https://www.gerritcodereview.com/
                         "You might be able to fix the branch by running:\n"
                         "  git branch --set-upstream-to m/%s",
                         project.RelPath(local=opt.this_manifest_only),
-                        project.CurrentBranch,
+                        current_branch,
                         project.manifest.branch,
                     )
                 elif avail:

subcmds/version.py

@@ -14,10 +14,12 @@
 
 import platform
 import sys
+from typing import Any, Tuple
 
 from command import Command
 from command import MirrorSafeCommand
 from git_command import git
+from git_command import git_require
 from git_command import RepoSourceVersion
 from git_command import user_agent
 from git_refs import HEAD
@@ -34,6 +36,22 @@ class Version(Command, MirrorSafeCommand):
 %prog
 """
 
+    @staticmethod
+    def _RepoVersion(project: Any) -> Tuple[str, str]:
+        """Return repo's describe string and commit date."""
+        if git_require((2, 32, 0)):
+            output = project.bare_git.log(
+                "-1", "--format=%(describe)%n%cD", HEAD
+            )
+            description, commit_date = output.rstrip("\n").split("\n", 1)
+            if description:
+                return description, commit_date
+
+        return (
+            project.bare_git.describe(HEAD),
+            project.bare_git.log("-1", "--format=%cD", HEAD),
+        )
+
     def Execute(self, opt, args):
         rp = self.manifest.repoProject
         rem = rp.GetRemote()
@@ -41,11 +59,11 @@ class Version(Command, MirrorSafeCommand):
 
         # These might not be the same.  Report them both.
         src_ver = RepoSourceVersion()
-        rp_ver = rp.bare_git.describe(HEAD)
+        rp_ver, commit_date = self._RepoVersion(rp)
         print(f"repo version {rp_ver}")
         print(f"       (from {rem.url})")
         print(f"       (tracking {branch.merge})")
-        print(f"       ({rp.bare_git.log('-1', '--format=%cD', HEAD)})")
+        print(f"       ({commit_date})")
 
         if self.wrapper_path is not None:
             print(f"repo launcher version {self.wrapper_version}")

tests/test_command.py

@@ -14,6 +14,8 @@
 
 """Unittests for the command.py module."""
 
+import pytest
+
 from command import Command
 
 
@@ -86,3 +88,32 @@ def test_get_projects_keeps_derived_subprojects_for_repeated_repo():
     projects = cmd.GetProjects([])
 
     assert set(projects) == {project_a, project_b, submodule_a, submodule_b}
+
+
+@pytest.mark.parametrize(
+    "submodules_ok, sync_s, includes_submodule",
+    [
+        (None, False, False),
+        (None, True, True),
+        (True, False, True),
+        (True, True, True),
+        (False, False, False),
+        (False, True, False),
+    ],
+)
+def test_get_projects_submodule_override(
+    submodules_ok, sync_s, includes_submodule
+):
+    """The CLI override takes precedence over a project's sync-s setting."""
+    submodule = FakeProject("submodule", "project/submodule")
+    project = FakeProject(
+        "project",
+        "project",
+        derived_subprojects=[submodule],
+        sync_s=sync_s,
+    )
+    cmd = Command(manifest=FakeManifest([project]))
+
+    projects = cmd.GetProjects([], submodules_ok=submodules_ok)
+
+    assert (submodule in projects) is includes_submodule

tests/test_git_command.py

@@ -231,6 +231,24 @@ class GitCommandStreamLogsTest(unittest.TestCase):
 class GitCallUnitTest(unittest.TestCase):
     """Tests the _GitCall class (via git_command.git)."""
 
+    def test_valid_branch_name_uses_branch_mode(self) -> None:
+        """Branch validation applies Git's branch-specific restrictions."""
+        command = mock.MagicMock()
+        command.Wait.return_value = 1
+        with mock.patch.object(
+            git_command, "GitCommand", return_value=command
+        ) as check:
+            self.assertFalse(git_command.IsValidBranchName("-topic"))
+
+        check.assert_called_once_with(
+            None,
+            ["check-ref-format", "--branch", "-topic"],
+            capture_stdout=True,
+            capture_stderr=True,
+            add_event_log=False,
+            log_as_error=False,
+        )
+
     def test_version_tuple(self):
         """Check git.version_tuple() handling."""
         ver = git_command.git.version_tuple()

tests/test_git_config.py

@@ -256,8 +256,8 @@ def test_remote_save_with_push_url_without_projectname(
         ("0" * 64, True),
         ("f" * 64, True),
         ("a" * 39, False),
-        ("a" * 41, True),
-        ("a" * 63, True),
+        ("a" * 41, False),
+        ("a" * 63, False),
         ("a" * 65, False),
         ("g" * 40, False),
         ("g" * 64, False),

tests/test_git_refs.py

@@ -17,6 +17,8 @@
 import os
 from pathlib import Path
 import subprocess
+from typing import Any, List
+from unittest import mock
 
 import pytest
 import utils_for_test
@@ -24,7 +26,7 @@ import utils_for_test
 import git_refs
 
 
-def _run(repo, *args):
+def _run(repo: str, *args: str) -> str:
     return subprocess.run(
         ["git", "-C", repo, *args],
         stdout=subprocess.PIPE,
@@ -34,7 +36,7 @@ def _run(repo, *args):
     ).stdout.strip()
 
 
-def _init_repo(tmp_path, reftable=False):
+def _init_repo(tmp_path: Path, reftable: bool = False) -> str:
     repo = os.path.join(tmp_path, "repo")
     ref_format = "reftable" if reftable else "files"
     utils_for_test.init_git_tree(repo, ref_format=ref_format)
@@ -57,10 +59,154 @@ def test_reads_refs(tmp_path, reftable):
     branch = _run(repo, "symbolic-ref", "--short", "HEAD")
     head = _run(repo, "rev-parse", "HEAD")
     assert refs.symref("HEAD") == f"refs/heads/{branch}"
+    assert refs.head == f"refs/heads/{branch}"
     assert refs.get("HEAD") == head
     assert refs.get(f"refs/heads/{branch}") == head
 
 
+@pytest.mark.parametrize("reftable", [False, True])
+def test_reads_detached_head(tmp_path: Path, reftable: bool) -> None:
+    if reftable and not utils_for_test.supports_reftable():
+        pytest.skip("reftable not supported")
+
+    repo = _init_repo(tmp_path, reftable=reftable)
+    head = _run(repo, "rev-parse", "HEAD")
+    _run(repo, "checkout", "--detach", head)
+    refs = git_refs.GitRefs(os.path.join(repo, ".git"))
+
+    assert refs.symref("HEAD") == ""
+    assert refs.head == head
+    assert refs.get("HEAD") == head
+
+
+def test_reads_head_with_root_refs_in_one_command(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Git 2.45 and newer include HEAD in the ref snapshot."""
+    head = "1" * 40
+    commands = []
+
+    class FakeGitCommand:
+        def __init__(
+            self, _project: Any, cmdv: List[str], **_kwargs: Any
+        ) -> None:
+            commands.append(cmdv)
+            self.stdout = (
+                f"{head}\0HEAD\0refs/heads/main\n"
+                f"{head}\0refs/heads/main\0\n"
+            )
+
+        def Wait(self) -> int:
+            return 0
+
+    monkeypatch.setattr(git_refs, "GitCommand", FakeGitCommand)
+    monkeypatch.setattr(git_refs, "git_require", lambda _version: True)
+    refs = git_refs.GitRefs("/nonexistent")
+    with mock.patch.object(refs, "_ReadSymbolicRef") as read_head:
+        assert refs.get("HEAD") == head
+
+    assert commands == [
+        [
+            "for-each-ref",
+            "--include-root-refs",
+            "--format=%(objectname)%00%(refname)%00%(symref)",
+            "HEAD",
+            "refs",
+        ]
+    ]
+    read_head.assert_not_called()
+
+
+def test_root_ref_snapshot_falls_back_for_unborn_head(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """An unborn HEAD still uses symbolic-ref after the ref snapshot."""
+
+    class FakeGitCommand:
+        def __init__(
+            self, _project: Any, _cmdv: List[str], **_kwargs: Any
+        ) -> None:
+            self.stdout = ""
+
+        def Wait(self) -> int:
+            return 0
+
+    monkeypatch.setattr(git_refs, "GitCommand", FakeGitCommand)
+    monkeypatch.setattr(git_refs, "git_require", lambda _version: True)
+    refs = git_refs.GitRefs("/nonexistent")
+
+    def read_head(name: str) -> None:
+        assert name == "HEAD"
+        refs._symref[name] = "refs/heads/main"
+
+    monkeypatch.setattr(refs, "_ReadSymbolicRef", read_head)
+
+    assert refs.symref("HEAD") == "refs/heads/main"
+
+
+def test_old_git_keeps_separate_head_fallback(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Git before 2.45 uses the original for-each-ref and HEAD calls."""
+    head = "1" * 40
+    commands = []
+
+    class FakeGitCommand:
+        def __init__(
+            self, _project: Any, cmdv: List[str], **_kwargs: Any
+        ) -> None:
+            commands.append(cmdv)
+            self.stdout = f"{head}\0refs/heads/main\0\n"
+
+        def Wait(self) -> int:
+            return 0
+
+    monkeypatch.setattr(git_refs, "GitCommand", FakeGitCommand)
+    monkeypatch.setattr(git_refs, "git_require", lambda _version: False)
+    refs = git_refs.GitRefs("/nonexistent")
+
+    def read_head(name: str) -> None:
+        assert name == "HEAD"
+        refs._symref[name] = "refs/heads/main"
+
+    monkeypatch.setattr(refs, "_ReadSymbolicRef", read_head)
+
+    assert refs.get("HEAD") == head
+    assert commands == [
+        [
+            "for-each-ref",
+            "--format=%(objectname)%00%(refname)%00%(symref)",
+        ]
+    ]
+
+
+def test_for_each_ref_failure_falls_back_to_symbolic_ref(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """When for-each-ref fails, HEAD is still resolved via symbolic-ref."""
+
+    class FakeGitCommand:
+        def __init__(
+            self, _project: Any, _cmdv: List[str], **_kwargs: Any
+        ) -> None:
+            self.stdout = ""
+
+        def Wait(self) -> int:
+            return 1
+
+    monkeypatch.setattr(git_refs, "GitCommand", FakeGitCommand)
+    monkeypatch.setattr(git_refs, "git_require", lambda _version: True)
+    refs = git_refs.GitRefs("/nonexistent")
+
+    def read_head(name: str) -> None:
+        assert name == "HEAD"
+        refs._symref[name] = "refs/heads/main"
+
+    monkeypatch.setattr(refs, "_ReadSymbolicRef", read_head)
+
+    assert refs.symref("HEAD") == "refs/heads/main"
+
+
 @pytest.mark.parametrize("reftable", [False, True])
 def test_updates_when_refs_change(tmp_path, reftable):
     if reftable and not utils_for_test.supports_reftable():

tests/test_git_superproject.py

@@ -542,14 +542,15 @@ class SuperprojectTestCase(unittest.TestCase):
             with mock.patch(
                 "git_superproject.GitCommand", autospec=True
             ) as mock_git_command:
-                with mock.patch(
-                    "git_superproject.GitRefs.get", autospec=True
-                ) as mock_git_refs:
+                with mock.patch.object(
+                    self._superproject, "_GetRef"
+                ) as get_ref:
                     instance = mock_git_command.return_value
                     instance.Wait.return_value = 0
-                    mock_git_refs.side_effect = ["", "1234"]
+                    get_ref.side_effect = ["", "1234"]
 
                     self.assertTrue(self._superproject._Fetch())
+                    get_ref.assert_called_with("refs/heads/main")
                     self.assertEqual(
                         # TODO: Once we require Python 3.8+,
                         #  use 'mock_git_command.call_args.args'.
@@ -572,6 +573,7 @@ class SuperprojectTestCase(unittest.TestCase):
 
                     # If branch for revision exists, set as --negotiation-tip.
                     self.assertTrue(self._superproject._Fetch())
+                    get_ref.assert_called_with("refs/heads/main")
                     self.assertEqual(
                         # TODO: Once we require Python 3.8+,
                         #  use 'mock_git_command.call_args.args'.
@@ -593,3 +595,21 @@ class SuperprojectTestCase(unittest.TestCase):
                             ],
                         ),
                     )
+
+    def test_GetRef_resolves_only_the_requested_ref(self) -> None:
+        command = mock.MagicMock(stdout="1234\n")
+        command.Wait.return_value = 0
+        with mock.patch(
+            "git_superproject.GitCommand", return_value=command
+        ) as git_command:
+            self.assertEqual("1234", self._superproject._GetRef("HEAD"))
+
+        git_command.assert_called_once_with(
+            None,
+            ["rev-parse", "--verify", "--quiet", "HEAD"],
+            gitdir=self._superproject._work_git,
+            bare=True,
+            capture_stdout=True,
+            capture_stderr=True,
+            log_as_error=False,
+        )

tests/test_hooks.py

@@ -15,6 +15,7 @@
 """Unittests for the hooks.py module."""
 
 from io import StringIO
+from pathlib import Path
 import sys
 
 import pytest
@@ -105,3 +106,98 @@ def test_post_sync_argument_validation() -> None:
 
     finally:
         sys.stderr = old_stderr
+
+
+@pytest.mark.parametrize("yes_val", (True, False))
+def test_repo_upload_yes_arg(tmp_path: Path, yes_val: bool) -> None:
+    """Test that yes is passed in kwargs during hook execution."""
+
+    class FakeProject:
+        def __init__(self, worktree: str) -> None:
+            self.worktree = worktree
+            self.enabled_repo_hooks = ["pre-upload"]
+            self.config = None
+
+    hook_file = tmp_path / "pre-upload.py"
+
+    hook_content = """
+def main(project_list, **kwargs):
+    project_list.append(kwargs.get("yes"))
+"""
+    hook_file.write_text(hook_content)
+
+    hook = hooks.RepoHook(
+        hook_type="pre-upload",
+        hooks_project=FakeProject(str(tmp_path)),
+        repo_topdir=str(tmp_path),
+        manifest_url="https://gerrit",
+        allow_all_hooks=True,
+        yes=yes_val,
+    )
+
+    project_list = []
+    res = hook.Run(project_list=project_list, worktree_list=[])
+
+    assert res is True
+    assert project_list == [yes_val]
+
+
+@pytest.mark.parametrize("fix_val", (True, False))
+def test_repo_upload_fix_arg(tmp_path: Path, fix_val: bool) -> None:
+    """Test that fix is passed in kwargs during hook execution."""
+
+    class FakeProject:
+        def __init__(self, worktree: str) -> None:
+            self.worktree = worktree
+            self.enabled_repo_hooks = ["pre-upload"]
+            self.config = None
+
+    hook_file = tmp_path / "pre-upload.py"
+
+    hook_content = """
+def main(project_list, **kwargs):
+    project_list.append(kwargs.get("fix"))
+"""
+    hook_file.write_text(hook_content)
+
+    hook = hooks.RepoHook(
+        hook_type="pre-upload",
+        hooks_project=FakeProject(str(tmp_path)),
+        repo_topdir=str(tmp_path),
+        manifest_url="https://gerrit",
+        allow_all_hooks=True,
+        fix=fix_val,
+    )
+
+    project_list = []
+    res = hook.Run(project_list=project_list, worktree_list=[])
+
+    assert res is True
+    assert project_list == [fix_val]
+
+
+def test_from_subcmd_without_fix_option() -> None:
+    """Test that FromSubcmd works when opt does not have fix attribute."""
+
+    class Remote:
+        url = "https://gerrit"
+
+    class FakeManifest:
+        repo_hooks_project = None
+        topdir = "/fake/topdir"
+
+        class manifestProject:
+            @staticmethod
+            def GetRemote(name: str) -> "Remote":
+                return Remote()
+
+        class contactinfo:
+            bugurl = "https://bugs"
+
+    class FakeOpt:
+        bypass_hooks = False
+        allow_all_hooks = False
+        ignore_hooks = False
+
+    hook = hooks.RepoHook.FromSubcmd(FakeManifest(), FakeOpt(), "post-sync")
+    assert hook._fix is False

tests/test_subcmds_cherry_pick.py

@@ -0,0 +1,85 @@
+# Copyright (C) 2026 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Unittests for subcmds/cherry_pick.py."""
+
+from unittest import mock
+
+import pytest
+
+from error import GitError
+from git_command import GitCommand
+from subcmds import cherry_pick
+
+
+def test_resolve_reference_uses_one_typed_batch_request(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    oid = "1" * 40
+    commit = "tree " + "2" * 40 + "\n\nSubject 🚀\n\nBody\n"
+    output = oid + " commit " + str(len(commit.encode("utf-8"))) + "\n"
+    output += commit + "\n"
+    command = mock.create_autospec(GitCommand, instance=True)
+    command.stdout = output
+    command.stderr = ""
+    command.Wait.return_value = 0
+    run_git = mock.create_autospec(GitCommand, return_value=command)
+    monkeypatch.setattr(cherry_pick, "GitCommand", run_git)
+
+    resolved, contents = cherry_pick.CherryPick()._ResolveReference("topic")
+
+    assert resolved == oid
+    assert contents == commit
+    run_git.assert_called_once_with(
+        None,
+        ["cat-file", "--batch"],
+        input="topic^{commit}\n",
+        capture_stdout=True,
+        capture_stderr=True,
+        verify_command=True,
+    )
+
+
+def test_resolve_reference_rejects_missing_object(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    command = mock.create_autospec(GitCommand, instance=True)
+    command.stdout = "topic^{commit} missing\n"
+    command.stderr = ""
+    command.Wait.return_value = 0
+    monkeypatch.setattr(
+        cherry_pick,
+        "GitCommand",
+        mock.create_autospec(GitCommand, return_value=command),
+    )
+
+    with pytest.raises(GitError, match="commit topic not found"):
+        cherry_pick.CherryPick()._ResolveReference("topic")
+
+
+def test_resolve_reference_rejects_ambiguous_object(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    command = mock.create_autospec(GitCommand, instance=True)
+    command.stdout = "topic^{commit} ambiguous\n"
+    command.stderr = ""
+    command.Wait.return_value = 0
+    monkeypatch.setattr(
+        cherry_pick,
+        "GitCommand",
+        mock.create_autospec(GitCommand, return_value=command),
+    )
+
+    with pytest.raises(GitError, match="commit topic not found"):
+        cherry_pick.CherryPick()._ResolveReference("topic")

tests/test_subcmds_gc.py

@@ -24,7 +24,7 @@ class GcCommand(unittest.TestCase):
     """Tests for gc command."""
 
     def setUp(self):
-        self.cmd = gc.Gc()
+        self.cmd = gc.Gc(manifest=mock.MagicMock())
         self.opt, self.args = self.cmd.OptionParser.parse_args([])
         self.opt.this_manifest_only = False
         self.opt.repack = False

tests/test_subcmds_rebase.py

@@ -0,0 +1,91 @@
+# Copyright (C) 2026 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Unittests for the subcmds/rebase.py module."""
+
+import contextlib
+import io
+from types import SimpleNamespace
+from unittest import mock
+
+from error import GitError
+from subcmds import rebase
+
+
+def test_resolve_onto_manifest_success() -> None:
+    """Test _ResolveOntoManifest when ToLocal succeeds."""
+    project = mock.MagicMock()
+    project.revisionExpr = "main"
+
+    remote = mock.MagicMock()
+    remote.ToLocal.return_value = "refs/remotes/goog/main"
+    project.GetRemote.return_value = remote
+
+    res = rebase._ResolveOntoManifest(project)
+    assert res == "refs/remotes/goog/main"
+    project.GetRemote.assert_called_once()
+    remote.ToLocal.assert_called_once_with("main")
+
+
+def test_resolve_onto_manifest_fallback() -> None:
+    """Test _ResolveOntoManifest when ToLocal raises GitError."""
+    project = mock.MagicMock()
+    project.revisionExpr = "main"
+
+    remote = mock.MagicMock()
+    remote.ToLocal.side_effect = GitError("Failed to resolve")
+    project.GetRemote.return_value = remote
+
+    res = rebase._ResolveOntoManifest(project)
+    assert res == "main"
+    project.GetRemote.assert_called_once()
+    remote.ToLocal.assert_called_once_with("main")
+
+
+def test_execute_delegates_autostash_to_rebase() -> None:
+    """--auto-stash is one rebase process, including staged-only changes."""
+    cmd = rebase.Rebase()
+    cmd.manifest = mock.MagicMock()
+    cmd.git_event_log = mock.MagicMock()
+    project = mock.MagicMock()
+    project.CurrentBranch = "topic"
+    project.RelPath.return_value = "project"
+    branch = mock.MagicMock()
+    branch.LocalMerge = "refs/remotes/origin/main"
+    project.GetBranch.return_value = branch
+    cmd.GetProjects = mock.MagicMock(return_value=[project])
+    opt = SimpleNamespace(
+        interactive=False,
+        fail_fast=False,
+        whitespace=None,
+        quiet=False,
+        force_rebase=False,
+        ff=True,
+        autosquash=False,
+        auto_stash=True,
+        onto_manifest=False,
+        this_manifest_only=False,
+    )
+    git_command = mock.MagicMock()
+    git_command.Wait.return_value = 0
+
+    with mock.patch.object(
+        rebase, "GitCommand", return_value=git_command
+    ) as run_git, contextlib.redirect_stdout(io.StringIO()):
+        assert cmd.Execute(opt, []) == 0
+
+    run_git.assert_called_once_with(
+        project,
+        ["rebase", "--autostash", "refs/remotes/origin/main"],
+    )

tests/test_subcmds_sync.py

@@ -14,10 +14,13 @@
 """Unittests for the subcmds/sync.py module."""
 
 import json
+import optparse
 import os
+from pathlib import Path
 import shutil
 import tempfile
 import time
+from typing import Dict, List, Optional
 import unittest
 from unittest import mock
 
@@ -26,10 +29,51 @@ import pytest
 import command
 from error import GitError
 from error import RepoExitError
+import manifest_xml
 from project import SyncNetworkHalfResult
 from subcmds import sync
 
 
+@pytest.mark.parametrize(
+    "cli_args, expected",
+    [
+        ([], None),
+        (["--recurse-submodules"], True),
+        (["--no-recurse-submodules"], False),
+        (["--fetch-submodules"], True),
+        (["--no-fetch-submodules"], False),
+    ],
+)
+def test_recurse_submodules_option(cli_args, expected):
+    """The submodule flags preserve an unset manifest-driven state."""
+    cmd = sync.Sync()
+
+    opts, _ = cmd.OptionParser.parse_args(cli_args)
+
+    assert opts.recurse_submodules is expected
+
+
+@pytest.mark.parametrize(
+    "old_flag, new_flag",
+    [
+        ("--fetch-submodules", "--recurse-submodules"),
+        ("--no-fetch-submodules", "--no-recurse-submodules"),
+    ],
+)
+def test_recurse_submodules_option_deprecation(old_flag, new_flag):
+    """The old submodule flags warn and direct users to their replacements."""
+    cmd = sync.Sync()
+
+    with mock.patch.object(sync.logger, "warning") as warning:
+        cmd.OptionParser.parse_args([old_flag])
+
+    warning.assert_called_once_with(
+        "%s is deprecated; use %s instead", old_flag, new_flag
+    )
+
+    assert old_flag not in cmd.OptionParser.format_help()
+
+
 @pytest.mark.parametrize(
     "use_superproject, cli_args, result",
     [
@@ -56,6 +100,120 @@ def test_get_current_branch_only(use_superproject, cli_args, result):
         assert cmd._GetCurrentBranchOnly(opts, cmd.manifest) == result
 
 
+@pytest.mark.parametrize(
+    "cli_args, expected_groups",
+    [
+        ([], None),
+        (["-g", "groupA"], "groupA"),
+        (["--groups=groupB,groupC"], "groupB,groupC"),
+    ],
+)
+def test_groups_option_parsing(cli_args, expected_groups):
+    """Test --groups / -g option parsing."""
+    cmd = sync.Sync()
+    opts, _ = cmd.OptionParser.parse_args(cli_args)
+    assert opts.groups == expected_groups
+
+
+def _create_manifest_with_groups(topdir: Path) -> manifest_xml.XmlManifest:
+    """Create a test XmlManifest with projects assigned to various groups."""
+    repodir = topdir / ".repo"
+    manifest_dir = repodir / "manifests"
+    manifest_file = repodir / manifest_xml.MANIFEST_FILE_NAME
+
+    repodir.mkdir(exist_ok=True)
+    manifest_dir.mkdir(exist_ok=True)
+
+    gitdir = repodir / "manifests.git"
+    gitdir.mkdir(exist_ok=True)
+    (gitdir / "config").write_text(
+        """[remote "origin"]
+            url = https://localhost:0/manifest
+        """,
+        encoding="utf-8",
+    )
+
+    manifest_file.write_text(
+        """
+            <manifest>
+                <remote name="origin" fetch="http://localhost" />
+                <default remote="origin" revision="refs/heads/main" />
+                <project name="proj_g1" path="path_g1" groups="group1" />
+                <project name="proj_g2" path="path_g2" groups="group2" />
+                <project name="proj_g1_g2" path="path_g1_g2"
+                         groups="group1,group2" />
+                <project name="proj_default" path="path_default" />
+                <project name="proj_notdefault" path="path_notdefault"
+                         groups="notdefault" />
+            </manifest>
+        """,
+        encoding="utf-8",
+    )
+
+    for p in [
+        "proj_g1",
+        "proj_g2",
+        "proj_g1_g2",
+        "proj_default",
+        "proj_notdefault",
+    ]:
+        (repodir / "projects" / f"{p}.git").mkdir(parents=True, exist_ok=True)
+
+    return manifest_xml.XmlManifest(str(repodir), str(manifest_file))
+
+
+@pytest.mark.parametrize(
+    "cli_args, expected_projects",
+    [
+        (["-g", "group1"], ["proj_g1", "proj_g1_g2"]),
+        (["-g", "group2"], ["proj_g2", "proj_g1_g2"]),
+        (["-g", "group1,group2"], ["proj_g1", "proj_g1_g2", "proj_g2"]),
+        (["-g", "default,-group1"], ["proj_default", "proj_g2"]),
+        ([], ["proj_default", "proj_g1", "proj_g1_g2", "proj_g2"]),
+    ],
+)
+def test_sync_groups_manifest_filtering(
+    tmp_path: Path, cli_args, expected_projects
+):
+    """Test that repo sync -g selects only matching projects."""
+    manifest = _create_manifest_with_groups(tmp_path)
+    cmd = sync.Sync()
+    cmd.manifest = manifest
+
+    opts, args = cmd.OptionParser.parse_args(cli_args)
+    projects = cmd.GetProjects(args, groups=opts.groups, missing_ok=True)
+    project_names = sorted([p.name for p in projects])
+    assert project_names == sorted(expected_projects)
+
+
+def test_sync_update_projects_revision_id_respects_groups(tmp_path: Path):
+    """Test that _UpdateProjectsRevisionId filters projects using opt.groups."""
+    manifest = _create_manifest_with_groups(tmp_path)
+    cmd = sync.Sync()
+    cmd.manifest = manifest
+
+    superproject = mock.MagicMock()
+    superproject.UpdateProjectsRevisionId.return_value = mock.MagicMock(
+        manifest_path=None
+    )
+    manifest._superproject = superproject
+
+    opts, args = cmd.OptionParser.parse_args(["-g", "group1"])
+    opts.verbose = False
+    opts.fetch_submodules = False
+    opts.this_manifest_only = True
+    opts.local_only = False
+
+    with mock.patch.object(
+        cmd, "GetProjects", wraps=cmd.GetProjects
+    ) as spy_get_projects:
+        with mock.patch.object(cmd, "ManifestList", return_value=[manifest]):
+            cmd._UpdateProjectsRevisionId(opts, args, {}, manifest)
+            spy_get_projects.assert_called_once()
+            _, kwargs = spy_get_projects.call_args
+            assert kwargs.get("groups") == "group1"
+
+
 # Used to patch os.cpu_count() for reliable results.
 OS_CPU_COUNT = 24
 
@@ -335,12 +493,26 @@ class LocalSyncState(unittest.TestCase):
 
 
 class FakeProject:
-    def __init__(self, relpath, name=None, objdir=None):
+    def __init__(
+        self,
+        relpath: str,
+        name: Optional[str] = None,
+        objdir: Optional[str] = None,
+        parent: Optional["FakeProject"] = None,
+        is_derived: bool = False,
+        revisionId: Optional[str] = None,
+        gitlink_path: Optional[str] = None,
+        path_prefix: str = "",
+    ) -> None:
         self.relpath = relpath
+        self.path_prefix = path_prefix
         self.name = name or relpath
         self.objdir = objdir or relpath
         self.worktree = relpath
-        self.parent = None
+        self.parent = parent
+        self.is_derived = is_derived
+        self.revisionId = revisionId
+        self.gitlink_path = gitlink_path
 
         self.use_git_worktrees = False
         self.UseAlternates = False
@@ -349,8 +521,20 @@ class FakeProject:
         self.config = mock.MagicMock()
         self.EnableRepositoryExtension = mock.MagicMock()
 
-    def RelPath(self, local=None):
-        return self.relpath
+    @property
+    def Derived(self) -> bool:
+        return self.is_derived
+
+    def SetRevision(
+        self, revisionExpr: str, revisionId: Optional[str] = None
+    ) -> None:
+        self.revisionExpr = revisionExpr
+        self.revisionId = revisionId or revisionExpr
+
+    def RelPath(self, local: bool = True) -> str:
+        if local:
+            return self.relpath
+        return os.path.join(self.path_prefix, self.relpath)
 
     def __str__(self):
         return f"project: {self.relpath}"
@@ -458,6 +642,159 @@ class SafeCheckoutOrder(unittest.TestCase):
         )
 
 
+class ParentFirstBatches(unittest.TestCase):
+    def test_no_submodules(self) -> None:
+        p_a = FakeProject("a")
+        p_a_b = FakeProject("a/b")
+        out = sync._ParentFirstBatches([p_a, p_a_b])
+        self.assertEqual(out, [[p_a, p_a_b]])
+
+    def test_submodules_follow_their_parent(self) -> None:
+        p_a = FakeProject("a")
+        p_a_b = FakeProject("a/b", parent=p_a, is_derived=True)
+        p_a_b_c = FakeProject("a/b/c", parent=p_a_b, is_derived=True)
+        out = sync._ParentFirstBatches([p_a_b_c, p_a, p_a_b])
+        self.assertEqual(out, [[p_a], [p_a_b], [p_a_b_c]])
+
+
+class RefreshDerivedRevisions(unittest.TestCase):
+    def _parent_with_submodules(self, **gitlinks: str) -> FakeProject:
+        p_a = FakeProject("a")
+        p_a.GetSubmoduleRevisions = mock.Mock(return_value=gitlinks)
+        return p_a
+
+    def _submodule(self, parent: FakeProject, path: str) -> FakeProject:
+        return FakeProject(
+            f"a/{path}", parent=parent, is_derived=True, gitlink_path=path
+        )
+
+    def test_reads_each_parent_once(self) -> None:
+        p_a = self._parent_with_submodules(b="beef1234", c="cafe1234")
+        p_a_b = self._submodule(p_a, "b")
+        p_a_c = self._submodule(p_a, "c")
+
+        sync._RefreshDerivedRevisions([p_a, p_a_b, p_a_c])
+
+        p_a.GetSubmoduleRevisions.assert_called_once_with()
+        self.assertEqual(p_a_b.revisionId, "beef1234")
+        self.assertEqual(p_a_c.revisionId, "cafe1234")
+
+    def test_reuses_gitlinks_read_for_an_earlier_level(self) -> None:
+        p_a = self._parent_with_submodules(b="beef1234", c="cafe1234")
+        p_a_b = self._submodule(p_a, "b")
+        p_a_c = self._submodule(p_a, "c")
+        submodule_revisions = {}
+
+        sync._RefreshDerivedRevisions([p_a_b], submodule_revisions)
+        sync._RefreshDerivedRevisions([p_a_c], submodule_revisions)
+
+        p_a.GetSubmoduleRevisions.assert_called_once_with()
+        self.assertEqual(p_a_c.revisionId, "cafe1234")
+
+    def test_tells_apart_projects_with_the_same_path(self) -> None:
+        # Paths are relative to their own (sub)manifest, so two projects can
+        # share one.
+        first = self._parent_with_submodules(b="beef1234")
+        second = self._parent_with_submodules(b="cafe1234")
+        first_sub = self._submodule(first, "b")
+        second_sub = self._submodule(second, "b")
+        submodule_revisions = {}
+
+        sync._RefreshDerivedRevisions([first_sub], submodule_revisions)
+        sync._RefreshDerivedRevisions([second_sub], submodule_revisions)
+
+        self.assertEqual(first_sub.revisionId, "beef1234")
+        self.assertEqual(second_sub.revisionId, "cafe1234")
+
+    def test_ignores_projects_from_the_manifest(self) -> None:
+        p_a = self._parent_with_submodules()
+
+        sync._RefreshDerivedRevisions([p_a])
+
+        p_a.GetSubmoduleRevisions.assert_not_called()
+
+    def test_reports_submodules_removed_from_their_parent(self) -> None:
+        p_a = self._parent_with_submodules(b="beef1234")
+        p_a_c = self._submodule(p_a, "c")
+
+        removed = sync._RefreshDerivedRevisions([p_a, p_a_c])
+
+        self.assertEqual(removed, [p_a_c])
+
+    def test_keeps_submodules_of_an_unreadable_parent(self) -> None:
+        p_a = FakeProject("a")
+        p_a.GetSubmoduleRevisions = mock.Mock(return_value=None)
+        p_a_b = FakeProject(
+            "a/b",
+            parent=p_a,
+            is_derived=True,
+            revisionId="stale",
+            gitlink_path="b",
+        )
+
+        removed = sync._RefreshDerivedRevisions([p_a, p_a_b])
+
+        self.assertEqual(removed, [])
+        self.assertEqual(p_a_b.revisionId, "stale")
+
+
+class FetchParentFirst(unittest.TestCase):
+    def test_submodules_are_fetched_after_their_parent(self) -> None:
+        cmd = sync.Sync()
+        cmd._fetch_times = mock.Mock()
+        cmd._fetch_times.Get = mock.Mock(return_value=0)
+
+        calls = []
+        p_a = FakeProject("a")
+
+        def fake_read() -> Dict[str, str]:
+            calls.append(("read gitlinks of", p_a.relpath))
+            return {"b": "beef1234"}
+
+        p_a.GetSubmoduleRevisions = mock.Mock(side_effect=fake_read)
+        p_a_b = FakeProject(
+            "a/b", parent=p_a, is_derived=True, gitlink_path="b"
+        )
+
+        def fake_fetch(
+            projects: List[FakeProject], *_args: object
+        ) -> sync._FetchResult:
+            calls.append(("fetch", [p.relpath for p in projects]))
+            return sync._FetchResult(True, {p.objdir for p in projects})
+
+        opt = mock.Mock(fail_fast=False)
+        with mock.patch.object(cmd, "_Fetch", side_effect=fake_fetch):
+            result = cmd._FetchParentFirst([p_a_b, p_a], opt, None, None, [])
+
+        self.assertTrue(result.success)
+        self.assertEqual(result.projects, {"a", "a/b"})
+        self.assertEqual(
+            calls,
+            [
+                ("fetch", ["a"]),
+                ("read gitlinks of", "a"),
+                ("fetch", ["a/b"]),
+            ],
+        )
+
+
+class WithoutProjects(unittest.TestCase):
+    def test_drops_the_unwanted_projects(self) -> None:
+        p_a = FakeProject("a")
+        p_a_b = FakeProject("a/b")
+        self.assertEqual(sync._WithoutProjects([p_a, p_a_b], [p_a_b]), [p_a])
+        self.assertEqual(sync._WithoutProjects([p_a, p_a_b], []), [p_a, p_a_b])
+
+    def test_keeps_projects_with_the_same_path(self) -> None:
+        # Paths are relative to their own (sub)manifest, so two projects can
+        # share one.
+        first = FakeProject("a/b")
+        second = FakeProject("a/b")
+        self.assertEqual(
+            sync._WithoutProjects([first, second], [second]), [first]
+        )
+
+
 class Chunksize(unittest.TestCase):
     """Tests for _chunksize."""
 
@@ -792,6 +1129,19 @@ class SyncCommand(unittest.TestCase):
             self.assertIn(self.sync_local_half_error, e.aggregate_errors)
             self.assertIn(self.sync_network_half_error, e.aggregate_errors)
 
+    def test_groups_passed_to_get_projects(self):
+        """Ensure Execute passes opt.groups to GetProjects."""
+        self.opt.groups = "my_group"
+        self.opt.mp_update = False
+        with mock.patch.object(self.cmd, "_UpdateRepoProject"):
+            with mock.patch.object(self.cmd, "_ValidateOptionsWithManifest"):
+                with mock.patch.object(self.cmd, "_SyncInterleaved"):
+                    with mock.patch.object(self.cmd, "_RunPostSyncHook"):
+                        self.cmd.Execute(self.opt, [])
+        self.cmd.GetProjects.assert_called()
+        _, kwargs = self.cmd.GetProjects.call_args
+        self.assertEqual(kwargs.get("groups"), "my_group")
+
 
 class SyncUpdateRepoProject(unittest.TestCase):
     """Tests for Sync._UpdateRepoProject."""
@@ -989,6 +1339,203 @@ class InterleavedSyncTest(unittest.TestCase):
 
         execute_mock.assert_called_once()
 
+    def test_interleaved_refreshes_submodule_revision(self) -> None:
+        """Test submodules are synced at the revision of the fetched parent."""
+        opt, args = self.cmd.OptionParser.parse_args(["--interleaved", "-j4"])
+        opt.quiet = True
+
+        submodule = FakeProject(
+            "projA/sub",
+            name="projA_sub",
+            objdir="objA_sub",
+            parent=self.projA,
+            is_derived=True,
+            revisionId="stale",
+            gitlink_path="sub",
+        )
+        all_projects = [self.projA, submodule]
+        mock.patch.object(
+            self.cmd, "GetProjects", return_value=all_projects
+        ).start()
+
+        self.projA.GetSubmoduleRevisions = mock.Mock(
+            return_value={"sub": "fetched"}
+        )
+
+        synced = []
+
+        def execute_side_effect(
+            jobs: int,
+            target: object,
+            work_items: List[List[int]],
+            **kwargs: object,
+        ) -> bool:
+            synced_relpaths_set = kwargs["callback"].args[0]
+            projects_in_pass = self.cmd.get_parallel_context()["projects"]
+            for item in work_items:
+                for project_idx in item:
+                    project = projects_in_pass[project_idx]
+                    synced.append((project.relpath, project.revisionId))
+                    synced_relpaths_set.add(project.relpath)
+            return True
+
+        mock.patch.object(
+            self.cmd, "ExecuteInParallel", side_effect=execute_side_effect
+        ).start()
+
+        self.cmd._SyncInterleaved(
+            opt,
+            args,
+            [],
+            self.manifest,
+            self.manifest.manifestProject,
+            all_projects,
+            {},
+        )
+
+        self.assertIn(("projA/sub", "fetched"), synced)
+
+    def test_interleaved_skips_removed_submodule(self) -> None:
+        """Test submodules dropped by their parent are not checked out."""
+        opt, args = self.cmd.OptionParser.parse_args(["--interleaved", "-j4"])
+        opt.quiet = True
+
+        submodule = FakeProject(
+            "projA/sub",
+            name="projA_sub",
+            objdir="objA_sub",
+            parent=self.projA,
+            is_derived=True,
+            revisionId="stale",
+            gitlink_path="sub",
+        )
+        # The parent no longer holds a gitlink for the submodule.
+        self.projA.GetSubmoduleRevisions = mock.Mock(return_value={})
+        # The reloaded manifest no longer derives the removed submodule.
+        mock.patch.object(
+            self.cmd, "GetProjects", return_value=[self.projA]
+        ).start()
+
+        synced = []
+
+        def execute_side_effect(
+            jobs: int,
+            target: object,
+            work_items: List[List[int]],
+            **kwargs: object,
+        ) -> bool:
+            synced_relpaths_set = kwargs["callback"].args[0]
+            projects_in_pass = self.cmd.get_parallel_context()["projects"]
+            for item in work_items:
+                for project_idx in item:
+                    project = projects_in_pass[project_idx]
+                    synced.append(project.relpath)
+                    synced_relpaths_set.add(project.relpath)
+            return True
+
+        mock.patch.object(
+            self.cmd, "ExecuteInParallel", side_effect=execute_side_effect
+        ).start()
+
+        self.cmd._SyncInterleaved(
+            opt,
+            args,
+            [],
+            self.manifest,
+            self.manifest.manifestProject,
+            [self.projA, submodule],
+            {},
+        )
+
+        self.assertEqual(synced, ["projA"])
+
+    def _make_syncable(self, project: FakeProject) -> FakeProject:
+        project.Sync_NetworkHalf = mock.Mock(
+            return_value=SyncNetworkHalfResult(error=None, remote_fetched=True)
+        )
+        project.Sync_LocalHalf = mock.Mock()
+        return project
+
+    def _run_interleaved(
+        self,
+        opt: optparse.Values,
+        initial_projects: List[FakeProject],
+        reloaded_projects: List[FakeProject],
+    ) -> None:
+        """Run _SyncInterleaved with the real workers and callback.
+
+        |initial_projects| make up the first pass, |reloaded_projects| every
+        later one, the way reloading the manifest between passes does.
+        """
+        mock.patch.object(
+            self.cmd, "GetProjects", return_value=reloaded_projects
+        ).start()
+        mock.patch.object(self.cmd, "event_log").start()
+
+        def execute_side_effect(
+            jobs: int,
+            target: object,
+            work_items: List[List[int]],
+            **kwargs: object,
+        ) -> bool:
+            results = [target(item) for item in work_items]
+            return kwargs["callback"](None, kwargs["output"], results)
+
+        mock.patch.object(
+            self.cmd, "ExecuteInParallel", side_effect=execute_side_effect
+        ).start()
+
+        with mock.patch("subcmds.sync.SyncBuffer") as mock_sync_buffer:
+            mock_sync_buffer.return_value.Finish.return_value = True
+            mock_sync_buffer.return_value.errors = []
+            self.cmd._SyncInterleaved(
+                opt,
+                [],
+                [],
+                self.manifest,
+                self.manifest.manifestProject,
+                initial_projects,
+                {},
+            )
+
+    def test_interleaved_syncs_same_path_projects_of_every_manifest(
+        self,
+    ) -> None:
+        """Test a project is not skipped because another shares its path."""
+        opt = self._get_opts(["--interleaved", "-j4"])
+        outer = self._make_syncable(
+            FakeProject("foo", name="outer", objdir="a")
+        )
+        sub = self._make_syncable(
+            FakeProject("foo", name="sub", objdir="b", path_prefix="sub")
+        )
+
+        # |sub| is only discovered once the manifest is reloaded after the
+        # first pass has synced |outer|.
+        self._run_interleaved(opt, [outer], [outer, sub])
+
+        outer.Sync_LocalHalf.assert_called_once()
+        sub.Sync_LocalHalf.assert_called_once()
+
+    def test_interleaved_reports_failures_by_a_unique_path(self) -> None:
+        """Test failing projects are listed by a path that is theirs alone."""
+        opt = self._get_opts(["--interleaved", "-j4"])
+        outer = self._make_syncable(
+            FakeProject("foo", name="outer", objdir="a")
+        )
+        sub = self._make_syncable(
+            FakeProject("foo", name="sub", objdir="b", path_prefix="sub")
+        )
+        sub.Sync_LocalHalf.side_effect = GitError("checkout failed")
+        self.cmd.git_event_log = mock.MagicMock()
+
+        with self.assertRaises(sync.SyncError):
+            self._run_interleaved(opt, [outer, sub], [outer, sub])
+
+        self.assertEqual(
+            self.cmd._interleaved_err_checkout_results, ["sub/foo"]
+        )
+
     def test_interleaved_shared_objdir_serial(self):
         """Test that projects with shared objdir are processed serially."""
         opt, args = self.cmd.OptionParser.parse_args(["--interleaved", "-j4"])
@@ -1083,6 +1630,23 @@ class InterleavedSyncTest(unittest.TestCase):
             project.Sync_NetworkHalf.assert_called_once()
             project.Sync_LocalHalf.assert_called_once()
 
+    def test_worker_reports_a_path_unique_across_manifests(self) -> None:
+        """Test _SyncResult.relpath tells apart same-path projects."""
+        project = FakeProject("foo", objdir="objA", path_prefix="sub")
+        self._make_syncable(project)
+        self.mock_context["projects"] = [project]
+
+        for this_manifest_only, expected in ((False, "sub/foo"), (True, "foo")):
+            with self.subTest(this_manifest_only=this_manifest_only):
+                opt = self._get_opts()
+                opt.this_manifest_only = this_manifest_only
+                with mock.patch("subcmds.sync.SyncBuffer") as mock_sync_buffer:
+                    mock_sync_buffer.return_value.Finish.return_value = True
+                    mock_sync_buffer.return_value.errors = []
+                    result_obj = self.cmd._SyncProjectList(opt, [0])
+
+                self.assertEqual(result_obj.results[0].relpath, expected)
+
     def test_worker_fetch_fails(self):
         """Test _SyncProjectList with a failed fetch."""
         opt = self._get_opts()

tests/test_subcmds_upload.py

@@ -63,3 +63,57 @@ def test_UploadAndReport_UnhandledError(cmd: upload.Upload) -> None:
     with mock.patch.object(cmd, "_UploadBranch", side_effect=UnexpectedError):
         with pytest.raises(UnexpectedError):
             cmd._UploadAndReport(opt, [mock.MagicMock()], _STUB_PEOPLE)
+
+
+def test_GetMergeBranch_explicit_branch(cmd: upload.Upload) -> None:
+    """Verify _GetMergeBranch reads branch.merge for explicit local_branch."""
+    mock_project = mock.MagicMock()
+    mock_branch = mock.MagicMock()
+    mock_branch.merge = "refs/heads/main"
+    mock_project.GetBranch.return_value = mock_branch
+
+    res = cmd._GetMergeBranch(mock_project, local_branch="feature")
+    assert res == "refs/heads/main"
+    mock_project.GetBranch.assert_called_once_with("feature")
+
+
+def test_GetMergeBranch_current_branch(cmd: upload.Upload) -> None:
+    """Verify _GetMergeBranch falls back to project.CurrentBranch."""
+    mock_project = mock.MagicMock()
+    mock_project.CurrentBranch = "auto-cbr"
+    mock_branch = mock.MagicMock()
+    mock_branch.merge = "refs/heads/upstream-main"
+    mock_project.GetBranch.return_value = mock_branch
+
+    res = cmd._GetMergeBranch(mock_project, local_branch=None)
+    assert res == "refs/heads/upstream-main"
+    mock_project.GetBranch.assert_called_once_with("auto-cbr")
+
+
+def test_GetMergeBranch_none_when_no_branch(cmd: upload.Upload) -> None:
+    """Verify _GetMergeBranch returns empty string when detached HEAD."""
+    mock_project = mock.MagicMock()
+    mock_project.CurrentBranch = None
+
+    res = cmd._GetMergeBranch(mock_project, local_branch=None)
+    assert res == ""
+
+
+def test_GatherOne_returns_resolved_current_branch(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Upload error reporting reuses the branch gathered by the worker."""
+    project = mock.MagicMock()
+    project.CurrentBranch = "topic"
+    branch = mock.sentinel.branch
+    project.GetUploadableBranch.return_value = branch
+    monkeypatch.setattr(
+        upload.Upload,
+        "get_parallel_context",
+        lambda: {"projects": [project]},
+    )
+    opt = mock.MagicMock(current_branch=True)
+
+    assert upload.Upload._GatherOne(opt, 0) == (0, [branch], "topic")
+
+    project.GetUploadableBranch.assert_called_once_with("topic")

tests/test_subcmds_version.py

@@ -0,0 +1,52 @@
+# Copyright (C) 2026 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Unittests for subcmds/version.py."""
+
+from unittest import mock
+
+import pytest
+
+from subcmds import version
+
+
+def test_repo_version_uses_one_pretty_format_call(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    project = mock.MagicMock()
+    project.bare_git.log.return_value = "v2.0-1-g12345678\nTue, 25 Aug\n"
+    monkeypatch.setattr(version, "git_require", lambda _version: True)
+
+    result = version.Version._RepoVersion(project)
+
+    assert result == ("v2.0-1-g12345678", "Tue, 25 Aug")
+    project.bare_git.log.assert_called_once_with(
+        "-1", "--format=%(describe)%n%cD", "HEAD"
+    )
+    project.bare_git.describe.assert_not_called()
+
+
+def test_repo_version_keeps_old_git_fallback(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    project = mock.MagicMock()
+    project.bare_git.describe.return_value = "v2.0"
+    project.bare_git.log.return_value = "Tue, 25 Aug"
+    monkeypatch.setattr(version, "git_require", lambda _version: False)
+
+    result = version.Version._RepoVersion(project)
+
+    assert result == ("v2.0", "Tue, 25 Aug")
+    project.bare_git.describe.assert_called_once_with("HEAD")
+    project.bare_git.log.assert_called_once_with("-1", "--format=%cD", "HEAD")