sync: fix connection error on macOS

With a large number of sync workers, the sync process may fail on macOS due to connection errors. The root cause is that multiple workers may attempt to connect to the multiprocessing manager server at the same time when handling the first job. This can lead to connection failures if there are too many pending connections, exceeding the socket listening backlog. Bug: 377538810 Change-Id: I1924d318d076ca3be61d75daa37bfa8d7dc23ed7 Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/441541 Tested-by: Josip Sokcevic <sokcevic@google.com> Commit-Queue: Josip Sokcevic <sokcevic@google.com> Reviewed-by: Josip Sokcevic <sokcevic@google.com>
upload: Return correct tuple values in _ProcessResults
2025-06-26 20:17:52 +00:00 · 2024-11-06 16:33:17 +00:00 · 2024-10-31 21:18:53 +00:00 · 2024-10-30 17:03:57 +00:00 · 2024-10-30 16:11:04 +00:00 · 2024-10-28 23:47:08 +00:00
48 changed files with 1229 additions and 747 deletions
--- a/color.py
+++ b/color.py
@ -210,6 +210,7 @@ class Coloring:
                if have_fg:
                    bg = a
                else:
+                    have_fg = True
                    fg = a
            elif is_attr(a):
                attr = a
--- a/command.py
+++ b/command.py
@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.

+import contextlib
 import multiprocessing
 import optparse
 import os
@ -70,6 +71,14 @@ class Command:
    # migrated subcommands can set it to False.
    MULTI_MANIFEST_SUPPORT = True

+    # Shared data across parallel execution workers.
+    _parallel_context = None
+
+    @classmethod
+    def get_parallel_context(cls):
+        assert cls._parallel_context is not None
+        return cls._parallel_context
+
    def __init__(
        self,
        repodir=None,
@ -242,9 +251,39 @@ class Command:
        """Perform the action, after option parsing is complete."""
        raise NotImplementedError

-    @staticmethod
+    @classmethod
+    @contextlib.contextmanager
+    def ParallelContext(cls):
+        """Obtains the context, which is shared to ExecuteInParallel workers.
+
+        Callers can store data in the context dict before invocation of
+        ExecuteInParallel. The dict will then be shared to child workers of
+        ExecuteInParallel.
+        """
+        assert cls._parallel_context is None
+        cls._parallel_context = {}
+        try:
+            yield
+        finally:
+            cls._parallel_context = None
+
+    @classmethod
+    def _InitParallelWorker(cls, context, initializer):
+        cls._parallel_context = context
+        if initializer:
+            initializer()
+
+    @classmethod
    def ExecuteInParallel(
-        jobs, func, inputs, callback, output=None, ordered=False
+        cls,
+        jobs,
+        func,
+        inputs,
+        callback,
+        output=None,
+        ordered=False,
+        chunksize=WORKER_BATCH_SIZE,
+        initializer=None,
    ):
        """Helper for managing parallel execution boiler plate.

@ -269,6 +308,9 @@ class Command:
            output: An output manager. May be progress.Progess or
                color.Coloring.
            ordered: Whether the jobs should be processed in order.
+            chunksize: The number of jobs processed in batch by parallel
+                workers.
+            initializer: Worker initializer.

        Returns:
            The |callback| function's results are returned.
@ -278,12 +320,16 @@ class Command:
            if len(inputs) == 1 or jobs == 1:
                return callback(None, output, (func(x) for x in inputs))
            else:
-                with multiprocessing.Pool(jobs) as pool:
+                with multiprocessing.Pool(
+                    jobs,
+                    initializer=cls._InitParallelWorker,
+                    initargs=(cls._parallel_context, initializer),
+                ) as pool:
                    submit = pool.imap if ordered else pool.imap_unordered
                    return callback(
                        pool,
                        output,
-                        submit(func, inputs, chunksize=WORKER_BATCH_SIZE),
+                        submit(func, inputs, chunksize=chunksize),
                    )
        finally:
            if isinstance(output, progress.Progress):
--- a/constraints.txt
+++ b/constraints.txt
@ -0,0 +1 @@
+black<24
--- a/docs/manifest-format.md
+++ b/docs/manifest-format.md
@ -107,11 +107,13 @@ following DTD:
  <!ATTLIST extend-project remote CDATA #IMPLIED>
  <!ATTLIST extend-project dest-branch CDATA #IMPLIED>
  <!ATTLIST extend-project upstream CDATA #IMPLIED>
+  <!ATTLIST extend-project base-rev CDATA #IMPLIED>

  <!ELEMENT remove-project EMPTY>
  <!ATTLIST remove-project name     CDATA #IMPLIED>
  <!ATTLIST remove-project path     CDATA #IMPLIED>
  <!ATTLIST remove-project optional CDATA #IMPLIED>
+  <!ATTLIST remove-project base-rev CDATA #IMPLIED>

  <!ELEMENT repo-hooks EMPTY>
  <!ATTLIST repo-hooks in-project CDATA #REQUIRED>
@ -433,6 +435,14 @@ project.  Same syntax as the corresponding element of `project`.
 Attribute `upstream`: If specified, overrides the upstream of the original
 project.  Same syntax as the corresponding element of `project`.

+Attribute `base-rev`: If specified, adds a check against the revision
+to be extended. Manifest parse will fail and give a list of mismatch extends
+if the revisions being extended have changed since base-rev was set.
+Intended for use with layered manifests using hash revisions to prevent
+patch branches hiding newer upstream revisions. Also compares named refs
+like branches or tags but is misleading if branches are used as base-rev.
+Same syntax as the corresponding element of `project`.
+
 ### Element annotation

 Zero or more annotation elements may be specified as children of a
@ -496,6 +506,14 @@ name. Logic otherwise behaves like both are specified.
 Attribute `optional`: Set to true to ignore remove-project elements with no
 matching `project` element.

+Attribute `base-rev`: If specified, adds a check against the revision
+to be removed. Manifest parse will fail and give a list of mismatch removes
+if the revisions being removed have changed since base-rev was set.
+Intended for use with layered manifests using hash revisions to prevent
+patch branches hiding newer upstream revisions. Also compares named refs
+like branches or tags but is misleading if branches are used as base-rev.
+Same syntax as the corresponding element of `project`.
+
 ### Element repo-hooks

 NB: See the [practical documentation](./repo-hooks.md) for using repo hooks.
--- a/docs/release-process.md
+++ b/docs/release-process.md
@ -96,6 +96,9 @@ If that tag is valid, then repo will warn and use that commit instead.

 If that tag cannot be verified, it gives up and forces the user to resolve.

+If env variable `REPO_SKIP_SELF_UPDATE` is defined, this will
+bypass the self update algorithm.
+
 ### Force an update

 The `repo selfupdate` command can be used to force an immediate update.
--- a/error.py
+++ b/error.py
@ -107,6 +107,10 @@ class GitError(RepoError):
        return self.message


+class GitAuthError(RepoExitError):
+    """Cannot talk to remote due to auth issue."""
+
+
 class GitcUnsupportedError(RepoExitError):
    """Gitc no longer supported."""

--- a/event_log.py
+++ b/event_log.py
@ -168,8 +168,10 @@ class EventLog:
                f.write("\n")


-# An integer id that is unique across this invocation of the program.
-_EVENT_ID = multiprocessing.Value("i", 1)
+# An integer id that is unique across this invocation of the program, to be set
+# by the first Add event. We can't set it here since it results in leaked
+# resources (see: https://issues.gerritcodereview.com/353656374).
+_EVENT_ID = None


 def _NextEventId():
@ -178,6 +180,12 @@ def _NextEventId():
    Returns:
        A unique, to this invocation of the program, integer id.
    """
+    global _EVENT_ID
+    if _EVENT_ID is None:
+        # There is a small chance of race condition - two parallel processes
+        # setting up _EVENT_ID. However, we expect TASK_COMMAND to happen before
+        # mp kicks in.
+        _EVENT_ID = multiprocessing.Value("i", 1)
    with _EVENT_ID.get_lock():
        val = _EVENT_ID.value
        _EVENT_ID.value += 1
--- a/git_command.py
+++ b/git_command.py
@ -33,17 +33,6 @@ from wrapper import Wrapper


 GIT = "git"
-# NB: These do not need to be kept in sync with the repo launcher script.
-# These may be much newer as it allows the repo launcher to roll between
-# different repo releases while source versions might require a newer git.
-#
-# The soft version is when we start warning users that the version is old and
-# we'll be dropping support for it.  We'll refuse to work with versions older
-# than the hard version.
-#
-# git-1.7 is in (EOL) Ubuntu Precise.  git-1.9 is in Ubuntu Trusty.
-MIN_GIT_VERSION_SOFT = (1, 9, 1)
-MIN_GIT_VERSION_HARD = (1, 7, 2)
 GIT_DIR = "GIT_DIR"

 LAST_GITDIR = None
@ -324,12 +313,15 @@ class GitCommand:
            cwd = None
        command_name = cmdv[0]
        command.append(command_name)
-        # Need to use the --progress flag for fetch/clone so output will be
-        # displayed as by default git only does progress output if stderr is a
-        # TTY.
-        if sys.stderr.isatty() and command_name in ("fetch", "clone"):
-            if "--progress" not in cmdv and "--quiet" not in cmdv:
-                command.append("--progress")
+
+        if command_name in ("fetch", "clone"):
+            env["GIT_TERMINAL_PROMPT"] = "0"
+            # Need to use the --progress flag for fetch/clone so output will be
+            # displayed as by default git only does progress output if stderr is
+            # a TTY.
+            if sys.stderr.isatty():
+                if "--progress" not in cmdv and "--quiet" not in cmdv:
+                    command.append("--progress")
        command.extend(cmdv[1:])

        event_log = (
--- a/git_superproject.py
+++ b/git_superproject.py
@ -307,8 +307,6 @@ class Superproject:
            )
            return SyncResult(False, False)

-        _PrintBetaNotice()
-
        should_exit = True
        if not self._remote_url:
            self._LogWarning(
@ -452,16 +450,6 @@ class Superproject:
        return UpdateProjectsResult(manifest_path, False)


-@functools.lru_cache(maxsize=10)
-def _PrintBetaNotice():
-    """Print the notice of beta status."""
-    print(
-        "NOTICE: --use-superproject is in beta; report any issues to the "
-        "address described in `repo version`",
-        file=sys.stderr,
-    )
-
-
@functools.lru_cache(maxsize=None)
 def _UseSuperprojectFromConfiguration():
    """Returns the user choice of whether to use superproject."""
--- a/hooks/commit-msg
+++ b/hooks/commit-msg
@ -1,5 +1,8 @@
 #!/bin/sh
-# From Gerrit Code Review 3.10.0 d5403dbf335ba7d48977fc95170c3f7027c34659
+# DO NOT EDIT THIS FILE
+# All updates should be sent upstream: https://gerrit.googlesource.com/gerrit/
+# This is synced from commit: 62f5bbea67f6dafa6e22a601a0c298214c510caf
+# DO NOT EDIT THIS FILE
 #
 # Part of Gerrit Code Review (https://www.gerritcodereview.com/)
 #
@ -31,8 +34,7 @@ if test ! -f "$1" ; then
 fi

 # Do not create a change id if requested
-create_setting=$(git config --get gerrit.createChangeId)
-case "$create_setting" in
+case "$(git config --get gerrit.createChangeId)" in
  false)
    exit 0
    ;;
--- a/hooks/pre-auto-gc
+++ b/hooks/pre-auto-gc
@ -1,33 +1,25 @@
 #!/bin/sh
+# DO NOT EDIT THIS FILE
+# All updates should be sent upstream: https://github.com/git/git
+# This is synced from commit: 00e10ef10e161a913893b8cb33aa080d4ca5baa6
+# DO NOT EDIT THIS FILE
 #
 # An example hook script to verify if you are on battery, in case you
-# are running Windows, Linux or OS X. Called by git-gc --auto with no
-# arguments. The hook should exit with non-zero status after issuing an
-# appropriate message if it wants to stop the auto repacking.
-
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
+# are running Linux or OS X. Called by git-gc --auto with no arguments.
+# The hook should exit with non-zero status after issuing an appropriate
+# message if it wants to stop the auto repacking.
 #
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
+# This hook is stored in the contrib/hooks directory. Your distribution
+# may have put this somewhere else. If you want to use this hook, you
+# should make this script executable then link to it in the repository
+# you would like to use it in.
 #
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-if uname -s | grep -q "_NT-"
-then
-	if test -x $SYSTEMROOT/System32/Wbem/wmic
-	then
-		STATUS=$(wmic path win32_battery get batterystatus /format:list | tr -d '\r\n')
-		[ "$STATUS" = "BatteryStatus=2" ] && exit 0 || exit 1
-	fi
-	exit 0
-fi
+# For example, if the hook is stored in
+# /usr/share/git-core/contrib/hooks/pre-auto-gc-battery:
+#
+# cd /path/to/your/repository.git
+# ln -sf /usr/share/git-core/contrib/hooks/pre-auto-gc-battery \
+#	hooks/pre-auto-gc

 if test -x /sbin/on_ac_power && (/sbin/on_ac_power;test $? -ne 1)
 then
@ -48,11 +40,6 @@ elif test -x /usr/bin/pmset && /usr/bin/pmset -g batt |
 	grep -q "drawing from 'AC Power'"
 then
 	exit 0
-elif test -d /sys/bus/acpi/drivers/battery && test 0 = \
-  "$(find /sys/bus/acpi/drivers/battery/ -type l | wc -l)";
-then
-	# No battery exists.
-	exit 0
 fi

 echo "Auto packing deferred; not on AC"
--- a/man/repo-gitc-delete.1
+++ b/man/repo-gitc-delete.1
@ -1,44 +0,0 @@
-.\" DO NOT MODIFY THIS FILE!  It was generated by help2man.
-.TH REPO "1" "July 2022" "repo gitc-delete" "Repo Manual"
-.SH NAME
-repo \- repo gitc-delete - manual page for repo gitc-delete
-.SH SYNOPSIS
-.B repo
-\fI\,gitc-delete\/\fR
-.SH DESCRIPTION
-Summary
-.PP
-Delete a GITC Client.
-.SH OPTIONS
-.TP
-\fB\-h\fR, \fB\-\-help\fR
-show this help message and exit
-.TP
-\fB\-f\fR, \fB\-\-force\fR
-force the deletion (no prompt)
-.SS Logging options:
-.TP
-\fB\-v\fR, \fB\-\-verbose\fR
-show all output
-.TP
-\fB\-q\fR, \fB\-\-quiet\fR
-only show errors
-.SS Multi\-manifest options:
-.TP
-\fB\-\-outer\-manifest\fR
-operate starting at the outermost manifest
-.TP
-\fB\-\-no\-outer\-manifest\fR
-do not operate on outer manifests
-.TP
-\fB\-\-this\-manifest\-only\fR
-only operate on this (sub)manifest
-.TP
-\fB\-\-no\-this\-manifest\-only\fR, \fB\-\-all\-manifests\fR
-operate on this manifest and its submanifests
-.PP
-Run `repo help gitc\-delete` to view the detailed manual.
-.SH DETAILS
-.PP
-This subcommand deletes the current GITC client, deleting the GITC manifest and
-all locally downloaded sources.
--- a/man/repo-gitc-init.1
+++ b/man/repo-gitc-init.1
@ -1,175 +0,0 @@
-.\" DO NOT MODIFY THIS FILE!  It was generated by help2man.
-.TH REPO "1" "October 2022" "repo gitc-init" "Repo Manual"
-.SH NAME
-repo \- repo gitc-init - manual page for repo gitc-init
-.SH SYNOPSIS
-.B repo
-\fI\,gitc-init \/\fR[\fI\,options\/\fR] [\fI\,client name\/\fR]
-.SH DESCRIPTION
-Summary
-.PP
-Initialize a GITC Client.
-.SH OPTIONS
-.TP
-\fB\-h\fR, \fB\-\-help\fR
-show this help message and exit
-.SS Logging options:
-.TP
-\fB\-v\fR, \fB\-\-verbose\fR
-show all output
-.TP
-\fB\-q\fR, \fB\-\-quiet\fR
-only show errors
-.SS Manifest options:
-.TP
-\fB\-u\fR URL, \fB\-\-manifest\-url\fR=\fI\,URL\/\fR
-manifest repository location
-.TP
-\fB\-b\fR REVISION, \fB\-\-manifest\-branch\fR=\fI\,REVISION\/\fR
-manifest branch or revision (use HEAD for default)
-.TP
-\fB\-m\fR NAME.xml, \fB\-\-manifest\-name\fR=\fI\,NAME\/\fR.xml
-initial manifest file
-.TP
-\fB\-g\fR GROUP, \fB\-\-groups\fR=\fI\,GROUP\/\fR
-restrict manifest projects to ones with specified
-group(s) [default|all|G1,G2,G3|G4,\-G5,\-G6]
-.TP
-\fB\-p\fR PLATFORM, \fB\-\-platform\fR=\fI\,PLATFORM\/\fR
-restrict manifest projects to ones with a specified
-platform group [auto|all|none|linux|darwin|...]
-.TP
-\fB\-\-submodules\fR
-sync any submodules associated with the manifest repo
-.TP
-\fB\-\-standalone\-manifest\fR
-download the manifest as a static file rather then
-create a git checkout of the manifest repo
-.TP
-\fB\-\-manifest\-depth\fR=\fI\,DEPTH\/\fR
-create a shallow clone of the manifest repo with given
-depth (0 for full clone); see git clone (default: 0)
-.SS Manifest (only) checkout options:
-.TP
-\fB\-\-current\-branch\fR
-fetch only current manifest branch from server
-(default)
-.TP
-\fB\-\-no\-current\-branch\fR
-fetch all manifest branches from server
-.TP
-\fB\-\-tags\fR
-fetch tags in the manifest
-.TP
-\fB\-\-no\-tags\fR
-don't fetch tags in the manifest
-.SS Checkout modes:
-.TP
-\fB\-\-mirror\fR
-create a replica of the remote repositories rather
-than a client working directory
-.TP
-\fB\-\-archive\fR
-checkout an archive instead of a git repository for
-each project. See git archive.
-.TP
-\fB\-\-worktree\fR
-use git\-worktree to manage projects
-.SS Project checkout optimizations:
-.TP
-\fB\-\-reference\fR=\fI\,DIR\/\fR
-location of mirror directory
-.TP
-\fB\-\-dissociate\fR
-dissociate from reference mirrors after clone
-.TP
-\fB\-\-depth\fR=\fI\,DEPTH\/\fR
-create a shallow clone with given depth; see git clone
-.TP
-\fB\-\-partial\-clone\fR
-perform partial clone (https://gitscm.com/docs/gitrepositorylayout#_code_partialclone_code)
-.TP
-\fB\-\-no\-partial\-clone\fR
-disable use of partial clone (https://gitscm.com/docs/gitrepositorylayout#_code_partialclone_code)
-.TP
-\fB\-\-partial\-clone\-exclude\fR=\fI\,PARTIAL_CLONE_EXCLUDE\/\fR
-exclude the specified projects (a comma\-delimited
-project names) from partial clone (https://gitscm.com/docs/gitrepositorylayout#_code_partialclone_code)
-.TP
-\fB\-\-clone\-filter\fR=\fI\,CLONE_FILTER\/\fR
-filter for use with \fB\-\-partial\-clone\fR [default:
-blob:none]
-.TP
-\fB\-\-use\-superproject\fR
-use the manifest superproject to sync projects;
-implies \fB\-c\fR
-.TP
-\fB\-\-no\-use\-superproject\fR
-disable use of manifest superprojects
-.TP
-\fB\-\-clone\-bundle\fR
-enable use of \fI\,/clone.bundle\/\fP on HTTP/HTTPS (default if
-not \fB\-\-partial\-clone\fR)
-.TP
-\fB\-\-no\-clone\-bundle\fR
-disable use of \fI\,/clone.bundle\/\fP on HTTP/HTTPS (default if
-\fB\-\-partial\-clone\fR)
-.TP
-\fB\-\-git\-lfs\fR
-enable Git LFS support
-.TP
-\fB\-\-no\-git\-lfs\fR
-disable Git LFS support
-.SS repo Version options:
-.TP
-\fB\-\-repo\-url\fR=\fI\,URL\/\fR
-repo repository location ($REPO_URL)
-.TP
-\fB\-\-repo\-rev\fR=\fI\,REV\/\fR
-repo branch or revision ($REPO_REV)
-.TP
-\fB\-\-no\-repo\-verify\fR
-do not verify repo source code
-.SS Other options:
-.TP
-\fB\-\-config\-name\fR
-Always prompt for name/e\-mail
-.SS GITC options:
-.TP
-\fB\-f\fR MANIFEST_FILE, \fB\-\-manifest\-file\fR=\fI\,MANIFEST_FILE\/\fR
-Optional manifest file to use for this GITC client.
-.TP
-\fB\-c\fR GITC_CLIENT, \fB\-\-gitc\-client\fR=\fI\,GITC_CLIENT\/\fR
-Name of the gitc_client instance to create or modify.
-.SS Multi\-manifest:
-.TP
-\fB\-\-outer\-manifest\fR
-operate starting at the outermost manifest
-.TP
-\fB\-\-no\-outer\-manifest\fR
-do not operate on outer manifests
-.TP
-\fB\-\-this\-manifest\-only\fR
-only operate on this (sub)manifest
-.TP
-\fB\-\-no\-this\-manifest\-only\fR, \fB\-\-all\-manifests\fR
-operate on this manifest and its submanifests
-.PP
-Run `repo help gitc\-init` to view the detailed manual.
-.SH DETAILS
-.PP
-The 'repo gitc\-init' command is ran to initialize a new GITC client for use with
-the GITC file system.
-.PP
-This command will setup the client directory, initialize repo, just like repo
-init does, and then downloads the manifest collection and installs it in the
-\&.repo/directory of the GITC client.
-.PP
-Once this is done, a GITC manifest is generated by pulling the HEAD SHA for each
-project and generates the properly formatted XML file and installs it as
-\&.manifest in the GITC client directory.
-.PP
-The \fB\-c\fR argument is required to specify the GITC client name.
-.PP
-The optional \fB\-f\fR argument can be used to specify the manifest file to use for
-this GITC client.
--- a/man/repo-init.1
+++ b/man/repo-init.1
@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man.
-.TH REPO "1" "October 2022" "repo init" "Repo Manual"
+.TH REPO "1" "September 2024" "repo init" "Repo Manual"
 .SH NAME
 repo \- repo init - manual page for repo init
 .SH SYNOPSIS
@ -28,6 +28,11 @@ manifest repository location
 \fB\-b\fR REVISION, \fB\-\-manifest\-branch\fR=\fI\,REVISION\/\fR
 manifest branch or revision (use HEAD for default)
 .TP
+\fB\-\-manifest\-upstream\-branch\fR=\fI\,BRANCH\/\fR
+when a commit is provided to \fB\-\-manifest\-branch\fR, this
+is the name of the git ref in which the commit can be
+found
+.TP
 \fB\-m\fR NAME.xml, \fB\-\-manifest\-name\fR=\fI\,NAME\/\fR.xml
 initial manifest file
 .TP
@ -163,6 +168,10 @@ The optional \fB\-b\fR argument can be used to select the manifest branch to che
 and use. If no branch is specified, the remote's default branch is used. This is
 equivalent to using \fB\-b\fR HEAD.
 .PP
+The optional \fB\-\-manifest\-upstream\-branch\fR argument can be used when a commit is
+provided to \fB\-\-manifest\-branch\fR (or \fB\-b\fR), to specify the name of the git ref in
+which the commit can be found.
+.PP
 The optional \fB\-m\fR argument can be used to specify an alternate manifest to be
 used. If no manifest is specified, the manifest default.xml will be used.
 .PP
--- a/man/repo-manifest.1
+++ b/man/repo-manifest.1
@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man.
-.TH REPO "1" "October 2022" "repo manifest" "Repo Manual"
+.TH REPO "1" "April 2024" "repo manifest" "Repo Manual"
 .SH NAME
 repo \- repo manifest - manual page for repo manifest
 .SH SYNOPSIS
@ -194,8 +194,9 @@ CDATA #IMPLIED>
 <!ATTLIST extend\-project upstream CDATA #IMPLIED>
 .IP
 <!ELEMENT remove\-project EMPTY>
-<!ATTLIST remove\-project name  CDATA #REQUIRED>
-<!ATTLIST remove\-project optional  CDATA #IMPLIED>
+<!ATTLIST remove\-project name     CDATA #IMPLIED>
+<!ATTLIST remove\-project path     CDATA #IMPLIED>
+<!ATTLIST remove\-project optional CDATA #IMPLIED>
 .IP
 <!ELEMENT repo\-hooks EMPTY>
 <!ATTLIST repo\-hooks in\-project CDATA #REQUIRED>
@ -210,8 +211,9 @@ CDATA #IMPLIED>
 <!ATTLIST contactinfo bugurl  CDATA #REQUIRED>
 .IP
 <!ELEMENT include EMPTY>
-<!ATTLIST include name   CDATA #REQUIRED>
-<!ATTLIST include groups CDATA #IMPLIED>
+<!ATTLIST include name     CDATA #REQUIRED>
+<!ATTLIST include groups   CDATA #IMPLIED>
+<!ATTLIST include revision CDATA #IMPLIED>
 .PP
 ]>
 ```
@ -533,13 +535,24 @@ the repo client.
 .PP
 Element remove\-project
 .PP
-Deletes the named project from the internal manifest table, possibly allowing a
+Deletes a project from the internal manifest table, possibly allowing a
 subsequent project element in the same manifest file to replace the project with
 a different source.
 .PP
 This element is mostly useful in a local manifest file, where the user can
 remove a project, and possibly replace it with their own definition.
 .PP
+The project `name` or project `path` can be used to specify the remove target
+meaning one of them is required. If only name is specified, all projects with
+that name are removed.
+.PP
+If both name and path are specified, only projects with the same name and path
+are removed, meaning projects with the same name but in other locations are
+kept.
+.PP
+If only path is specified, a matching project is removed regardless of its name.
+Logic otherwise behaves like both are specified.
+.PP
 Attribute `optional`: Set to true to ignore remove\-project elements with no
 matching `project` element.
 .PP
@ -608,7 +621,10 @@ included manifest belong. This appends and recurses, meaning all projects in
 included manifests carry all parent include groups. Same syntax as the
 corresponding element of `project`.
 .PP
-Local Manifests 
+Attribute `revision`: Name of a Git branch (e.g. `main` or `refs/heads/main`)
+default to which all projects in the included manifest belong.
+.PP
+Local Manifests
 .PP
 Additional remotes and projects may be added through local manifest files stored
 in `$TOP_DIR/.repo/local_manifests/*.xml`.
--- a/man/repo-smartsync.1
+++ b/man/repo-smartsync.1
@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man.
-.TH REPO "1" "November 2022" "repo smartsync" "Repo Manual"
+.TH REPO "1" "September 2024" "repo smartsync" "Repo Manual"
 .SH NAME
 repo \- repo smartsync - manual page for repo smartsync
 .SH SYNOPSIS
@ -37,11 +37,20 @@ overwrite an existing git directory if it needs to
 point to a different object directory. WARNING: this
 may cause loss of data
 .TP
+\fB\-\-force\-checkout\fR
+force checkout even if it results in throwing away
+uncommitted modifications. WARNING: this may cause
+loss of data
+.TP
 \fB\-\-force\-remove\-dirty\fR
 force remove projects with uncommitted modifications
 if projects no longer exist in the manifest. WARNING:
 this may cause loss of data
 .TP
+\fB\-\-rebase\fR
+rebase local commits regardless of whether they are
+published
+.TP
 \fB\-l\fR, \fB\-\-local\-only\fR
 only update working tree, don't fetch
 .TP
--- a/man/repo-sync.1
+++ b/man/repo-sync.1
@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man.
-.TH REPO "1" "November 2022" "repo sync" "Repo Manual"
+.TH REPO "1" "September 2024" "repo sync" "Repo Manual"
 .SH NAME
 repo \- repo sync - manual page for repo sync
 .SH SYNOPSIS
@ -37,11 +37,20 @@ overwrite an existing git directory if it needs to
 point to a different object directory. WARNING: this
 may cause loss of data
 .TP
+\fB\-\-force\-checkout\fR
+force checkout even if it results in throwing away
+uncommitted modifications. WARNING: this may cause
+loss of data
+.TP
 \fB\-\-force\-remove\-dirty\fR
 force remove projects with uncommitted modifications
 if projects no longer exist in the manifest. WARNING:
 this may cause loss of data
 .TP
+\fB\-\-rebase\fR
+rebase local commits regardless of whether they are
+published
+.TP
 \fB\-l\fR, \fB\-\-local\-only\fR
 only update working tree, don't fetch
 .TP
@ -185,6 +194,11 @@ The \fB\-\-force\-sync\fR option can be used to overwrite existing git directori
 they have previously been linked to a different object directory. WARNING: This
 may cause data to be lost since refs may be removed when overwriting.
 .PP
+The \fB\-\-force\-checkout\fR option can be used to force git to switch revs even if the
+index or the working tree differs from HEAD, and if there are untracked files.
+WARNING: This may cause data to be lost since uncommitted changes may be
+removed.
+.PP
 The \fB\-\-force\-remove\-dirty\fR option can be used to remove previously used projects
 with uncommitted changes. WARNING: This may cause data to be lost since
 uncommitted changes may be removed with projects that no longer exist in the
--- a/man/repo-upload.1
+++ b/man/repo-upload.1
@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man.
-.TH REPO "1" "August 2022" "repo upload" "Repo Manual"
+.TH REPO "1" "June 2024" "repo upload" "Repo Manual"
 .SH NAME
 repo \- repo upload - manual page for repo upload
 .SH SYNOPSIS
@ -18,8 +18,11 @@ show this help message and exit
 number of jobs to run in parallel (default: based on
 number of CPU cores)
 .TP
-\fB\-t\fR
-send local branch name to Gerrit Code Review
+\fB\-t\fR, \fB\-\-topic\-branch\fR
+set the topic to the local branch name
+.TP
+\fB\-\-topic\fR=\fI\,TOPIC\/\fR
+set topic for the change
 .TP
 \fB\-\-hashtag\fR=\fI\,HASHTAGS\/\fR, \fB\-\-ht\fR=\fI\,HASHTAGS\/\fR
 add hashtags (comma delimited) to the review
@ -30,6 +33,9 @@ add local branch name as a hashtag
 \fB\-l\fR LABELS, \fB\-\-label\fR=\fI\,LABELS\/\fR
 add a label when uploading
 .TP
+\fB\-\-pd\fR=\fI\,PATCHSET_DESCRIPTION\/\fR, \fB\-\-patchset\-description\fR=\fI\,PATCHSET_DESCRIPTION\/\fR
+description for patchset
+.TP
 \fB\-\-re\fR=\fI\,REVIEWERS\/\fR, \fB\-\-reviewers\fR=\fI\,REVIEWERS\/\fR
 request reviews from these people
 .TP
@ -198,6 +204,12 @@ review.URL.uploadnotify:
 Control e\-mail notifications when uploading.
 https://gerrit\-review.googlesource.com/Documentation/user\-upload.html#notify
 .PP
+review.URL.uploadwarningthreshold:
+.PP
+Repo will warn you if you are attempting to upload a large number of commits in
+one or more branches. By default, the threshold is five commits. This option
+allows you to override the warning threshold to a different value.
+.PP
 References
 .PP
 Gerrit Code Review: https://www.gerritcodereview.com/
--- a/man/repo.1
+++ b/man/repo.1
@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man.
-.TH REPO "1" "June 2023" "repo" "Repo Manual"
+.TH REPO "1" "April 2024" "repo" "Repo Manual"
 .SH NAME
 repo \- repository management tool built on top of git
 .SH SYNOPSIS
@ -79,12 +79,6 @@ Download and checkout a change
 forall
 Run a shell command in each project
 .TP
-gitc\-delete
-Delete a GITC Client.
-.TP
-gitc\-init
-Initialize a GITC Client.
-.TP
 grep
 Print lines matching a pattern
 .TP
--- a/manifest_xml.py
+++ b/manifest_xml.py
@ -435,11 +435,6 @@ class XmlManifest:
        self.parent_groups = parent_groups
        self.default_groups = default_groups

-        if outer_client and self.isGitcClient:
-            raise ManifestParseError(
-                "Multi-manifest is incompatible with `gitc-init`"
-            )
-
        if submanifest_path and not outer_client:
            # If passing a submanifest_path, there must be an outer_client.
            raise ManifestParseError(f"Bad call to {self.__class__.__name__}")
@ -1450,6 +1445,7 @@ https://gerrit.googlesource.com/git-repo/+/HEAD/docs/manifest-format.md

        repo_hooks_project = None
        enabled_repo_hooks = None
+        failed_revision_changes = []
        for node in itertools.chain(*node_list):
            if node.nodeName == "project":
                project = self._ParseProject(node)
@ -1476,6 +1472,7 @@ https://gerrit.googlesource.com/git-repo/+/HEAD/docs/manifest-format.md
                    remote = self._get_remote(node)
                dest_branch = node.getAttribute("dest-branch")
                upstream = node.getAttribute("upstream")
+                base_revision = node.getAttribute("base-rev")

                named_projects = self._projects[name]
                if dest_path and not path and len(named_projects) > 1:
@ -1489,6 +1486,13 @@ https://gerrit.googlesource.com/git-repo/+/HEAD/docs/manifest-format.md
                    if groups:
                        p.groups.extend(groups)
                    if revision:
+                        if base_revision:
+                            if p.revisionExpr != base_revision:
+                                failed_revision_changes.append(
+                                    "extend-project name %s mismatch base "
+                                    "%s vs revision %s"
+                                    % (name, base_revision, p.revisionExpr)
+                                )
                        p.SetRevision(revision)

                    if remote_name:
@ -1563,6 +1567,7 @@ https://gerrit.googlesource.com/git-repo/+/HEAD/docs/manifest-format.md
            if node.nodeName == "remove-project":
                name = node.getAttribute("name")
                path = node.getAttribute("path")
+                base_revision = node.getAttribute("base-rev")

                # Name or path needed.
                if not name and not path:
@ -1576,6 +1581,13 @@ https://gerrit.googlesource.com/git-repo/+/HEAD/docs/manifest-format.md
                for projname, projects in list(self._projects.items()):
                    for p in projects:
                        if name == projname and not path:
+                            if base_revision:
+                                if p.revisionExpr != base_revision:
+                                    failed_revision_changes.append(
+                                        "remove-project name %s mismatch base "
+                                        "%s vs revision %s"
+                                        % (name, base_revision, p.revisionExpr)
+                                    )
                            del self._paths[p.relpath]
                            if not removed_project:
                                del self._projects[name]
@ -1583,6 +1595,17 @@ https://gerrit.googlesource.com/git-repo/+/HEAD/docs/manifest-format.md
                        elif path == p.relpath and (
                            name == projname or not name
                        ):
+                            if base_revision:
+                                if p.revisionExpr != base_revision:
+                                    failed_revision_changes.append(
+                                        "remove-project path %s mismatch base "
+                                        "%s vs revision %s"
+                                        % (
+                                            p.relpath,
+                                            base_revision,
+                                            p.revisionExpr,
+                                        )
+                                    )
                            self._projects[projname].remove(p)
                            del self._paths[p.relpath]
                            removed_project = p.name
@ -1602,6 +1625,13 @@ https://gerrit.googlesource.com/git-repo/+/HEAD/docs/manifest-format.md
                        "project: %s" % node.toxml()
                    )

+        if failed_revision_changes:
+            raise ManifestParseError(
+                "revision base check failed, rebase patches and update "
+                "base revs for: ",
+                failed_revision_changes,
+            )
+
        # Store repo hooks project information.
        if repo_hooks_project:
            # Store a reference to the Project.
@ -2290,7 +2320,6 @@ class RepoClient(XmlManifest):
            submanifest_path: The submanifest root relative to the repo root.
            **kwargs: Additional keyword arguments, passed to XmlManifest.
        """
-        self.isGitcClient = False
        submanifest_path = submanifest_path or ""
        if submanifest_path:
            self._CheckLocalPath(submanifest_path)
--- a/platform_utils.py
+++ b/platform_utils.py
@ -251,32 +251,3 @@ def readlink(path):
        return platform_utils_win32.readlink(_makelongpath(path))
    else:
        return os.readlink(path)
-
-
-def realpath(path):
-    """Return the canonical path of the specified filename, eliminating
-    any symbolic links encountered in the path.
-
-    Availability: Windows, Unix.
-    """
-    if isWindows():
-        current_path = os.path.abspath(path)
-        path_tail = []
-        for c in range(0, 100):  # Avoid cycles
-            if islink(current_path):
-                target = readlink(current_path)
-                current_path = os.path.join(
-                    os.path.dirname(current_path), target
-                )
-            else:
-                basename = os.path.basename(current_path)
-                if basename == "":
-                    path_tail.append(current_path)
-                    break
-                path_tail.append(basename)
-                current_path = os.path.dirname(current_path)
-        path_tail.reverse()
-        result = os.path.normpath(os.path.join(*path_tail))
-        return result
-    else:
-        return os.path.realpath(path)
--- a/progress.py
+++ b/progress.py
@ -100,6 +100,7 @@ class Progress:
        self._show = not delay
        self._units = units
        self._elide = elide and _TTY
+        self._quiet = quiet

        # Only show the active jobs section if we run more than one in parallel.
        self._show_jobs = False
@ -114,13 +115,7 @@ class Progress:
        )
        self._update_thread.daemon = True

-        # When quiet, never show any output.  It's a bit hacky, but reusing the
-        # existing logic that delays initial output keeps the rest of the class
-        # clean.  Basically we set the start time to years in the future.
-        if quiet:
-            self._show = False
-            self._start += 2**32
-        elif show_elapsed:
+        if not quiet and show_elapsed:
            self._update_thread.start()

    def _update_loop(self):
@ -160,7 +155,7 @@ class Progress:
            msg = self._last_msg
        self._last_msg = msg

-        if not _TTY or IsTraceToStderr():
+        if not _TTY or IsTraceToStderr() or self._quiet:
            return

        elapsed_sec = time.time() - self._start
@ -202,7 +197,7 @@ class Progress:

    def end(self):
        self._update_event.set()
-        if not _TTY or IsTraceToStderr() or not self._show:
+        if not _TTY or IsTraceToStderr() or self._quiet:
            return

        duration = duration_str(time.time() - self._start)
--- a/project.py
+++ b/project.py
@ -32,6 +32,7 @@ import urllib.parse

 from color import Coloring
 from error import DownloadError
+from error import GitAuthError
 from error import GitError
 from error import ManifestInvalidPathError
 from error import ManifestInvalidRevisionError
@ -145,7 +146,7 @@ def _ProjectHooks():
    """
    global _project_hook_list
    if _project_hook_list is None:
-        d = platform_utils.realpath(os.path.abspath(os.path.dirname(__file__)))
+        d = os.path.realpath(os.path.abspath(os.path.dirname(__file__)))
        d = os.path.join(d, "hooks")
        _project_hook_list = [
            os.path.join(d, x) for x in platform_utils.listdir(d)
@ -257,7 +258,7 @@ class ReviewableBranch:
        self,
        people,
        dryrun=False,
-        auto_topic=False,
+        topic=None,
        hashtags=(),
        labels=(),
        private=False,
@ -273,7 +274,7 @@ class ReviewableBranch:
            branch=self.name,
            people=people,
            dryrun=dryrun,
-            auto_topic=auto_topic,
+            topic=topic,
            hashtags=hashtags,
            labels=labels,
            private=private,
@ -727,12 +728,34 @@ class Project:
        return None

    def IsRebaseInProgress(self):
+        """Returns true if a rebase or "am" is in progress"""
+        # "rebase-apply" is used for "git rebase".
+        # "rebase-merge" is used for "git am".
        return (
            os.path.exists(self.work_git.GetDotgitPath("rebase-apply"))
            or os.path.exists(self.work_git.GetDotgitPath("rebase-merge"))
            or os.path.exists(os.path.join(self.worktree, ".dotest"))
        )

+    def IsCherryPickInProgress(self):
+        """Returns True if a cherry-pick is in progress."""
+        return os.path.exists(self.work_git.GetDotgitPath("CHERRY_PICK_HEAD"))
+
+    def _AbortRebase(self):
+        """Abort ongoing rebase, cherry-pick or patch apply (am).
+
+        If no rebase, cherry-pick or patch apply was in progress, this method
+        ignores the status and continues.
+        """
+
+        def _git(*args):
+            # Ignore return code, in case there was no rebase in progress.
+            GitCommand(self, args, log_as_error=False).Wait()
+
+        _git("cherry-pick", "--abort")
+        _git("rebase", "--abort")
+        _git("am", "--abort")
+
    def IsDirty(self, consider_untracked=True):
        """Is the working directory modified in some way?"""
        self.work_git.update_index(
@ -1082,7 +1105,7 @@ class Project:
        branch=None,
        people=([], []),
        dryrun=False,
-        auto_topic=False,
+        topic=None,
        hashtags=(),
        labels=(),
        private=False,
@ -1145,8 +1168,7 @@ class Project:
        # This stops git from pushing all reachable annotated tags when
        # push.followTags is configured. Gerrit does not accept any tags
        # pushed to a CL.
-        if git_require((1, 8, 3)):
-            cmd.append("--no-follow-tags")
+        cmd.append("--no-follow-tags")

        for push_option in push_options or []:
            cmd.append("-o")
@ -1159,8 +1181,8 @@ class Project:

        ref_spec = f"{R_HEADS + branch.name}:refs/for/{dest_branch}"
        opts = []
-        if auto_topic:
-            opts += ["topic=" + branch.name]
+        if topic is not None:
+            opts += [f"topic={topic}"]
        opts += ["t=%s" % p for p in hashtags]
        # NB: No need to encode labels as they've been validated above.
        opts += ["l=%s" % p for p in labels]
@ -1462,8 +1484,6 @@ class Project:
        self._InitHooks()

    def _CopyAndLinkFiles(self):
-        if self.client.isGitcClient:
-            return
        for copyfile in self.copyfiles:
            copyfile._Copy()
        for linkfile in self.linkfiles:
@ -1516,6 +1536,7 @@ class Project:
        syncbuf,
        force_sync=False,
        force_checkout=False,
+        force_rebase=False,
        submodules=False,
        errors=None,
        verbose=False,
@ -1586,7 +1607,15 @@ class Project:
        if branch is None or syncbuf.detach_head:
            # Currently on a detached HEAD.  The user is assumed to
            # not have any local modifications worth worrying about.
-            if self.IsRebaseInProgress():
+            rebase_in_progress = (
+                self.IsRebaseInProgress() or self.IsCherryPickInProgress()
+            )
+            if rebase_in_progress and force_checkout:
+                self._AbortRebase()
+                rebase_in_progress = (
+                    self.IsRebaseInProgress() or self.IsCherryPickInProgress()
+                )
+            if rebase_in_progress:
                fail(_PriorSyncFailedError(project=self.name))
                return

@ -1653,18 +1682,21 @@ class Project:
        if pub:
            not_merged = self._revlist(not_rev(revid), pub)
            if not_merged:
-                if upstream_gain:
+                if upstream_gain and not force_rebase:
                    # The user has published this branch and some of those
                    # commits are not yet merged upstream.  We do not want
                    # to rewrite the published commits so we punt.
                    fail(
                        LocalSyncFail(
                            "branch %s is published (but not merged) and is "
-                            "now %d commits behind"
+                            "now %d commits behind. Fix this manually or rerun "
+                            "with the --rebase option to force a rebase."
                            % (branch.name, len(upstream_gain)),
                            project=self.name,
                        )
                    )
+                    return
+                syncbuf.later1(self, _doff, not verbose)
                return
            elif pub == head:
                # All published commits are merged, and thus we are a
@ -1826,7 +1858,7 @@ class Project:
        # remove because it will recursively delete projects -- we handle that
        # ourselves below.  https://crbug.com/git/48
        if self.use_git_worktrees:
-            needle = platform_utils.realpath(self.gitdir)
+            needle = os.path.realpath(self.gitdir)
            # Find the git worktree commondir under .repo/worktrees/.
            output = self.bare_git.worktree("list", "--porcelain").splitlines()[
                0
@ -1840,7 +1872,7 @@ class Project:
                with open(gitdir) as fp:
                    relpath = fp.read().strip()
                # Resolve the checkout path and see if it matches this project.
-                fullpath = platform_utils.realpath(
+                fullpath = os.path.realpath(
                    os.path.join(configs, name, relpath)
                )
                if fullpath == needle:
@ -2264,7 +2296,9 @@ class Project:

        try:
            rev = self.GetRevisionId()
-        except GitError:
+        except (GitError, ManifestInvalidRevisionError):
+            # The git repo may be outdated (i.e. not fetched yet) and querying
+            # its submodules using the revision may not work; so return here.
            return []
        return get_submodules(self.gitdir, rev)

@ -2364,26 +2398,25 @@ class Project:
        try:
            # if revision (sha or tag) is not present then following function
            # throws an error.
+            revs = [f"{self.revisionExpr}^0"]
+            upstream_rev = None
+            if self.upstream:
+                upstream_rev = self.GetRemote().ToLocal(self.upstream)
+                revs.append(upstream_rev)
+
            self.bare_git.rev_list(
                "-1",
                "--missing=allow-any",
-                "%s^0" % self.revisionExpr,
+                *revs,
                "--",
                log_as_error=False,
            )
+
            if self.upstream:
-                rev = self.GetRemote().ToLocal(self.upstream)
-                self.bare_git.rev_list(
-                    "-1",
-                    "--missing=allow-any",
-                    "%s^0" % rev,
-                    "--",
-                    log_as_error=False,
-                )
                self.bare_git.merge_base(
                    "--is-ancestor",
                    self.revisionExpr,
-                    rev,
+                    upstream_rev,
                    log_as_error=False,
                )
            return True
@ -2567,12 +2600,7 @@ class Project:
            branch = None
        else:
            branch = self.revisionExpr
-        if (
-            not self.manifest.IsMirror
-            and is_sha1
-            and depth
-            and git_require((1, 8, 3))
-        ):
+        if not self.manifest.IsMirror and is_sha1 and depth:
            # 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)
@ -2635,6 +2663,20 @@ class Project:
                # Fallthru to sleep+retry logic at the bottom.
                pass

+            # TODO(b/360889369#comment24): git may gc commits incorrectly.
+            # Until the root cause is fixed, retry fetch with --refetch which
+            # will bring the repository into a good state.
+            elif gitcmd.stdout and (
+                "could not parse commit" in gitcmd.stdout
+                or "unable to parse commit" in gitcmd.stdout
+            ):
+                cmd.insert(1, "--refetch")
+                print(
+                    "could not parse commit error, retrying with refetch",
+                    file=output_redir,
+                )
+                continue
+
            # Try to prune remote branches once in case there are conflicts.
            # For example, if the remote had refs/heads/upstream, but deleted
            # that and now has refs/heads/upstream/foo.
@ -2660,6 +2702,33 @@ class Project:
                )
                # Continue right away so we don't sleep as we shouldn't need to.
                continue
+            elif (
+                ret == 128
+                and gitcmd.stdout
+                and "fatal: could not read Username" in gitcmd.stdout
+            ):
+                # User needs to be authenticated, and Git wants to prompt for
+                # username and password.
+                print(
+                    "git requires authentication, but repo cannot perform "
+                    "interactive authentication. Check git credentials.",
+                    file=output_redir,
+                )
+                break
+            elif (
+                ret == 128
+                and gitcmd.stdout
+                and "remote helper 'sso' aborted session" in gitcmd.stdout
+            ):
+                # User needs to be authenticated, and Git wants to prompt for
+                # username and password.
+                print(
+                    "git requires authentication, but repo cannot perform "
+                    "interactive authentication.",
+                    file=output_redir,
+                )
+                raise GitAuthError(gitcmd.stdout)
+                break
            elif current_branch_only and is_sha1 and ret == 128:
                # Exit code 128 means "couldn't find the ref you asked for"; if
                # we're in sha1 mode, we just tried sync'ing from the upstream
@ -2784,6 +2853,8 @@ class Project:
    def _FetchBundle(self, srcUrl, tmpPath, dstPath, quiet, verbose):
        platform_utils.remove(dstPath, missing_ok=True)

+        # We do not use curl's --retry option since it generally doesn't
+        # actually retry anything; code 18 for example, it will not retry on.
        cmd = ["curl", "--fail", "--output", tmpPath, "--netrc", "--location"]
        if quiet:
            cmd += ["--silent", "--show-error"]
@ -2820,11 +2891,18 @@ class Project:
            (output, _) = proc.communicate()
            curlret = proc.returncode

-            if curlret == 22:
+            if curlret in (22, 35, 56, 92):
+                # We use --fail so curl exits with unique status.
                # From curl man page:
-                # 22: HTTP page not retrieved. The requested url was not found
-                # or returned another error with the HTTP error code being 400
-                # or above. This return code only appears if -f, --fail is used.
+                # 22: HTTP page not retrieved.  The requested url was not found
+                #     or returned another error with the HTTP error code being
+                #     400 or above.
+                # 35: SSL connect error.  The SSL handshaking failed.  This can
+                #     be thrown by Google storage sometimes.
+                # 56: Failure in receiving network data.  This shows up with
+                #     HTTP/404 on Google storage.
+                # 92: Stream error in HTTP/2 framing layer.  Basically the same
+                #     as 22 -- Google storage sometimes throws 500's.
                if verbose:
                    print(
                        "%s: Unable to retrieve clone.bundle; ignoring."
@ -2975,14 +3053,12 @@ class Project:
                            "Retrying clone after deleting %s", self.gitdir
                        )
                        try:
-                            platform_utils.rmtree(
-                                platform_utils.realpath(self.gitdir)
-                            )
+                            platform_utils.rmtree(os.path.realpath(self.gitdir))
                            if self.worktree and os.path.exists(
-                                platform_utils.realpath(self.worktree)
+                                os.path.realpath(self.worktree)
                            ):
                                platform_utils.rmtree(
-                                    platform_utils.realpath(self.worktree)
+                                    os.path.realpath(self.worktree)
                                )
                            return self._InitGitDir(
                                mirror_git=mirror_git,
@ -3068,7 +3144,7 @@ class Project:
            self._InitHooks(quiet=quiet)

    def _InitHooks(self, quiet=False):
-        hooks = platform_utils.realpath(os.path.join(self.objdir, "hooks"))
+        hooks = os.path.realpath(os.path.join(self.objdir, "hooks"))
        if not os.path.exists(hooks):
            os.makedirs(hooks)

@ -3211,9 +3287,9 @@ class Project:
            dst_path = os.path.join(destdir, name)
            src_path = os.path.join(srcdir, name)

-            dst = platform_utils.realpath(dst_path)
+            dst = os.path.realpath(dst_path)
            if os.path.lexists(dst):
-                src = platform_utils.realpath(src_path)
+                src = os.path.realpath(src_path)
                # Fail if the links are pointing to the wrong place.
                if src != dst:
                    logger.error(
@ -3249,10 +3325,10 @@ class Project:
        if copy_all:
            to_copy = platform_utils.listdir(gitdir)

-        dotgit = platform_utils.realpath(dotgit)
+        dotgit = os.path.realpath(dotgit)
        for name in set(to_copy).union(to_symlink):
            try:
-                src = platform_utils.realpath(os.path.join(gitdir, name))
+                src = os.path.realpath(os.path.join(gitdir, name))
                dst = os.path.join(dotgit, name)

                if os.path.lexists(dst):
@ -3299,24 +3375,29 @@ class Project:
            setting = fp.read()
            assert setting.startswith("gitdir:")
            git_worktree_path = setting.split(":", 1)[1].strip()
-        # Some platforms (e.g. Windows) won't let us update dotgit in situ
-        # because of file permissions.  Delete it and recreate it from scratch
-        # to avoid.
-        platform_utils.remove(dotgit)
-        # Use relative path from checkout->worktree & maintain Unix line endings
-        # on all OS's to match git behavior.
-        with open(dotgit, "w", newline="\n") as fp:
-            print(
-                "gitdir:",
-                os.path.relpath(git_worktree_path, self.worktree),
-                file=fp,
-            )
-        # Use relative path from worktree->checkout & maintain Unix line endings
-        # on all OS's to match git behavior.
-        with open(
-            os.path.join(git_worktree_path, "gitdir"), "w", newline="\n"
-        ) as fp:
-            print(os.path.relpath(dotgit, git_worktree_path), file=fp)
+
+        # `gitdir` maybe be either relative or absolute depending on the
+        # behavior of the local copy of git, so only convert the path to
+        # relative if it needs to be converted.
+        if os.path.isabs(git_worktree_path):
+            # Some platforms (e.g. Windows) won't let us update dotgit in situ
+            # because of file permissions.  Delete it and recreate it from
+            # scratch to avoid.
+            platform_utils.remove(dotgit)
+            # Use relative path from checkout->worktree & maintain Unix line
+            # endings on all OS's to match git behavior.
+            with open(dotgit, "w", newline="\n") as fp:
+                print(
+                    "gitdir:",
+                    os.path.relpath(git_worktree_path, self.worktree),
+                    file=fp,
+                )
+            # Use relative path from worktree->checkout & maintain Unix line
+            # endings on all OS's to match git behavior.
+            with open(
+                os.path.join(git_worktree_path, "gitdir"), "w", newline="\n"
+            ) as fp:
+                print(os.path.relpath(dotgit, git_worktree_path), file=fp)

        self._InitMRef()

@ -3349,9 +3430,7 @@ class Project:
        else:
            if not init_dotgit:
                # See if the project has changed.
-                if platform_utils.realpath(
-                    self.gitdir
-                ) != platform_utils.realpath(dotgit):
+                if os.path.realpath(self.gitdir) != os.path.realpath(dotgit):
                    platform_utils.remove(dotgit)

            if init_dotgit or not os.path.exists(dotgit):
--- a/release/update-hooks
+++ b/release/update-hooks
@ -0,0 +1,143 @@
+#!/usr/bin/env python3
+# Copyright (C) 2024 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.
+
+"""Helper tool for updating hooks from their various upstreams."""
+
+import argparse
+import base64
+import json
+from pathlib import Path
+import sys
+from typing import List, Optional
+import urllib.request
+
+
+assert sys.version_info >= (3, 8), "Python 3.8+ required"
+
+
+TOPDIR = Path(__file__).resolve().parent.parent
+HOOKS_DIR = TOPDIR / "hooks"
+
+
+def update_hook_commit_msg() -> None:
+    """Update commit-msg hook from Gerrit."""
+    hook = HOOKS_DIR / "commit-msg"
+    print(
+        f"{hook.name}: Updating from https://gerrit.googlesource.com/gerrit/"
+        "+/HEAD/resources/com/google/gerrit/server/tools/root/hooks/commit-msg"
+    )
+
+    # Get the current commit.
+    url = "https://gerrit.googlesource.com/gerrit/+/HEAD?format=JSON"
+    with urllib.request.urlopen(url) as fp:
+        data = fp.read()
+    # Discard the xss protection.
+    data = data.split(b"\n", 1)[1]
+    data = json.loads(data)
+    commit = data["commit"]
+
+    # Fetch the data for that commit.
+    url = (
+        f"https://gerrit.googlesource.com/gerrit/+/{commit}/"
+        "resources/com/google/gerrit/server/tools/root/hooks/commit-msg"
+    )
+    with urllib.request.urlopen(f"{url}?format=TEXT") as fp:
+        data = fp.read()
+
+    # gitiles base64 encodes text data.
+    data = base64.b64decode(data)
+
+    # Inject header into the hook.
+    lines = data.split(b"\n")
+    lines = (
+        lines[:1]
+        + [
+            b"# DO NOT EDIT THIS FILE",
+            (
+                b"# All updates should be sent upstream: "
+                b"https://gerrit.googlesource.com/gerrit/"
+            ),
+            f"# This is synced from commit: {commit}".encode("utf-8"),
+            b"# DO NOT EDIT THIS FILE",
+        ]
+        + lines[1:]
+    )
+    data = b"\n".join(lines)
+
+    # Update the hook.
+    hook.write_bytes(data)
+    hook.chmod(0o755)
+
+
+def update_hook_pre_auto_gc() -> None:
+    """Update pre-auto-gc hook from git."""
+    hook = HOOKS_DIR / "pre-auto-gc"
+    print(
+        f"{hook.name}: Updating from https://github.com/git/git/"
+        "HEAD/contrib/hooks/pre-auto-gc-battery"
+    )
+
+    # Get the current commit.
+    headers = {
+        "Accept": "application/vnd.github+json",
+        "X-GitHub-Api-Version": "2022-11-28",
+    }
+    url = "https://api.github.com/repos/git/git/git/refs/heads/master"
+    req = urllib.request.Request(url, headers=headers)
+    with urllib.request.urlopen(req) as fp:
+        data = fp.read()
+    data = json.loads(data)
+
+    # Fetch the data for that commit.
+    commit = data["object"]["sha"]
+    url = (
+        f"https://raw.githubusercontent.com/git/git/{commit}/"
+        "contrib/hooks/pre-auto-gc-battery"
+    )
+    with urllib.request.urlopen(url) as fp:
+        data = fp.read()
+
+    # Inject header into the hook.
+    lines = data.split(b"\n")
+    lines = (
+        lines[:1]
+        + [
+            b"# DO NOT EDIT THIS FILE",
+            (
+                b"# All updates should be sent upstream: "
+                b"https://github.com/git/git/"
+            ),
+            f"# This is synced from commit: {commit}".encode("utf-8"),
+            b"# DO NOT EDIT THIS FILE",
+        ]
+        + lines[1:]
+    )
+    data = b"\n".join(lines)
+
+    # Update the hook.
+    hook.write_bytes(data)
+    hook.chmod(0o755)
+
+
+def main(argv: Optional[List[str]] = None) -> Optional[int]:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.parse_args(argv)
+
+    update_hook_commit_msg()
+    update_hook_pre_auto_gc()
+
+
+if __name__ == "__main__":
+    sys.exit(main(sys.argv[1:]))
--- a/21
+++ b/21
@ -124,7 +124,7 @@ if not REPO_REV:
 BUG_URL = "https://issues.gerritcodereview.com/issues/new?component=1370071"

 # increment this whenever we make important changes to this script
-VERSION = (2, 45)
+VERSION = (2, 48)

 # increment this if the MAINTAINER_KEYS block is modified
 KEYRING_VERSION = (2, 3)
@ -210,7 +210,6 @@ GIT = "git"  # our git command
 # NB: The version of git that the repo launcher requires may be much older than
 # the version of git that the main repo source tree requires.  Keeping this at
 # an older version also makes it easier for users to upgrade/rollback as needed.
-# See requirements.json for versions.
 MIN_GIT_VERSION = (1, 7, 9)  # minimum supported git version
 repodir = ".repo"  # name of repo's private directory
 S_repo = "repo"  # special repo repository
@ -283,6 +282,12 @@ def InitParser(parser):
        metavar="REVISION",
        help="manifest branch or revision (use HEAD for default)",
    )
+    group.add_option(
+        "--manifest-upstream-branch",
+        help="when a commit is provided to --manifest-branch, this "
+        "is the name of the git ref in which the commit can be found",
+        metavar="BRANCH",
+    )
    group.add_option(
        "-m",
        "--manifest-name",
@ -1237,13 +1242,13 @@ class Requirements:

        return cls(json_data)

-    def _get_soft_ver(self, pkg):
+    def get_soft_ver(self, pkg):
        """Return the soft version for |pkg| if it exists."""
-        return self.requirements.get(pkg, {}).get("soft", ())
+        return tuple(self.requirements.get(pkg, {}).get("soft", ()))

-    def _get_hard_ver(self, pkg):
+    def get_hard_ver(self, pkg):
        """Return the hard version for |pkg| if it exists."""
-        return self.requirements.get(pkg, {}).get("hard", ())
+        return tuple(self.requirements.get(pkg, {}).get("hard", ()))

    @staticmethod
    def _format_ver(ver):
@ -1253,8 +1258,8 @@ class Requirements:
    def assert_ver(self, pkg, curr_ver):
        """Verify |pkg|'s |curr_ver| is new enough."""
        curr_ver = tuple(curr_ver)
-        soft_ver = tuple(self._get_soft_ver(pkg))
-        hard_ver = tuple(self._get_hard_ver(pkg))
+        soft_ver = tuple(self.get_soft_ver(pkg))
+        hard_ver = tuple(self.get_hard_ver(pkg))
        if curr_ver < hard_ver:
            print(
                f'repo: error: Your version of "{pkg}" '
--- a/repo_logging.py
+++ b/repo_logging.py
@ -39,8 +39,8 @@ class _LogColoring(Coloring):

    def __init__(self, config):
        super().__init__(config, "logs")
-        self.error = self.colorer("error", fg="red")
-        self.warning = self.colorer("warn", fg="yellow")
+        self.error = self.nofmt_colorer("error", fg="red")
+        self.warning = self.nofmt_colorer("warn", fg="yellow")
        self.levelMap = {
            "WARNING": self.warning,
            "ERROR": self.error,
--- a/requirements.json
+++ b/requirements.json
@ -46,8 +46,6 @@

  # Supported git versions.
  #
-  # git-1.7.9 is in Ubuntu Precise.
-  # git-1.7.10 is in Debian Wheezy.
  # git-1.9.1 is in Ubuntu Trusty.
  # git-2.1.4 is in Debian Jessie.
  # git-2.7.4 is in Ubuntu Xenial.
@ -55,7 +53,7 @@
  # git-2.17.0 is in Ubuntu Bionic.
  # git-2.20.1 is in Debian Buster.
  "git": {
-    "hard": [1, 7, 9],
+    "hard": [1, 9, 1],
    "soft": [2, 7, 4]
  }
 }
--- a/1
+++ b/1
@ -32,6 +32,7 @@ def run_black():
    extra_programs = [
        "repo",
        "run_tests",
+        "release/update-hooks",
        "release/update-manpages",
    ]
    return subprocess.run(
--- a/ssh.py
+++ b/ssh.py
@ -24,6 +24,7 @@ import sys
 import tempfile
 import time

+from git_command import git
 import platform_utils
 from repo_trace import Trace

@ -211,7 +212,33 @@ class ProxyManager:
                # and print to the log there.
                pass

-        command = command_base[:1] + ["-M", "-N"] + command_base[1:]
+        # Git protocol V2 is a new feature in git 2.18.0, made default in
+        # git 2.26.0
+        # It is faster and more efficient than V1.
+        # To enable it when using SSH, the environment variable GIT_PROTOCOL
+        # must be set in the SSH side channel when establishing the connection
+        # to the git server.
+        # See https://git-scm.com/docs/protocol-v2#_ssh_and_file_transport
+        # Normally git does this by itself. But here, where the SSH connection
+        # is established manually over ControlMaster via the repo-tool, it must
+        # be passed in explicitly instead.
+        # Based on https://git-scm.com/docs/gitprotocol-pack#_extra_parameters,
+        # GIT_PROTOCOL is considered an "Extra Parameter" and must be ignored
+        # by servers that do not understand it. This means that it is safe to
+        # set it even when connecting to older servers.
+        # It should also be safe to set the environment variable for older
+        # local git versions, since it is only part of the ssh side channel.
+        git_protocol_version = _get_git_protocol_version()
+        ssh_git_protocol_args = [
+            "-o",
+            f"SetEnv GIT_PROTOCOL=version={git_protocol_version}",
+        ]
+
+        command = (
+            command_base[:1]
+            + ["-M", "-N", *ssh_git_protocol_args]
+            + command_base[1:]
+        )
        p = None
        try:
            with Trace("Call to ssh: %s", " ".join(command)):
@ -293,3 +320,32 @@ class ProxyManager:
                tempfile.mkdtemp("", "ssh-", tmp_dir), "master-" + tokens
            )
        return self._sock_path
+
+
+@functools.lru_cache(maxsize=1)
+def _get_git_protocol_version() -> str:
+    """Return the git protocol version.
+
+    The version is found by first reading the global git config.
+    If no git config for protocol version exists, try to deduce the default
+    protocol version based on the git version.
+
+    See https://git-scm.com/docs/gitprotocol-v2 for details.
+    """
+    try:
+        return subprocess.check_output(
+            ["git", "config", "--get", "--global", "protocol.version"],
+            encoding="utf-8",
+            stderr=subprocess.PIPE,
+        ).strip()
+    except subprocess.CalledProcessError as e:
+        if e.returncode == 1:
+            # Exit code 1 means that the git config key was not found.
+            # Try to imitate the defaults that git would have used.
+            git_version = git.version_tuple()
+            if git_version >= (2, 26, 0):
+                # Since git version 2.26, protocol v2 is the default.
+                return "2"
+            return "1"
+        # Other exit codes indicate error with reading the config.
+        raise
--- a/subcmds/abandon.py
+++ b/subcmds/abandon.py
@ -70,8 +70,10 @@ It is equivalent to "git branch -D <branchname>".
        else:
            args.insert(0, "'All local branches'")

-    def _ExecuteOne(self, all_branches, nb, project):
+    @classmethod
+    def _ExecuteOne(cls, all_branches, nb, project_idx):
        """Abandon one project."""
+        project = cls.get_parallel_context()["projects"][project_idx]
        if all_branches:
            branches = project.GetBranches()
        else:
@ -89,7 +91,7 @@ It is equivalent to "git branch -D <branchname>".
            if status is not None:
                ret[name] = status

-        return (ret, project, errors)
+        return (ret, project_idx, errors)

    def Execute(self, opt, args):
        nb = args[0].split()
@ -102,7 +104,8 @@ It is equivalent to "git branch -D <branchname>".
        _RelPath = lambda p: p.RelPath(local=opt.this_manifest_only)

        def _ProcessResults(_pool, pm, states):
-            for results, project, errors in states:
+            for results, project_idx, errors in states:
+                project = all_projects[project_idx]
                for branch, status in results.items():
                    if status:
                        success[branch].append(project)
@ -111,15 +114,18 @@ It is equivalent to "git branch -D <branchname>".
                aggregate_errors.extend(errors)
                pm.update(msg="")

-        self.ExecuteInParallel(
-            opt.jobs,
-            functools.partial(self._ExecuteOne, opt.all, nb),
-            all_projects,
-            callback=_ProcessResults,
-            output=Progress(
-                f"Abandon {nb}", len(all_projects), quiet=opt.quiet
-            ),
-        )
+        with self.ParallelContext():
+            self.get_parallel_context()["projects"] = all_projects
+            self.ExecuteInParallel(
+                opt.jobs,
+                functools.partial(self._ExecuteOne, opt.all, nb),
+                range(len(all_projects)),
+                callback=_ProcessResults,
+                output=Progress(
+                    f"Abandon {nb}", len(all_projects), quiet=opt.quiet
+                ),
+                chunksize=1,
+            )

        width = max(
            itertools.chain(
--- a/subcmds/branches.py
+++ b/subcmds/branches.py
@ -98,6 +98,22 @@ is shown, then the branch appears in all projects.
 """
    PARALLEL_JOBS = DEFAULT_LOCAL_JOBS

+    @classmethod
+    def _ExpandProjectToBranches(cls, project_idx):
+        """Expands a project into a list of branch names & associated info.
+
+        Args:
+            project_idx: project.Project index
+
+        Returns:
+            List[Tuple[str, git_config.Branch, int]]
+        """
+        branches = []
+        project = cls.get_parallel_context()["projects"][project_idx]
+        for name, b in project.GetBranches().items():
+            branches.append((name, b, project_idx))
+        return branches
+
    def Execute(self, opt, args):
        projects = self.GetProjects(
            args, all_manifests=not opt.this_manifest_only
@ -107,17 +123,20 @@ is shown, then the branch appears in all projects.
        project_cnt = len(projects)

        def _ProcessResults(_pool, _output, results):
-            for name, b in itertools.chain.from_iterable(results):
+            for name, b, project_idx in itertools.chain.from_iterable(results):
+                b.project = projects[project_idx]
                if name not in all_branches:
                    all_branches[name] = BranchInfo(name)
                all_branches[name].add(b)

-        self.ExecuteInParallel(
-            opt.jobs,
-            expand_project_to_branches,
-            projects,
-            callback=_ProcessResults,
-        )
+        with self.ParallelContext():
+            self.get_parallel_context()["projects"] = projects
+            self.ExecuteInParallel(
+                opt.jobs,
+                self._ExpandProjectToBranches,
+                range(len(projects)),
+                callback=_ProcessResults,
+            )

        names = sorted(all_branches)

@ -191,19 +210,3 @@ is shown, then the branch appears in all projects.
            else:
                out.write(" in all projects")
            out.nl()
-
-
-def expand_project_to_branches(project):
-    """Expands a project into a list of branch names & associated information.
-
-    Args:
-        project: project.Project
-
-    Returns:
-        List[Tuple[str, git_config.Branch]]
-    """
-    branches = []
-    for name, b in project.GetBranches().items():
-        b.project = project
-        branches.append((name, b))
-    return branches
--- a/subcmds/checkout.py
+++ b/subcmds/checkout.py
@ -20,7 +20,6 @@ from command import DEFAULT_LOCAL_JOBS
 from error import GitError
 from error import RepoExitError
 from progress import Progress
-from project import Project
 from repo_logging import RepoLogger


@ -30,7 +29,7 @@ logger = RepoLogger(__file__)
 class CheckoutBranchResult(NamedTuple):
    # Whether the Project is on the branch (i.e. branch exists and no errors)
    result: bool
-    project: Project
+    project_idx: int
    error: Exception


@ -62,15 +61,17 @@ The command is equivalent to:
        if not args:
            self.Usage()

-    def _ExecuteOne(self, nb, project):
+    @classmethod
+    def _ExecuteOne(cls, nb, project_idx):
        """Checkout one project."""
        error = None
        result = None
+        project = cls.get_parallel_context()["projects"][project_idx]
        try:
            result = project.CheckoutBranch(nb)
        except GitError as e:
            error = e
-        return CheckoutBranchResult(result, project, error)
+        return CheckoutBranchResult(result, project_idx, error)

    def Execute(self, opt, args):
        nb = args[0]
@ -83,22 +84,25 @@ The command is equivalent to:

        def _ProcessResults(_pool, pm, results):
            for result in results:
+                project = all_projects[result.project_idx]
                if result.error is not None:
                    err.append(result.error)
-                    err_projects.append(result.project)
+                    err_projects.append(project)
                elif result.result:
-                    success.append(result.project)
+                    success.append(project)
                pm.update(msg="")

-        self.ExecuteInParallel(
-            opt.jobs,
-            functools.partial(self._ExecuteOne, nb),
-            all_projects,
-            callback=_ProcessResults,
-            output=Progress(
-                f"Checkout {nb}", len(all_projects), quiet=opt.quiet
-            ),
-        )
+        with self.ParallelContext():
+            self.get_parallel_context()["projects"] = all_projects
+            self.ExecuteInParallel(
+                opt.jobs,
+                functools.partial(self._ExecuteOne, nb),
+                range(len(all_projects)),
+                callback=_ProcessResults,
+                output=Progress(
+                    f"Checkout {nb}", len(all_projects), quiet=opt.quiet
+                ),
+            )

        if err_projects:
            for p in err_projects:
--- a/subcmds/diff.py
+++ b/subcmds/diff.py
@ -40,7 +40,8 @@ to the Unix 'patch' command.
            help="paths are relative to the repository root",
        )

-    def _ExecuteOne(self, absolute, local, project):
+    @classmethod
+    def _ExecuteOne(cls, absolute, local, project_idx):
        """Obtains the diff for a specific project.

        Args:
@ -48,12 +49,13 @@ to the Unix 'patch' command.
            local: a boolean, if True, the path is relative to the local
                (sub)manifest.  If false, the path is relative to the outermost
                manifest.
-            project: Project to get status of.
+            project_idx: Project index to get status of.

        Returns:
            The status of the project.
        """
        buf = io.StringIO()
+        project = cls.get_parallel_context()["projects"][project_idx]
        ret = project.PrintWorkTreeDiff(absolute, output_redir=buf, local=local)
        return (ret, buf.getvalue())

@ -71,12 +73,15 @@ to the Unix 'patch' command.
                    ret = 1
            return ret

-        return self.ExecuteInParallel(
-            opt.jobs,
-            functools.partial(
-                self._ExecuteOne, opt.absolute, opt.this_manifest_only
-            ),
-            all_projects,
-            callback=_ProcessResults,
-            ordered=True,
-        )
+        with self.ParallelContext():
+            self.get_parallel_context()["projects"] = all_projects
+            return self.ExecuteInParallel(
+                opt.jobs,
+                functools.partial(
+                    self._ExecuteOne, opt.absolute, opt.this_manifest_only
+                ),
+                range(len(all_projects)),
+                callback=_ProcessResults,
+                ordered=True,
+                chunksize=1,
+            )
--- a/subcmds/forall.py
+++ b/subcmds/forall.py
@ -15,7 +15,6 @@
 import errno
 import functools
 import io
-import multiprocessing
 import os
 import re
 import signal
@ -26,7 +25,6 @@ from color import Coloring
 from command import Command
 from command import DEFAULT_LOCAL_JOBS
 from command import MirrorSafeCommand
-from command import WORKER_BATCH_SIZE
 from error import ManifestInvalidRevisionError
 from repo_logging import RepoLogger

@ -241,7 +239,6 @@ without iterating through the remaining projects.
                    cmd.insert(cmd.index(cn) + 1, "--color")

        mirror = self.manifest.IsMirror
-        rc = 0

        smart_sync_manifest_name = "smart_sync_override.xml"
        smart_sync_manifest_path = os.path.join(
@ -264,35 +261,44 @@ without iterating through the remaining projects.

        os.environ["REPO_COUNT"] = str(len(projects))

+        def _ProcessResults(_pool, _output, results):
+            rc = 0
+            first = True
+            for r, output in results:
+                if output:
+                    if first:
+                        first = False
+                    elif opt.project_header:
+                        print()
+                    # To simplify the DoWorkWrapper, take care of automatic
+                    # newlines.
+                    end = "\n"
+                    if output[-1] == "\n":
+                        end = ""
+                    print(output, end=end)
+                rc = rc or r
+                if r != 0 and opt.abort_on_errors:
+                    raise Exception("Aborting due to previous error")
+            return rc
+
        try:
            config = self.manifest.manifestProject.config
-            with multiprocessing.Pool(opt.jobs, InitWorker) as pool:
-                results_it = pool.imap(
+            with self.ParallelContext():
+                self.get_parallel_context()["projects"] = projects
+                rc = self.ExecuteInParallel(
+                    opt.jobs,
                    functools.partial(
-                        DoWorkWrapper, mirror, opt, cmd, shell, config
+                        self.DoWorkWrapper, mirror, opt, cmd, shell, config
                    ),
-                    enumerate(projects),
-                    chunksize=WORKER_BATCH_SIZE,
+                    range(len(projects)),
+                    callback=_ProcessResults,
+                    ordered=True,
+                    initializer=self.InitWorker,
+                    chunksize=1,
                )
-                first = True
-                for r, output in results_it:
-                    if output:
-                        if first:
-                            first = False
-                        elif opt.project_header:
-                            print()
-                        # To simplify the DoWorkWrapper, take care of automatic
-                        # newlines.
-                        end = "\n"
-                        if output[-1] == "\n":
-                            end = ""
-                        print(output, end=end)
-                    rc = rc or r
-                    if r != 0 and opt.abort_on_errors:
-                        raise Exception("Aborting due to previous error")
        except (KeyboardInterrupt, WorkerKeyboardInterrupt):
            # Catch KeyboardInterrupt raised inside and outside of workers
-            rc = rc or errno.EINTR
+            rc = errno.EINTR
        except Exception as e:
            # Catch any other exceptions raised
            logger.error(
@ -300,35 +306,35 @@ without iterating through the remaining projects.
                type(e).__name__,
                e,
            )
-            rc = rc or getattr(e, "errno", 1)
+            rc = getattr(e, "errno", 1)
        if rc != 0:
            sys.exit(rc)

+    @classmethod
+    def InitWorker(cls):
+        signal.signal(signal.SIGINT, signal.SIG_IGN)
+
+    @classmethod
+    def DoWorkWrapper(cls, mirror, opt, cmd, shell, config, project_idx):
+        """A wrapper around the DoWork() method.
+
+        Catch the KeyboardInterrupt exceptions here and re-raise them as a
+        different, ``Exception``-based exception to stop it flooding the console
+        with stacktraces and making the parent hang indefinitely.
+
+        """
+        project = cls.get_parallel_context()["projects"][project_idx]
+        try:
+            return DoWork(project, mirror, opt, cmd, shell, project_idx, config)
+        except KeyboardInterrupt:
+            print("%s: Worker interrupted" % project.name)
+            raise WorkerKeyboardInterrupt()
+

 class WorkerKeyboardInterrupt(Exception):
    """Keyboard interrupt exception for worker processes."""


-def InitWorker():
-    signal.signal(signal.SIGINT, signal.SIG_IGN)
-
-
-def DoWorkWrapper(mirror, opt, cmd, shell, config, args):
-    """A wrapper around the DoWork() method.
-
-    Catch the KeyboardInterrupt exceptions here and re-raise them as a
-    different, ``Exception``-based exception to stop it flooding the console
-    with stacktraces and making the parent hang indefinitely.
-
-    """
-    cnt, project = args
-    try:
-        return DoWork(project, mirror, opt, cmd, shell, cnt, config)
-    except KeyboardInterrupt:
-        print("%s: Worker interrupted" % project.name)
-        raise WorkerKeyboardInterrupt()
-
-
 def DoWork(project, mirror, opt, cmd, shell, cnt, config):
    env = os.environ.copy()

--- a/subcmds/grep.py
+++ b/subcmds/grep.py
@ -23,7 +23,6 @@ from error import GitError
 from error import InvalidArgumentsError
 from error import SilentRepoExitError
 from git_command import GitCommand
-from project import Project
 from repo_logging import RepoLogger


@ -40,7 +39,7 @@ class GrepColoring(Coloring):
 class ExecuteOneResult(NamedTuple):
    """Result from an execute instance."""

-    project: Project
+    project_idx: int
    rc: int
    stdout: str
    stderr: str
@ -262,8 +261,10 @@ contain a line that matches both expressions:
            help="Show only file names not containing matching lines",
        )

-    def _ExecuteOne(self, cmd_argv, project):
+    @classmethod
+    def _ExecuteOne(cls, cmd_argv, project_idx):
        """Process one project."""
+        project = cls.get_parallel_context()["projects"][project_idx]
        try:
            p = GitCommand(
                project,
@ -274,7 +275,7 @@ contain a line that matches both expressions:
                verify_command=True,
            )
        except GitError as e:
-            return ExecuteOneResult(project, -1, None, str(e), e)
+            return ExecuteOneResult(project_idx, -1, None, str(e), e)

        try:
            error = None
@ -282,10 +283,12 @@ contain a line that matches both expressions:
        except GitError as e:
            rc = 1
            error = e
-        return ExecuteOneResult(project, rc, p.stdout, p.stderr, error)
+        return ExecuteOneResult(project_idx, rc, p.stdout, p.stderr, error)

    @staticmethod
-    def _ProcessResults(full_name, have_rev, opt, _pool, out, results):
+    def _ProcessResults(
+        full_name, have_rev, opt, projects, _pool, out, results
+    ):
        git_failed = False
        bad_rev = False
        have_match = False
@ -293,9 +296,10 @@ contain a line that matches both expressions:
        errors = []

        for result in results:
+            project = projects[result.project_idx]
            if result.rc < 0:
                git_failed = True
-                out.project("--- project %s ---" % _RelPath(result.project))
+                out.project("--- project %s ---" % _RelPath(project))
                out.nl()
                out.fail("%s", result.stderr)
                out.nl()
@ -311,9 +315,7 @@ contain a line that matches both expressions:
                    ):
                        bad_rev = True
                    else:
-                        out.project(
-                            "--- project %s ---" % _RelPath(result.project)
-                        )
+                        out.project("--- project %s ---" % _RelPath(project))
                        out.nl()
                        out.fail("%s", result.stderr.strip())
                        out.nl()
@ -331,13 +333,13 @@ contain a line that matches both expressions:
                    rev, line = line.split(":", 1)
                    out.write("%s", rev)
                    out.write(":")
-                    out.project(_RelPath(result.project))
+                    out.project(_RelPath(project))
                    out.write("/")
                    out.write("%s", line)
                    out.nl()
            elif full_name:
                for line in r:
-                    out.project(_RelPath(result.project))
+                    out.project(_RelPath(project))
                    out.write("/")
                    out.write("%s", line)
                    out.nl()
@ -381,16 +383,19 @@ contain a line that matches both expressions:
            cmd_argv.extend(opt.revision)
        cmd_argv.append("--")

-        git_failed, bad_rev, have_match, errors = self.ExecuteInParallel(
-            opt.jobs,
-            functools.partial(self._ExecuteOne, cmd_argv),
-            projects,
-            callback=functools.partial(
-                self._ProcessResults, full_name, have_rev, opt
-            ),
-            output=out,
-            ordered=True,
-        )
+        with self.ParallelContext():
+            self.get_parallel_context()["projects"] = projects
+            git_failed, bad_rev, have_match, errors = self.ExecuteInParallel(
+                opt.jobs,
+                functools.partial(self._ExecuteOne, cmd_argv),
+                range(len(projects)),
+                callback=functools.partial(
+                    self._ProcessResults, full_name, have_rev, opt, projects
+                ),
+                output=out,
+                ordered=True,
+                chunksize=1,
+            )

        if git_failed:
            raise GrepCommandError(
--- a/subcmds/init.py
+++ b/subcmds/init.py
@ -21,10 +21,9 @@ from command import MirrorSafeCommand
 from error import RepoUnhandledExceptionError
 from error import UpdateManifestError
 from git_command import git_require
-from git_command import MIN_GIT_VERSION_HARD
-from git_command import MIN_GIT_VERSION_SOFT
 from repo_logging import RepoLogger
 from wrapper import Wrapper
+from wrapper import WrapperDir


 logger = RepoLogger(__file__)
@ -53,6 +52,10 @@ The optional -b argument can be used to select the manifest branch
 to checkout and use.  If no branch is specified, the remote's default
 branch is used.  This is equivalent to using -b HEAD.

+The optional --manifest-upstream-branch argument can be used when a commit is
+provided to --manifest-branch (or -b), to specify the name of the git ref in
+which the commit can be found.
+
 The optional -m argument can be used to specify an alternate manifest
 to be used. If no manifest is specified, the manifest default.xml
 will be used.
@ -136,6 +139,7 @@ to update the working directory files.
        # manifest project is special and is created when instantiating the
        # manifest which happens before we parse options.
        self.manifest.manifestProject.clone_depth = opt.manifest_depth
+        self.manifest.manifestProject.upstream = opt.manifest_upstream_branch
        clone_filter_for_depth = (
            "blob:none" if (_REPO_ALLOW_SHALLOW == "0") else None
        )
@ -318,6 +322,12 @@ to update the working directory files.
                " be used with --standalone-manifest."
            )

+        if opt.manifest_upstream_branch and opt.manifest_branch is None:
+            self.OptionParser.error(
+                "--manifest-upstream-branch cannot be used without "
+                "--manifest-branch."
+            )
+
        if args:
            if opt.manifest_url:
                self.OptionParser.error(
@ -331,13 +341,17 @@ to update the working directory files.
                self.OptionParser.error("too many arguments to init")

    def Execute(self, opt, args):
-        git_require(MIN_GIT_VERSION_HARD, fail=True)
-        if not git_require(MIN_GIT_VERSION_SOFT):
+        wrapper = Wrapper()
+
+        reqs = wrapper.Requirements.from_dir(WrapperDir())
+        git_require(reqs.get_hard_ver("git"), fail=True)
+        min_git_version_soft = reqs.get_soft_ver("git")
+        if not git_require(min_git_version_soft):
            logger.warning(
                "repo: warning: git-%s+ will soon be required; "
                "please upgrade your version of git to maintain "
                "support.",
-                ".".join(str(x) for x in MIN_GIT_VERSION_SOFT),
+                ".".join(str(x) for x in min_git_version_soft),
            )

        rp = self.manifest.repoProject
@ -350,7 +364,6 @@ to update the working directory files.

        # Handle new --repo-rev requests.
        if opt.repo_rev:
-            wrapper = Wrapper()
            try:
                remote_ref, rev = wrapper.check_repo_rev(
                    rp.worktree,
--- a/subcmds/prune.py
+++ b/subcmds/prune.py
@ -27,8 +27,10 @@ class Prune(PagedCommand):
 """
    PARALLEL_JOBS = DEFAULT_LOCAL_JOBS

-    def _ExecuteOne(self, project):
+    @classmethod
+    def _ExecuteOne(cls, project_idx):
        """Process one project."""
+        project = cls.get_parallel_context()["projects"][project_idx]
        return project.PruneHeads()

    def Execute(self, opt, args):
@ -41,13 +43,15 @@ class Prune(PagedCommand):
        def _ProcessResults(_pool, _output, results):
            return list(itertools.chain.from_iterable(results))

-        all_branches = self.ExecuteInParallel(
-            opt.jobs,
-            self._ExecuteOne,
-            projects,
-            callback=_ProcessResults,
-            ordered=True,
-        )
+        with self.ParallelContext():
+            self.get_parallel_context()["projects"] = projects
+            all_branches = self.ExecuteInParallel(
+                opt.jobs,
+                self._ExecuteOne,
+                range(len(projects)),
+                callback=_ProcessResults,
+                ordered=True,
+            )

        if not all_branches:
            return
--- a/subcmds/start.py
+++ b/subcmds/start.py
@ -21,7 +21,6 @@ from error import RepoExitError
 from git_command import git
 from git_config import IsImmutable
 from progress import Progress
-from project import Project
 from repo_logging import RepoLogger


@ -29,7 +28,7 @@ logger = RepoLogger(__file__)


 class ExecuteOneResult(NamedTuple):
-    project: Project
+    project_idx: int
    error: Exception


@ -80,18 +79,20 @@ revision specified in the manifest.
        if not git.check_ref_format("heads/%s" % nb):
            self.OptionParser.error("'%s' is not a valid name" % nb)

-    def _ExecuteOne(self, revision, nb, project):
+    @classmethod
+    def _ExecuteOne(cls, revision, nb, default_revisionExpr, project_idx):
        """Start one project."""
        # If the current revision is immutable, such as a SHA1, a tag or
        # a change, then we can't push back to it. Substitute with
        # dest_branch, if defined; or with manifest default revision instead.
        branch_merge = ""
        error = None
+        project = cls.get_parallel_context()["projects"][project_idx]
        if IsImmutable(project.revisionExpr):
            if project.dest_branch:
                branch_merge = project.dest_branch
            else:
-                branch_merge = self.manifest.default.revisionExpr
+                branch_merge = default_revisionExpr

        try:
            project.StartBranch(
@ -100,7 +101,7 @@ revision specified in the manifest.
        except Exception as e:
            logger.error("error: unable to checkout %s: %s", project.name, e)
            error = e
-        return ExecuteOneResult(project, error)
+        return ExecuteOneResult(project_idx, error)

    def Execute(self, opt, args):
        nb = args[0]
@ -120,19 +121,28 @@ revision specified in the manifest.
        def _ProcessResults(_pool, pm, results):
            for result in results:
                if result.error:
-                    err_projects.append(result.project)
+                    project = all_projects[result.project_idx]
+                    err_projects.append(project)
                    err.append(result.error)
                pm.update(msg="")

-        self.ExecuteInParallel(
-            opt.jobs,
-            functools.partial(self._ExecuteOne, opt.revision, nb),
-            all_projects,
-            callback=_ProcessResults,
-            output=Progress(
-                f"Starting {nb}", len(all_projects), quiet=opt.quiet
-            ),
-        )
+        with self.ParallelContext():
+            self.get_parallel_context()["projects"] = all_projects
+            self.ExecuteInParallel(
+                opt.jobs,
+                functools.partial(
+                    self._ExecuteOne,
+                    opt.revision,
+                    nb,
+                    self.manifest.default.revisionExpr,
+                ),
+                range(len(all_projects)),
+                callback=_ProcessResults,
+                output=Progress(
+                    f"Starting {nb}", len(all_projects), quiet=opt.quiet
+                ),
+                chunksize=1,
+            )

        if err_projects:
            for p in err_projects:
--- a/subcmds/status.py
+++ b/subcmds/status.py
@ -88,7 +88,8 @@ the following meanings:
            "projects",
        )

-    def _StatusHelper(self, quiet, local, project):
+    @classmethod
+    def _StatusHelper(cls, quiet, local, project_idx):
        """Obtains the status for a specific project.

        Obtains the status for a project, redirecting the output to
@ -99,12 +100,13 @@ the following meanings:
            local: a boolean, if True, the path is relative to the local
                (sub)manifest.  If false, the path is relative to the outermost
                manifest.
-            project: Project to get status of.
+            project_idx: Project index to get status of.

        Returns:
            The status of the project.
        """
        buf = io.StringIO()
+        project = cls.get_parallel_context()["projects"][project_idx]
        ret = project.PrintWorkTreeStatus(
            quiet=quiet, output_redir=buf, local=local
        )
@ -143,15 +145,18 @@ the following meanings:
                    ret += 1
            return ret

-        counter = self.ExecuteInParallel(
-            opt.jobs,
-            functools.partial(
-                self._StatusHelper, opt.quiet, opt.this_manifest_only
-            ),
-            all_projects,
-            callback=_ProcessResults,
-            ordered=True,
-        )
+        with self.ParallelContext():
+            self.get_parallel_context()["projects"] = all_projects
+            counter = self.ExecuteInParallel(
+                opt.jobs,
+                functools.partial(
+                    self._StatusHelper, opt.quiet, opt.this_manifest_only
+                ),
+                range(len(all_projects)),
+                callback=_ProcessResults,
+                ordered=True,
+                chunksize=1,
+            )

        if not opt.quiet and len(all_projects) == counter:
            print("nothing to commit (working directory clean)")
--- a/subcmds/sync.py
+++ b/subcmds/sync.py
@ -131,12 +131,17 @@ def _SafeCheckoutOrder(checkouts: List[Project]) -> List[List[Project]]:
    return res


+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)
+
+
 class _FetchOneResult(NamedTuple):
    """_FetchOne return value.

    Attributes:
      success (bool): True if successful.
-      project (Project): The fetched project.
+      project_idx (int): The fetched project index.
      start (float): The starting time.time().
      finish (float): The ending time.time().
      remote_fetched (bool): True if the remote was actually queried.
@ -144,7 +149,7 @@ class _FetchOneResult(NamedTuple):

    success: bool
    errors: List[Exception]
-    project: Project
+    project_idx: int
    start: float
    finish: float
    remote_fetched: bool
@ -177,14 +182,14 @@ class _CheckoutOneResult(NamedTuple):

    Attributes:
      success (bool): True if successful.
-      project (Project): The project.
+      project_idx (int): The project index.
      start (float): The starting time.time().
      finish (float): The ending time.time().
    """

    success: bool
    errors: List[Exception]
-    project: Project
+    project_idx: int
    start: float
    finish: float

@ -400,6 +405,13 @@ later is required to fix a server side protocol bug.
            "projects no longer exist in the manifest. "
            "WARNING: this may cause loss of data",
        )
+        p.add_option(
+            "--rebase",
+            dest="rebase",
+            action="store_true",
+            help="rebase local commits regardless of whether they are "
+            "published",
+        )
        p.add_option(
            "-l",
            "--local-only",
@ -580,7 +592,8 @@ later is required to fix a server side protocol bug.
            branch = branch[len(R_HEADS) :]
        return branch

-    def _GetCurrentBranchOnly(self, opt, manifest):
+    @classmethod
+    def _GetCurrentBranchOnly(cls, opt, manifest):
        """Returns whether current-branch or use-superproject options are
        enabled.

@ -698,7 +711,8 @@ later is required to fix a server side protocol bug.
        if need_unload:
            m.outer_client.manifest.Unload()

-    def _FetchProjectList(self, opt, projects):
+    @classmethod
+    def _FetchProjectList(cls, opt, projects):
        """Main function of the fetch worker.

        The projects we're given share the same underlying git object store, so
@ -710,21 +724,23 @@ later is required to fix a server side protocol bug.
            opt: Program options returned from optparse.  See _Options().
            projects: Projects to fetch.
        """
-        return [self._FetchOne(opt, x) for x in projects]
+        return [cls._FetchOne(opt, x) for x in projects]

-    def _FetchOne(self, opt, project):
+    @classmethod
+    def _FetchOne(cls, opt, project_idx):
        """Fetch git objects for a single project.

        Args:
            opt: Program options returned from optparse.  See _Options().
-            project: Project object for the project to fetch.
+            project_idx: Project index for the project to fetch.

        Returns:
            Whether the fetch was successful.
        """
+        project = cls.get_parallel_context()["projects"][project_idx]
        start = time.time()
        k = f"{project.name} @ {project.relpath}"
-        self._sync_dict[k] = start
+        cls.get_parallel_context()["sync_dict"][k] = start
        success = False
        remote_fetched = False
        errors = []
@ -734,7 +750,7 @@ later is required to fix a server side protocol bug.
                quiet=opt.quiet,
                verbose=opt.verbose,
                output_redir=buf,
-                current_branch_only=self._GetCurrentBranchOnly(
+                current_branch_only=cls._GetCurrentBranchOnly(
                    opt, project.manifest
                ),
                force_sync=opt.force_sync,
@ -744,7 +760,7 @@ later is required to fix a server side protocol bug.
                optimized_fetch=opt.optimized_fetch,
                retry_fetches=opt.retry_fetches,
                prune=opt.prune,
-                ssh_proxy=self.ssh_proxy,
+                ssh_proxy=cls.get_parallel_context()["ssh_proxy"],
                clone_filter=project.manifest.CloneFilter,
                partial_clone_exclude=project.manifest.PartialCloneExclude,
                clone_filter_for_depth=project.manifest.CloneFilterForDepth,
@ -776,24 +792,20 @@ later is required to fix a server side protocol bug.
                type(e).__name__,
                e,
            )
-            del self._sync_dict[k]
            errors.append(e)
            raise
+        finally:
+            del cls.get_parallel_context()["sync_dict"][k]

        finish = time.time()
-        del self._sync_dict[k]
        return _FetchOneResult(
-            success, errors, project, start, finish, remote_fetched
+            success, errors, project_idx, start, finish, remote_fetched
        )

-    @classmethod
-    def _FetchInitChild(cls, ssh_proxy):
-        cls.ssh_proxy = ssh_proxy
-
    def _GetSyncProgressMessage(self):
        earliest_time = float("inf")
        earliest_proj = None
-        items = self._sync_dict.items()
+        items = self.get_parallel_context()["sync_dict"].items()
        for project, t in items:
            if t < earliest_time:
                earliest_time = t
@ -801,7 +813,7 @@ later is required to fix a server side protocol bug.

        if not earliest_proj:
            # This function is called when sync is still running but in some
-            # cases (by chance), _sync_dict can contain no entries. Return some
+            # cases (by chance), sync_dict can contain no entries. Return some
            # text to indicate that sync is still working.
            return "..working.."

@ -809,10 +821,19 @@ later is required to fix a server side protocol bug.
        jobs = jobs_str(len(items))
        return f"{jobs} | {elapsed_str(elapsed)} {earliest_proj}"

+    @classmethod
+    def InitWorker(cls):
+        # Force connect to the manager server now.
+        # This is good because workers are initialized one by one. Without this,
+        # multiple workers may connect to the manager when handling the first
+        # job at the same time. Then the connection may fail if too many
+        # connections are pending and execeeded the socket listening backlog,
+        # especially on MacOS.
+        len(cls.get_parallel_context()["sync_dict"])
+
    def _Fetch(self, projects, opt, err_event, ssh_proxy, errors):
        ret = True

-        jobs = opt.jobs_network
        fetched = set()
        remote_fetched = set()
        pm = Progress(
@ -824,7 +845,6 @@ later is required to fix a server side protocol bug.
            elide=True,
        )

-        self._sync_dict = multiprocessing.Manager().dict()
        sync_event = _threading.Event()

        def _MonitorSyncLoop():
@ -835,19 +855,13 @@ later is required to fix a server side protocol bug.

        sync_progress_thread = _threading.Thread(target=_MonitorSyncLoop)
        sync_progress_thread.daemon = True
-        sync_progress_thread.start()

-        objdir_project_map = dict()
-        for project in projects:
-            objdir_project_map.setdefault(project.objdir, []).append(project)
-        projects_list = list(objdir_project_map.values())
-
-        def _ProcessResults(results_sets):
+        def _ProcessResults(pool, pm, results_sets):
            ret = True
            for results in results_sets:
                for result in results:
                    success = result.success
-                    project = result.project
+                    project = projects[result.project_idx]
                    start = result.start
                    finish = result.finish
                    self._fetch_times.Set(project, finish - start)
@ -871,58 +885,50 @@ later is required to fix a server side protocol bug.
                        fetched.add(project.gitdir)
                    pm.update()
                if not ret and opt.fail_fast:
+                    if pool:
+                        pool.close()
                    break
            return ret

-        # We pass the ssh proxy settings via the class.  This allows
-        # multiprocessing to pickle it up when spawning children.  We can't pass
-        # it as an argument to _FetchProjectList below as multiprocessing is
-        # unable to pickle those.
-        Sync.ssh_proxy = None
+        with self.ParallelContext():
+            self.get_parallel_context()["projects"] = projects
+            self.get_parallel_context()[
+                "sync_dict"
+            ] = multiprocessing.Manager().dict()

-        # NB: Multiprocessing is heavy, so don't spin it up for one job.
-        if len(projects_list) == 1 or jobs == 1:
-            self._FetchInitChild(ssh_proxy)
-            if not _ProcessResults(
-                self._FetchProjectList(opt, x) for x in projects_list
-            ):
-                ret = False
-        else:
-            # Favor throughput over responsiveness when quiet.  It seems that
-            # imap() will yield results in batches relative to chunksize, so
-            # even as the children finish a sync, we won't see the result until
-            # one child finishes ~chunksize jobs.  When using a large --jobs
-            # with large chunksize, this can be jarring as there will be a large
-            # initial delay where repo looks like it isn't doing anything and
-            # sits at 0%, but then suddenly completes a lot of jobs all at once.
-            # Since this code is more network bound, we can accept a bit more
-            # CPU overhead with a smaller chunksize so that the user sees more
-            # immediate & continuous feedback.
-            if opt.quiet:
-                chunksize = WORKER_BATCH_SIZE
-            else:
+            objdir_project_map = dict()
+            for index, project in enumerate(projects):
+                objdir_project_map.setdefault(project.objdir, []).append(index)
+            projects_list = list(objdir_project_map.values())
+
+            jobs = min(opt.jobs_network, len(projects_list))
+
+            # We pass the ssh proxy settings via the class.  This allows
+            # multiprocessing to pickle it up when spawning children.  We can't
+            # pass it as an argument to _FetchProjectList below as
+            # multiprocessing is unable to pickle those.
+            self.get_parallel_context()["ssh_proxy"] = ssh_proxy
+
+            sync_progress_thread.start()
+            if not opt.quiet:
                pm.update(inc=0, msg="warming up")
-                chunksize = 4
-            with multiprocessing.Pool(
-                jobs, initializer=self._FetchInitChild, initargs=(ssh_proxy,)
-            ) as pool:
-                results = pool.imap_unordered(
+            try:
+                ret = self.ExecuteInParallel(
+                    jobs,
                    functools.partial(self._FetchProjectList, opt),
                    projects_list,
-                    chunksize=chunksize,
+                    callback=_ProcessResults,
+                    output=pm,
+                    # Use chunksize=1 to avoid the chance that some workers are
+                    # idle while other workers still have more than one job in
+                    # their chunk queue.
+                    chunksize=1,
+                    initializer=self.InitWorker,
                )
-                if not _ProcessResults(results):
-                    ret = False
-                    pool.close()
+            finally:
+                sync_event.set()
+                sync_progress_thread.join()

-        # Cleanup the reference now that we're done with it, and we're going to
-        # release any resources it points to.  If we don't, later
-        # multiprocessing usage (e.g. checkouts) will try to pickle and then
-        # crash.
-        del Sync.ssh_proxy
-
-        sync_event.set()
-        pm.end()
        self._fetch_times.Save()
        self._local_sync_state.Save()

@ -963,7 +969,9 @@ later is required to fix a server side protocol bug.
        if not success:
            err_event.set()

-        _PostRepoFetch(rp, opt.repo_verify)
+        # Call self update, unless requested not to
+        if os.environ.get("REPO_SKIP_SELF_UPDATE", "0") == "0":
+            _PostRepoFetch(rp, opt.repo_verify)
        if opt.network_only:
            # Bail out now; the rest touches the working tree.
            if err_event.is_set():
@ -1008,8 +1016,15 @@ later is required to fix a server side protocol bug.

        return _FetchMainResult(all_projects)

+    @classmethod
    def _CheckoutOne(
-        self, detach_head, force_sync, force_checkout, verbose, project
+        cls,
+        detach_head,
+        force_sync,
+        force_checkout,
+        force_rebase,
+        verbose,
+        project_idx,
    ):
        """Checkout work tree for one project

@ -1019,12 +1034,14 @@ later is required to fix a server side protocol bug.
            existing git directory that was previously linked to a different
            object directory).
            force_checkout: Force checking out of the repo content.
+            force_rebase: Force rebase.
            verbose: Whether to show verbose messages.
-            project: Project object for the project to checkout.
+            project_idx: Project index for the project to checkout.

        Returns:
            Whether the fetch was successful.
        """
+        project = cls.get_parallel_context()["projects"][project_idx]
        start = time.time()
        syncbuf = SyncBuffer(
            project.manifest.manifestProject.config, detach_head=detach_head
@ -1036,6 +1053,7 @@ later is required to fix a server side protocol bug.
                syncbuf,
                force_sync=force_sync,
                force_checkout=force_checkout,
+                force_rebase=force_rebase,
                errors=errors,
                verbose=verbose,
            )
@ -1057,7 +1075,7 @@ later is required to fix a server side protocol bug.
        if not success:
            logger.error("error: Cannot checkout %s", project.name)
        finish = time.time()
-        return _CheckoutOneResult(success, errors, project, start, finish)
+        return _CheckoutOneResult(success, errors, project_idx, start, finish)

    def _Checkout(self, all_projects, opt, err_results, checkout_errors):
        """Checkout projects listed in all_projects
@ -1075,7 +1093,9 @@ later is required to fix a server side protocol bug.
            ret = True
            for result in results:
                success = result.success
-                project = result.project
+                project = self.get_parallel_context()["projects"][
+                    result.project_idx
+                ]
                start = result.start
                finish = result.finish
                self.event_log.AddSync(
@ -1102,21 +1122,28 @@ later is required to fix a server side protocol bug.
            return ret

        for projects in _SafeCheckoutOrder(all_projects):
-            proc_res = self.ExecuteInParallel(
-                opt.jobs_checkout,
-                functools.partial(
-                    self._CheckoutOne,
-                    opt.detach_head,
-                    opt.force_sync,
-                    opt.force_checkout,
-                    opt.verbose,
-                ),
-                projects,
-                callback=_ProcessResults,
-                output=Progress(
-                    "Checking out", len(all_projects), quiet=opt.quiet
-                ),
-            )
+            with self.ParallelContext():
+                self.get_parallel_context()["projects"] = projects
+                proc_res = self.ExecuteInParallel(
+                    opt.jobs_checkout,
+                    functools.partial(
+                        self._CheckoutOne,
+                        opt.detach_head,
+                        opt.force_sync,
+                        opt.force_checkout,
+                        opt.rebase,
+                        opt.verbose,
+                    ),
+                    range(len(projects)),
+                    callback=_ProcessResults,
+                    output=Progress(
+                        "Checking out", len(all_projects), quiet=opt.quiet
+                    ),
+                    # Use chunksize=1 to avoid the chance that some workers are
+                    # idle while other workers still have more than one job in
+                    # their chunk queue.
+                    chunksize=1,
+                )

        self._local_sync_state.Save()
        return proc_res and not err_results
@ -1480,6 +1507,19 @@ later is required to fix a server side protocol bug.
                    [success, manifest_str] = server.GetApprovedManifest(
                        branch, target
                    )
+                elif (
+                    "TARGET_PRODUCT" in os.environ
+                    and "TARGET_BUILD_VARIANT" in os.environ
+                    and "TARGET_RELEASE" in os.environ
+                ):
+                    target = "%s-%s-%s" % (
+                        os.environ["TARGET_PRODUCT"],
+                        os.environ["TARGET_RELEASE"],
+                        os.environ["TARGET_BUILD_VARIANT"],
+                    )
+                    [success, manifest_str] = server.GetApprovedManifest(
+                        branch, target
+                    )
                elif (
                    "TARGET_PRODUCT" in os.environ
                    and "TARGET_BUILD_VARIANT" in os.environ
--- a/subcmds/upload.py
+++ b/subcmds/upload.py
@ -218,9 +218,14 @@ Gerrit Code Review:  https://www.gerritcodereview.com/
    def _Options(self, p):
        p.add_option(
            "-t",
+            "--topic-branch",
            dest="auto_topic",
            action="store_true",
-            help="send local branch name to Gerrit Code Review",
+            help="set the topic to the local branch name",
+        )
+        p.add_option(
+            "--topic",
+            help="set topic for the change",
        )
        p.add_option(
            "--hashtag",
@ -549,42 +554,14 @@ Gerrit Code Review:  https://www.gerritcodereview.com/
        people = copy.deepcopy(original_people)
        self._AppendAutoList(branch, people)

-        # Check if there are local changes that may have been forgotten.
-        changes = branch.project.UncommitedFiles()
-        if opt.ignore_untracked_files:
-            untracked = set(branch.project.UntrackedFiles())
-            changes = [x for x in changes if x not in untracked]
-
-        if changes:
-            key = "review.%s.autoupload" % branch.project.remote.review
-            answer = branch.project.config.GetBoolean(key)
-
-            # If they want to auto upload, let's not ask because it
-            # could be automated.
-            if answer is None:
-                print()
-                print(
-                    "Uncommitted changes in %s (did you forget to "
-                    "amend?):" % branch.project.name
-                )
-                print("\n".join(changes))
-                print("Continue uploading? (y/N) ", end="", flush=True)
-                if opt.yes:
-                    print("<--yes>")
-                    a = "yes"
-                else:
-                    a = sys.stdin.readline().strip().lower()
-                if a not in ("y", "yes", "t", "true", "on"):
-                    print("skipping upload", file=sys.stderr)
-                    branch.uploaded = False
-                    branch.error = "User aborted"
-                    return
-
        # Check if topic branches should be sent to the server during
        # upload.
-        if opt.auto_topic is not True:
-            key = "review.%s.uploadtopic" % branch.project.remote.review
-            opt.auto_topic = branch.project.config.GetBoolean(key)
+        if opt.topic is None:
+            if opt.auto_topic is not True:
+                key = "review.%s.uploadtopic" % branch.project.remote.review
+                opt.auto_topic = branch.project.config.GetBoolean(key)
+            if opt.auto_topic:
+                opt.topic = branch.name

        def _ExpandCommaList(value):
            """Split |value| up into comma delimited entries."""
@ -626,19 +603,22 @@ Gerrit Code Review:  https://www.gerritcodereview.com/
            full_dest = destination
            if not full_dest.startswith(R_HEADS):
                full_dest = R_HEADS + full_dest
+            full_revision = branch.project.revisionExpr
+            if not full_revision.startswith(R_HEADS):
+                full_revision = R_HEADS + full_revision

            # If the merge branch of the local branch is different from
            # the project's revision AND destination, this might not be
            # intentional.
            if (
                merge_branch
-                and merge_branch != branch.project.revisionExpr
+                and merge_branch != full_revision
                and merge_branch != full_dest
            ):
                print(
                    f"For local branch {branch.name}: merge branch "
                    f"{merge_branch} does not match destination branch "
-                    f"{destination}"
+                    f"{destination} and revision {branch.project.revisionExpr}"
                )
                print("skipping upload.")
                print(
@ -651,7 +631,7 @@ Gerrit Code Review:  https://www.gerritcodereview.com/
        branch.UploadForReview(
            people,
            dryrun=opt.dryrun,
-            auto_topic=opt.auto_topic,
+            topic=opt.topic,
            hashtags=hashtags,
            labels=labels,
            private=opt.private,
@ -736,16 +716,17 @@ Gerrit Code Review:  https://www.gerritcodereview.com/
        merge_branch = p.stdout.strip()
        return merge_branch

-    @staticmethod
-    def _GatherOne(opt, project):
+    @classmethod
+    def _GatherOne(cls, opt, project_idx):
        """Figure out the upload status for |project|."""
+        project = cls.get_parallel_context()["projects"][project_idx]
        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, avail)
+        return (project_idx, avail)

    def Execute(self, opt, args):
        projects = self.GetProjects(
@ -755,7 +736,8 @@ Gerrit Code Review:  https://www.gerritcodereview.com/
        def _ProcessResults(_pool, _out, results):
            pending = []
            for result in results:
-                project, avail = result
+                project_idx, avail = result
+                project = projects[project_idx]
                if avail is None:
                    logger.error(
                        'repo: error: %s: Unable to upload branch "%s". '
@ -766,15 +748,17 @@ Gerrit Code Review:  https://www.gerritcodereview.com/
                        project.manifest.branch,
                    )
                elif avail:
-                    pending.append(result)
+                    pending.append((project, avail))
            return pending

-        pending = self.ExecuteInParallel(
-            opt.jobs,
-            functools.partial(self._GatherOne, opt),
-            projects,
-            callback=_ProcessResults,
-        )
+        with self.ParallelContext():
+            self.get_parallel_context()["projects"] = projects
+            pending = self.ExecuteInParallel(
+                opt.jobs,
+                functools.partial(self._GatherOne, opt),
+                range(len(projects)),
+                callback=_ProcessResults,
+            )

        if not pending:
            if opt.branch is None:
--- a/tests/fixtures/test.gitconfig
+++ b/tests/fixtures/test.gitconfig
@ -11,3 +11,11 @@
 	intk = 10k
 	intm = 10m
 	intg = 10g
+
+[color "status"]
+	one = yellow
+	two = magenta cyan
+	three = black red ul
+	reset = reset
+	none
+	empty =
--- a/tests/test_color.py
+++ b/tests/test_color.py
@ -0,0 +1,74 @@
+# Copyright (C) 2024 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 color.py module."""
+
+import os
+import unittest
+
+import color
+import git_config
+
+
+def fixture(*paths):
+    """Return a path relative to test/fixtures."""
+    return os.path.join(os.path.dirname(__file__), "fixtures", *paths)
+
+
+class ColoringTests(unittest.TestCase):
+    """tests of the Coloring class."""
+
+    def setUp(self):
+        """Create a GitConfig object using the test.gitconfig fixture."""
+        config_fixture = fixture("test.gitconfig")
+        self.config = git_config.GitConfig(config_fixture)
+        color.SetDefaultColoring("true")
+        self.color = color.Coloring(self.config, "status")
+
+    def test_Color_Parse_all_params_none(self):
+        """all params are None"""
+        val = self.color._parse(None, None, None, None)
+        self.assertEqual("", val)
+
+    def test_Color_Parse_first_parameter_none(self):
+        """check fg & bg & attr"""
+        val = self.color._parse(None, "black", "red", "ul")
+        self.assertEqual("\x1b[4;30;41m", val)
+
+    def test_Color_Parse_one_entry(self):
+        """check fg"""
+        val = self.color._parse("one", None, None, None)
+        self.assertEqual("\033[33m", val)
+
+    def test_Color_Parse_two_entry(self):
+        """check fg & bg"""
+        val = self.color._parse("two", None, None, None)
+        self.assertEqual("\033[35;46m", val)
+
+    def test_Color_Parse_three_entry(self):
+        """check fg & bg & attr"""
+        val = self.color._parse("three", None, None, None)
+        self.assertEqual("\033[4;30;41m", val)
+
+    def test_Color_Parse_reset_entry(self):
+        """check reset entry"""
+        val = self.color._parse("reset", None, None, None)
+        self.assertEqual("\033[m", val)
+
+    def test_Color_Parse_empty_entry(self):
+        """check empty entry"""
+        val = self.color._parse("none", "blue", "white", "dim")
+        self.assertEqual("\033[2;34;47m", val)
+        val = self.color._parse("empty", "green", "white", "bold")
+        self.assertEqual("\033[1;32;47m", val)
--- a/tests/test_manifest_xml.py
+++ b/tests/test_manifest_xml.py
@ -1049,6 +1049,91 @@ class RemoveProjectElementTests(ManifestParseTestCase):
        self.assertTrue(found_proj1_path1)
        self.assertTrue(found_proj2)

+    def test_base_revision_checks_on_patching(self):
+        manifest_fail_wrong_tag = self.getXmlManifest(
+            """
+<manifest>
+  <remote name="default-remote" fetch="http://localhost" />
+  <default remote="default-remote" revision="tag.002" />
+  <project name="project1" path="tests/path1" />
+  <extend-project name="project1" revision="new_hash" base-rev="tag.001" />
+</manifest>
+"""
+        )
+        with self.assertRaises(error.ManifestParseError):
+            manifest_fail_wrong_tag.ToXml()
+
+        manifest_fail_remove = self.getXmlManifest(
+            """
+<manifest>
+  <remote name="default-remote" fetch="http://localhost" />
+  <default remote="default-remote" revision="refs/heads/main" />
+  <project name="project1" path="tests/path1" revision="hash1" />
+  <remove-project name="project1" base-rev="wrong_hash" />
+</manifest>
+"""
+        )
+        with self.assertRaises(error.ManifestParseError):
+            manifest_fail_remove.ToXml()
+
+        manifest_fail_extend = self.getXmlManifest(
+            """
+<manifest>
+  <remote name="default-remote" fetch="http://localhost" />
+  <default remote="default-remote" revision="refs/heads/main" />
+  <project name="project1" path="tests/path1" revision="hash1" />
+  <extend-project name="project1" revision="new_hash" base-rev="wrong_hash" />
+</manifest>
+"""
+        )
+        with self.assertRaises(error.ManifestParseError):
+            manifest_fail_extend.ToXml()
+
+        manifest_fail_unknown = self.getXmlManifest(
+            """
+<manifest>
+  <remote name="default-remote" fetch="http://localhost" />
+  <default remote="default-remote" revision="refs/heads/main" />
+  <project name="project1" path="tests/path1" />
+  <extend-project name="project1" revision="new_hash" base-rev="any_hash" />
+</manifest>
+"""
+        )
+        with self.assertRaises(error.ManifestParseError):
+            manifest_fail_unknown.ToXml()
+
+        manifest_ok = self.getXmlManifest(
+            """
+<manifest>
+  <remote name="default-remote" fetch="http://localhost" />
+  <default remote="default-remote" revision="refs/heads/main" />
+  <project name="project1" path="tests/path1" revision="hash1" />
+  <project name="project2" path="tests/path2" revision="hash2" />
+  <project name="project3" path="tests/path3" revision="hash3" />
+  <project name="project4" path="tests/path4" revision="hash4" />
+
+  <remove-project name="project1" />
+  <remove-project name="project2" base-rev="hash2" />
+  <project name="project2" path="tests/path2" revision="new_hash2" />
+  <extend-project name="project3" base-rev="hash3" revision="new_hash3" />
+  <extend-project name="project3" base-rev="new_hash3" revision="newer_hash3" />
+  <remove-project path="tests/path4" base-rev="hash4" />
+</manifest>
+"""
+        )
+        found_proj2 = False
+        found_proj3 = False
+        for proj in manifest_ok.projects:
+            if proj.name == "project2":
+                found_proj2 = True
+            if proj.name == "project3":
+                found_proj3 = True
+            self.assertNotEqual(proj.name, "project1")
+            self.assertNotEqual(proj.name, "project4")
+        self.assertTrue(found_proj2)
+        self.assertTrue(found_proj3)
+        self.assertTrue(len(manifest_ok.projects) == 2)
+

 class ExtendProjectElementTests(ManifestParseTestCase):
    """Tests for <extend-project>."""
--- a/tests/test_repo_logging.py
+++ b/tests/test_repo_logging.py
@ -13,9 +13,14 @@
 # limitations under the License.

 """Unit test for repo_logging module."""
+
+import contextlib
+import io
+import logging
 import unittest
 from unittest import mock

+from color import SetDefaultColoring
 from error import RepoExitError
 from repo_logging import RepoLogger

@ -62,3 +67,35 @@ class TestRepoLogger(unittest.TestCase):
                mock.call("Repo command failed: %s", "RepoExitError"),
            ]
        )
+
+    def test_log_with_format_string(self):
+        """Test different log levels with format strings."""
+
+        # Set color output to "always" for consistent test results.
+        # This ensures the logger's behavior is uniform across different
+        # environments and git configurations.
+        SetDefaultColoring("always")
+
+        # Regex pattern to match optional ANSI color codes.
+        # \033    - Escape character
+        # \[      - Opening square bracket
+        # [0-9;]* - Zero or more digits or semicolons
+        # m       - Ending 'm' character
+        # ?       - Makes the entire group optional
+        opt_color = r"(\033\[[0-9;]*m)?"
+
+        for level in (logging.INFO, logging.WARN, logging.ERROR):
+            name = logging.getLevelName(level)
+
+            with self.subTest(level=level, name=name):
+                output = io.StringIO()
+
+                with contextlib.redirect_stderr(output):
+                    logger = RepoLogger(__name__)
+                    logger.log(level, "%s", "100% pass")
+
+                self.assertRegex(
+                    output.getvalue().strip(),
+                    f"^{opt_color}100% pass{opt_color}$",
+                    f"failed for level {name}",
+                )
--- a/tests/test_subcmds_sync.py
+++ b/tests/test_subcmds_sync.py
@ -355,6 +355,30 @@ class SafeCheckoutOrder(unittest.TestCase):
        )


+class Chunksize(unittest.TestCase):
+    """Tests for _chunksize."""
+
+    def test_single_project(self):
+        """Single project."""
+        self.assertEqual(sync._chunksize(1, 1), 1)
+
+    def test_low_project_count(self):
+        """Multiple projects, low number of projects to sync."""
+        self.assertEqual(sync._chunksize(10, 1), 10)
+        self.assertEqual(sync._chunksize(10, 2), 5)
+        self.assertEqual(sync._chunksize(10, 4), 2)
+        self.assertEqual(sync._chunksize(10, 8), 1)
+        self.assertEqual(sync._chunksize(10, 16), 1)
+
+    def test_high_project_count(self):
+        """Multiple projects, high number of projects to sync."""
+        self.assertEqual(sync._chunksize(2800, 1), 32)
+        self.assertEqual(sync._chunksize(2800, 16), 32)
+        self.assertEqual(sync._chunksize(2800, 32), 32)
+        self.assertEqual(sync._chunksize(2800, 64), 32)
+        self.assertEqual(sync._chunksize(2800, 128), 21)
+
+
 class GetPreciousObjectsState(unittest.TestCase):
    """Tests for _GetPreciousObjectsState."""

--- a/tox.ini
+++ b/tox.ini
@ -30,6 +30,7 @@ python =

 [testenv]
 deps =
+    -c constraints.txt
    black
    flake8
    isort
@ -44,17 +45,19 @@ setenv =
 [testenv:lint]
 skip_install = true
 deps =
+    -c constraints.txt
    black
    flake8
 commands =
-    black --check {posargs:.}
+    black --check {posargs:. repo run_tests release/update-hooks release/update-manpages}
    flake8

 [testenv:format]
 skip_install = true
 deps =
+    -c constraints.txt
    black
    flake8
 commands =
-    black {posargs:.}
+    black {posargs:. repo run_tests release/update-hooks release/update-manpages}
    flake8
--- a/wrapper.py
+++ b/wrapper.py
@ -18,8 +18,12 @@ import importlib.util
 import os


+def WrapperDir():
+    return os.path.dirname(__file__)
+
+
 def WrapperPath():
-    return os.path.join(os.path.dirname(__file__), "repo")
+    return os.path.join(WrapperDir(), "repo")


@functools.lru_cache(maxsize=None)