After repo.fetchcmd exits, _CustomFetch verified the tracking ref and
FETCH_HEAD with ResolveCommit, i.e. `git rev-parse --verify
<ref>^{commit}`. Peeling to a commit makes Git look the object up: it
opens every pack index in objects/pack/ until it finds the commit, then
reads the commit from its packfile.
fetchcmd exists for object stores that are populated lazily, such as
ABFS, whose `abfs git fetch` registers packfiles as virtual files and
returns at once. There the peel is the first read of the packs the
command registered, and it blocks until they are downloaded. A project
whose revision did not change needs no objects to sync, yet paid that
download whenever fetchcmd registered new packs for it.
Compare the object IDs that the refs record instead (ResolveRef, which
runs the same rev-parse without the peel). Only when they differ peel
both sides to commits, so an annotated tag still matches the commit it
points to. A commit missing from the object store now fails the checkout
that reads it instead of the network half.
On a first sync the checkout reads the commit anyway, so there the
download only moves to the next command that needs the object.
Bug: 543101585
Change-Id: I51248ff1e9674b16e3ff8cee69572dbc8c7a8e99
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/643003
Commit-Queue: Gavin Mak <gavinmak@google.com>
Tested-by: Gavin Mak <gavinmak@google.com>
Reviewed-by: Brian Gan <brgan@google.com>
When a project's revision is an unpinned branch or tag and superprojects
are not used (so self.revisionId is unset), _CustomFetch previously ran
git ls-remote against the Git remote before invoking repo.fetchcmd just
to pre-populate REPO_TREV.
This added a per-project network round-trip before fetchcmd and forced
branch resolution against the Git remote rather than letting fetchcmd
resolve REPO_RREV from its own server (just as standard git fetch does
in _RemoteFetch).
Only populate REPO_TREV before fetchcmd when the target commit SHA is
already known (via self.revisionId from superproject or a SHA-pinned
revisionExpr). When REPO_RREV is an unpinned branch or tag, leave
REPO_TREV empty, let fetchcmd resolve REPO_RREV and update the local
tracking ref and FETCH_HEAD, and verify afterward that the tracking ref
and FETCH_HEAD resolve to the same valid commit in the object store.
Bug: 543101585
Change-Id: I482bf4c022d0e669e5620d4517581ac193983da0
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/640423
Reviewed-by: Brian Gan <brgan@google.com>
Commit-Queue: Gavin Mak <gavinmak@google.com>
Tested-by: Gavin Mak <gavinmak@google.com>
Add `repo.reprojectcmd`, the checkout counterpart to `repo.fetchcmd`.
When set, `repo sync` runs this command instead of Git to materialize a
project's index and worktree at the target tree, while `repo` handles
ref updates directly via `git update-ref`.
This replaces Git's tree materialization steps: detaching HEAD,
fast-forwarding, and hard-resetting. Rebasing is not delegated, and the
command is skipped if HEAD is already at the target, if HEAD is ahead of
the target during fast-forward, or for MetaProjects.
The command runs in a subshell with project environment variables (such
as `REPO_TREV`). Before running, `repo` ensures no operation is in
progress and no staged changes exist. Worktree collision detection is
delegated to the command (preserving benign unstaged/untracked edits).
Afterward, `repo` verifies that HEAD was untouched and that the index
matches the target tree.
Like `repo.fetchcmd`, this requires `repo.uselocalgitdirs`. Nested
projects and submodules are unsupported; `repo sync` fails if the
manifest contains any while `repo.reprojectcmd` is enabled.
Verified end-to-end with repo init using local-gitdirs, repo.fetchcmd,
and repo.reprojectcmd ('git -C $REPO_PATH read-tree -m -u $REPO_TREV'):
* Verified detached HEAD checkout and correct reflog generation across
projects.
* Verified benign unstaged edits and untracked files survive checkout.
* Verified conflicting untracked files fail with exit 128 without
clobbering worktree.
* Verified staged changes fail upfront before reprojectcmd is executed.
Bug: 513329573
Change-Id: I964d24d22dccffc05a9b991ad69f3a7e93268c01
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/626281
Tested-by: Gavin Mak <gavinmak@google.com>
Reviewed-by: Brian Gan <brgan@google.com>
Commit-Queue: Gavin Mak <gavinmak@google.com>
Introduce support for `repo.fetchcmd` configuration, allowing users to
specify a custom command to fetch project data instead of
`_RemoteFetch`.
When `repo.fetchcmd` is specified, `repo` will execute it instead of
`_RemoteFetch` during the network half of sync. Note that
`repo.fetchcmd` requires `repo.uselocalgitdirs` to be enabled.
The command is executed in a subshell with project-context environment
variables, including the new `REPO_TREV` (target revision resolved to a
commit hash) and `REPO_PROJECT_FETCH_URL`.
After execution, `repo` verifies that the target commit is available and
that the tracking ref and FETCH_HEAD are correctly updated.
Tested with:
```
> ~/git-repo/repo init -u https://android-review.googlesource.com/platform/manifest \
--repo-url file:///usr/local/google/home/gavinmak/git-repo \
--groups developers \
--no-repo-verify \
--use-local-gitdirs
...
> git config --file .repo/manifests.git/config repo.fetchcmd 'mkdir -p $REPO_PATH && cd $REPO_PATH && if [ ! -d .git ]; then git init && git remote add aosp $REPO_PROJECT_FETCH_URL; fi && git fetch aosp $REPO_TREV && git reset --hard $REPO_TREV && mkdir -p .git/refs/remotes/aosp && echo $REPO_TREV > .git/refs/remotes/aosp/main && echo $REPO_TREV > .git/FETCH_HEAD'
> ~/git-repo/repo sync -j32
warning: repo is not tracking a remote branch, so it will not receive updates; run `repo init --repo-rev=stable` to fix.
You are currently enrolled in Git submodules experiment (go/android-submodules-quickstart). Use --no-use-superproject to override.
Syncing: 100% (4/4), done in 1m15.686s
Finalizing sync state...
repo sync has finished successfully.
```
Bug: 513329573
Change-Id: I754d3f3c78e86fdeee1a72115297a75b571bc497
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/583883
Reviewed-by: Becky Siegel <beckysiegel@google.com>
Tested-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Gavin Mak <gavinmak@google.com>
Gavin Mak