Add a configuration variable to control the default behavior of git replay
for updating references. This allows users who prefer the traditional
pipeline output to set it once in their config instead of passing
--ref-action=print with every command.
The config variable uses string values that mirror the behavior modes:
* replay.refAction = update (default): atomic ref updates
* replay.refAction = print: output commands for pipeline
Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Elijah Newren <newren@gmail.com>
Helped-by: Christian Couder <christian.couder@gmail.com>
Helped-by: Phillip Wood <phillip.wood123@gmail.com>
Signed-off-by: Siddharth Asthana <siddharthasthana31@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The git replay command currently outputs update commands that can be
piped to update-ref to achieve a rebase, e.g.
git replay --onto main topic1..topic2 | git update-ref --stdin
This separation had advantages for three special cases:
* it made testing easy (when state isn't modified from one step to
the next, you don't need to make temporary branches or have undo
commands, or try to track the changes)
* it provided a natural can-it-rebase-cleanly (and what would it
rebase to) capability without automatically updating refs, similar
to a --dry-run
* it provided a natural low-level tool for the suite of hash-object,
mktree, commit-tree, mktag, merge-tree, and update-ref, allowing
users to have another building block for experimentation and making
new tools
However, it should be noted that all three of these are somewhat
special cases; users, whether on the client or server side, would
almost certainly find it more ergonomic to simply have the updating
of refs be the default.
For server-side operations in particular, the pipeline architecture
creates process coordination overhead. Server implementations that need
to perform rebases atomically must maintain additional code to:
1. Spawn and manage a pipeline between git-replay and git-update-ref
2. Coordinate stdout/stderr streams across the pipe boundary
3. Handle partial failure states if the pipeline breaks mid-execution
4. Parse and validate the update-ref command output
Change the default behavior to update refs directly, and atomically (at
least to the extent supported by the refs backend in use). This
eliminates the process coordination overhead for the common case.
For users needing the traditional pipeline workflow, add a new
--ref-action=<mode> option that preserves the original behavior:
git replay --ref-action=print --onto main topic1..topic2 | git update-ref --stdin
The mode can be:
* update (default): Update refs directly using an atomic transaction
* print: Output update-ref commands for pipeline use
Test suite changes:
All existing tests that expected command output now use
--ref-action=print to preserve their original behavior. This keeps
the tests valid while allowing them to verify that the pipeline workflow
still works correctly.
New tests were added to verify:
- Default atomic behavior (no output, refs updated directly)
- Bare repository support (server-side use case)
- Equivalence between traditional pipeline and atomic updates
- Real atomicity using a lock file to verify all-or-nothing guarantee
- Test isolation using test_when_finished to clean up state
- Reflog messages include replay mode and target
A following commit will add a replay.refAction configuration
option for users who prefer the traditional pipeline output as their
default behavior.
Helped-by: Elijah Newren <newren@gmail.com>
Helped-by: Patrick Steinhardt <ps@pks.im>
Helped-by: Christian Couder <christian.couder@gmail.com>
Helped-by: Phillip Wood <phillip.wood123@gmail.com>
Signed-off-by: Siddharth Asthana <siddharthasthana31@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are two issues here.
First, when merge.directoryRenames is set to false, there are a few code
paths that should be turned off. I missed one; collect_renames() was
still doing some directory rename detection logic unconditionally. It
ended up not having much effect because
get_provisional_directory_renames() was skipped earlier and not setting
up renames->dir_renames, but the code should still be skipped.
Second, the larger issue is that sometimes we get a cached_pair rename
from a previous commit being replayed mapping A->B, but in a subsequent
commit but collect_merge_info() doesn't even recurse into the
directory containing B because there are no source pairings for that
rename that are relevant; we can merge that commit fine without knowing
the rename. But since the cached renames are added to the normal
renames, when we go to process it and find that B is not part of
opt->priv->paths, we hit the assertion error
process_renames: Assertion `newinfo && ~newinfo->merged.clean` failed.
I think we could fix this at the beginning of detect_regular_renames() by
pruning from cached_pairs any entry whose destination isn't in
opt->priv->paths, but it's suboptimal in that we'd kind of like the
cached_pair to be restored afterwards so that it can help the subsequent
commit, but more importantly since it sits at the intersection of
the caching renames optimization and the relevant renames optimization,
and the trivial directory resolution optimization, and I don't currently
have Documentation/technical/remembering-renames.txt fully paged in, I'm
not sure if that's a full solution or a bandaid for the current
testcase. However, since the remembering renames optimization was the
weakest of the set, and the optimization is far less important when
directory rename detection is off (as that implies far fewer potential
renames), let's just use a bigger hammer to ensure this special case is
fixed: turn off the rename caching. We do the same thing already when
we encounter rename/rename(1to1) cases (as per `git grep -3
disabling.the.optimization`, though it uses a slightly different
triggering mechanism since it's trying to affect the next time that
merge_check_renames_reusable() is called), and I think it makes sense
to do the same here.
Signed-off-by: Elijah Newren <newren@gmail.com>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There is a bug in the way renames are cached that rears its head when
`merge.directoryRenames` is set to false; it results in the following
message:
merge-ort.c:3002: process_renames: Assertion `newinfo && !newinfo->merged.clean' failed.
Aborted
It is quite a curious bug: the same test case will succeed, without any
assertion, if instead run with `merge.directoryRenames=true`.
Further, the assertion does not manifest while replaying the first
commit, it manifests while replaying the _second_ commit of the commit
range. But it does _not_ manifest when the second commit is replayed
individually.
This would indicate that there is an incomplete rename cache left-over
from the first replayed commit which is being reused for the second
commit, and if directory rename detection is enabled, the missing paths
are somehow regenerated.
Incidentally, the same bug can by triggered by modifying t6429 to switch
from merge.directoryRenames=true to merge.directoryRenames=false.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
[en: tweaked the commit message slightly, including adjusting the
line number of the assertion to the latest version, and the much
later discovery that a simple t6429 tweak would also display the
issue.]
Signed-off-by: Elijah Newren <newren@gmail.com>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that the default value for TEST_PASSES_SANITIZE_LEAK is `true` there
is no longer a need to have that variable declared in all of our tests.
Drop it.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The `advance_name` variable can either contain a static string when
parsed via the `--advance` command line option or it may be an allocated
string when set via `determine_replay_mode()`. Because we cannot be sure
whether it is allocated or not we just didn't free it at all, resulting
in a memory leak.
Split up the variables such that we can track the static and allocated
strings separately and then free the allocated one to fix the memory
leak.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The replay command is able to replay multiple branches but when some of
them are based on other replayed branches, their commit should be
replayed onto already replayed commits.
For this purpose, let's store the replayed commit and its original
commit in a key value store, so that we can easily find and reuse a
replayed commit instead of the original one.
Co-authored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Let's add a `--contained` option that can be used along with
`--onto` to rebase all the branches contained in the <revision-range>
argument.
Co-authored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There is already a 'rebase' mode with `--onto`. Let's add an 'advance' or
'cherry-pick' mode with `--advance`. This new mode will make the target
branch advance as we replay commits onto it.
The replayed commits should have a single tip, so that it's clear where
the target branch should be advanced. If they have more than one tip,
this new mode will error out.
Co-authored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of the fixed "<oldbase> <branch>" arguments, the replay
command now accepts "<revision-range>..." arguments in a similar
way as many other Git commands. This makes its interface more
standard and more flexible.
This also enables many revision related options accepted and
eaten by setup_revisions(). If the replay command was a high level
one or had a high level mode, it would make sense to restrict some
of the possible options, like those generating non-contiguous
history, as they could be confusing for most users.
Also as the interface of the command is now mostly finalized,
we can add more documentation and more testcases to make sure
the command will continue to work as designed in the future.
We only document the rev-list related options among all the
revision related options that are now accepted, as the rev-list
related ones are probably the most useful for now.
Helped-by: Dragan Simic <dsimic@manjaro.org>
Helped-by: Linus Arver <linusa@google.com>
Co-authored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We want this command to be a minimal command that just does server side
picking of commits, displaying the results on stdout for higher level
scripts to consume.
So let's simplify it:
* remove the worktree and index reading/writing,
* remove the ref (and reflog) updating,
* remove the assumptions tying us to HEAD, since (a) this is not a
rebase and (b) we want to be able to pick commits in a bare repo,
i.e. to/from branches that are not checked out and not the main
branch,
* remove unneeded includes,
* handle rebasing multiple branches by printing on stdout the update
ref commands that should be performed.
The output can be piped into `git update-ref --stdin` for the ref
updates to happen.
In the future to make it easier for users to use this command
directly maybe an option can be added to automatically pipe its output
into `git update-ref`.
Co-authored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We want replay to be a command that can be used on the server side on
any branch, not just the current one, so we are going to stop updating
HEAD in a future commit.
A "sanity check" that makes sure we are replaying the current branch
doesn't make sense anymore. Let's remove it.
Co-authored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
For now, this is just a rename from `t/helper/test-fast-rebase.c` into
`builtin/replay.c` with minimal changes to make it build appropriately.
Let's add a stub documentation and a stub test script though.
Subsequent commits will flesh out the capabilities of the new command
and make it a more standard regular builtin.
Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Co-authored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
