An interactive rebase provides opportunities for the user to edit the
todo list. The --update-refs option initializes the list with some
'update-ref <ref>' steps, but the user could add these manually.
Further, the user could add or remove these steps during pauses in the
interactive rebase.
Add a new method, todo_list_filter_update_refs(), that scans a todo_list
and compares it to the stored update-refs file. There are two actions
that can happen at this point:
1. If a '<ref>/<before>/<after>' triple in the update-refs file does not
have a matching 'update-ref <ref>' command in the todo-list _and_ the
<after> value is the null OID, then remove that triple. Here, the
user removed the 'update-ref <ref>' command before it was executed,
since if it was executed then the <after> value would store the
commit at that position.
2. If a 'update-ref <ref>' command in the todo-list does not have a
matching '<ref>/<before>/<after>' triple in the update-refs file,
then insert a new one. Store the <before> value to be the current
OID pointed at by <ref>. This is handled inside of the
init_update_ref_record() helper method.
We can test that this works by rewriting the todo-list several times in
the course of a rebase. Check that each ref is locked or unlocked for
updates after each todo-list update. We can also verify that the ref
update fails if a concurrent process updates one of the refs after the
rebase process records the "locked" ref location.
To help these tests, add a new 'set_replace_editor' helper that will
replace the todo-list with an exact file.
Reported-by: Phillip Wood <phillip.wood123@gmail.com>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When working on a large feature, it can be helpful to break that feature
into multiple smaller parts that become reviewed in sequence. During
development or during review, a change to one part of the feature could
affect multiple of these parts. An interactive rebase can help adjust
the multi-part "story" of the branch.
However, if there are branches tracking the different parts of the
feature, then rebasing the entire list of commits can create commits not
reachable from those "sub branches". It can take a manual step to update
those branches.
Add a new --update-refs option to 'git rebase -i' that adds 'update-ref
<ref>' steps to the todo file whenever a commit that is being rebased is
decorated with that <ref>. At the very end, the rebase process updates
all of the listed refs to the values stored during the rebase operation.
Be sure to iterate after any squashing or fixups are placed. Update the
branch only after those squashes and fixups are complete. This allows a
--fixup commit at the tip of the feature to apply correctly to the sub
branch, even if it is fixing up the most-recent commit in that part.
This change update the documentation and builtin to accept the
--update-refs option as well as updating the todo file with the
'update-ref' commands. Tests are added to ensure that these todo
commands are added in the correct locations.
This change does _not_ include the actual behavior of tracking the
updated refs and writing the new ref values at the end of the rebase
process. That is deferred to a later change.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add the boilerplate for an "update-ref" command in the sequencer. This
connects to the current no-op do_update_ref() which will be filled in
after more connections are created.
The syntax in the todo list will be "update-ref <ref-name>" to signal
that we should store the current commit as the value for updating
<ref-name> at the end of the rebase.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The branch_checked_out() helper helps commands like 'git branch' and
'git fetch' from overwriting refs that are currently checked out in
other worktrees.
A future update to 'git rebase' will introduce a new '--update-refs'
option which will update the local refs that point to commits that are
being rebased. To avoid collisions as the rebase completes, we want to
make the future data store for these refs to be considered by
branch_checked_out().
The data store is a plaintext file inside the 'rebase-merge' directory
for that worktree. The file lists refnames followed by two OIDs, each on
separate lines. The OIDs will be used to store the original values of
the refs and the to-be-written values as the rebase progresses, but can
be ignored at the moment.
Create a new sequencer_get_update_refs_state() method that parses this
file and populates a struct string_list with the ref-OID pairs. We can
then use this list to add to the current_checked_out_branches strmap
used by branch_checked_out().
To properly navigate to the rebase directory for a given worktree,
extract the static strbuf_worktree_gitdir() method to a public API
method.
We can test that this works without having Git write this file by
artificially creating one in our test script, at least until 'git rebase
--update-refs' is implemented and we can use it directly.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A typical "git revert" commit uses the full title of the original
commit in its title, and starts its body of the message with:
This reverts commit 8fa7f667cf61386257c00d6e954855cc3215ae91.
This does not encourage the best practice of describing not just
"what" (i.e. "Revert X" on the title says what we did) but "why"
(i.e. and it does not say why X was undesirable).
We can instead phrase this first line of the body to be more like
This reverts commit 8fa7f667 (do this and that, 2022-04-25)
so that the title does not have to be
Revert "do this and that"
We can instead use the title to describe "why" we are reverting the
original commit.
Introduce the "--reference" option to "git revert", and also the
revert.reference configuration variable, which defaults to false, to
tweak the title and the first line of the draft commit message for
when creating a "revert" commit.
When this option is in use, the first line of the pre-filled editor
buffer becomes a comment line that tells the user to say _why_. If
the user exits the editor without touching this line by mistake,
what we prepare to become the first line of the body, i.e. "This
reverts commit 8fa7f667 (do this and that, 2022-04-25)", ends up to
be the title of the resulting commit. This behaviour is designed to
help such a user to identify such a revert in "git log --oneline"
easily so that it can be further reworded with "git rebase -i" later.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The default_reflog parameter of create_autostash() is passed to
reset_head(). However as creating a stash does not involve updating
any refs the parameter is not used by reset_head(). Removing the
parameter from create_autostash() simplifies the callers.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "--preserve-merges" option of "git rebase" has been removed.
* js/retire-preserve-merges:
sequencer: restrict scope of a formerly public function
rebase: remove a no-longer-used function
rebase: stop mentioning the -p option in comments
rebase: remove obsolete code comment
rebase: drop the internal `rebase--interactive` command
git-svn: drop support for `--preserve-merges`
rebase: drop support for `--preserve-merges`
pull: remove support for `--rebase=preserve`
tests: stop testing `git rebase --preserve-merges`
remote: warn about unhandled branch.<name>.rebase values
t5520: do not use `pull.rebase=preserve`
The code to re-read the edited todo list in "git rebase -i" was
made more robust.
* pw/rebase-reread-todo-after-editing:
rebase: fix todo-list rereading
sequencer.c: factor out a function
Move various *_INIT macros to use designated initializers. This helps
readability. I've only picked those leftover macros that were not
touched by another in-flight series of mine which changed others, but
also how initialization was done.
In the case of SUBMODULE_ALTERNATE_SETUP_INIT I've left an explicit
initialization of "error_mode", even though
SUBMODULE_ALTERNATE_ERROR_IGNORE itself is defined as "0". Let's not
peek under the hood and assume that enum fields we know the value of
will stay at "0".
The change to "TESTSUITE_INIT" in "t/helper/test-run-command.c" was
part of an earlier on-list version[1] of c90be786da (test-tool
run-command: fix flip-flop init pattern, 2021-09-11).
1. https://lore.kernel.org/git/patch-1.1-0aa4523ab6e-20210909T130849Z-avarab@gmail.com/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
54fd3243da ("rebase -i: reread the todo list if `exec` touched it",
2017-04-26) sought to reread the todo list after running an exec
command only if it had been changed. To accomplish this it checks the
stat data of the todo list after running an exec command to see if it
has changed. Unfortunately there are two problems, firstly the
implementation is buggy we actually reread the list after each exec
which is quadratic in the number of commit lookups and secondly the
design is predicated on using nanosecond time stamps which are not the
default.
The implementation bug stems from the fact that we write a new todo
list to disk before running each command but do not update the stat
data to reflect this[1].
The design problem is that it is possible for the user to edit the
todo list without changing its size or inode which means we have to
rely on the mtime to tell us if it has changed. Unfortunately unless
git is built with USE_NSEC it is possible for the original and edited
list to share the same mtime.
Ideally "git rebase --edit-todo" would set a flag that we would then
check in sequencer.c. Unfortunately this is approach will not work as
there are scripts in the wild that write to the todo list directly
without running "git rebase --edit-todo". Instead of relying on stat
data this patch simply reads the possibly edited todo list and
compares it to the original with memcmp(). This is much faster than
reparsing the todo list each time. This patch reduces the time to run
git rebase -r -xtrue v2.32.0~100 v2.32.0
which runs 419 exec commands by 6.6%. For comparison fixing the
implementation bug in stat based approach reduces the time by a
further 1.4% and is indistinguishable from never rereading the todo
list.
[1] https://lore.kernel.org/git/20191125131833.GD23183@szeder.dev/
Reported-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The function to add the `exec` commands to the todo list only needed to
be public API because it was not only used internally by the sequencer,
but also by `git rebase --preserve-merges`.
Now that that mode has been removed, we no longer need that function to
be scoped publicly.
Helped-by: Alban Gruin <alban.gruin@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Reviewed-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Silently skipping commits when rebasing with --no-reapply-cherry-picks
(currently the default behavior) can cause user confusion. Issue
warnings when this happens, as well as advice on how to preserve the
skipped commits.
These warnings and advice are displayed only when using the (default)
"merge" rebase backend.
Update the git-rebase docs to mention the warnings and advice.
Signed-off-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
save_opts() should save any non-default values. It was intended to do
this, but since most options in struct replay_opts default to 0, it only
saved non-zero values. Unfortunately, this does not always work for
options.edit. Roughly speaking, options.edit had a default value of 0
for cherry-pick but a default value of 1 for revert. Make save_opts()
record a value whenever it differs from the default.
options.edit was also overly simplistic; we had more than two cases.
The behavior that previously existed was as follows:
Non-conflict commits Right after Conflict
revert Edit iff isatty(0) Edit (ignore isatty(0))
cherry-pick No edit See above
Specify --edit Edit (ignore isatty(0)) See above
Specify --no-edit (*) See above
(*) Before stopping for conflicts, No edit is the behavior. After
stopping for conflicts, the --no-edit flag is not saved so see
the first two rows.
However, the expected behavior is:
Non-conflict commits Right after Conflict
revert Edit iff isatty(0) Edit iff isatty(0)
cherry-pick No edit Edit iff isatty(0)
Specify --edit Edit (ignore isatty(0)) Edit (ignore isatty(0))
Specify --no-edit No edit No edit
In order to get the expected behavior, we need to change options.edit
to a tri-state: unspecified, false, or true. When specified, we follow
what it says. When unspecified, we need to check whether the current
commit being created is resolving a conflict as well as consulting
options.action and isatty(0). While at it, add a should_edit() utility
function that compresses options.edit down to a boolean based on the
additional information for the non-conflict case.
continue_single_pick() is the function responsible for resuming after
conflict cases, regardless of whether there is one commit being picked
or many. Make this function stop assuming edit behavior in all cases,
so that it can correctly handle !isatty(0) and specific requests to not
edit the commit message.
Reported-by: Renato Botelho <garga@freebsd.org>
Signed-off-by: Elijah Newren <newren@gmail.com>
Reviewed-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Preparation for a new merge strategy.
* en/merge-ort-api-null-impl:
merge,rebase,revert: select ort or recursive by config or environment
fast-rebase: demonstrate merge-ort's API via new test-tool command
merge-ort-wrappers: new convience wrappers to mimic the old merge API
merge-ort: barebones API of new merge strategy with empty implementation
"git rebase -i" did not store ORIG_HEAD correctly.
* pw/rebase-i-orig-head:
rebase -i: simplify get_revision_ranges()
rebase -i: use struct object_id when writing state
rebase -i: use struct object_id rather than looking up commit
rebase -i: stop overwriting ORIG_HEAD buffer
Rather than passing a string around pass the struct object_id that the
string was created from call oid_hex() when we write the file.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We already have a struct object_id containing the oid that we want to
set ORIG_HEAD to so use that rather than converting it to a string and
then calling get_oid() on that string.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Allow the testsuite to run where it treats requests for "recursive" or
the default merge algorithm via consulting the environment variable
GIT_TEST_MERGE_ALGORITHM which is expected to either be "recursive" (the
old traditional algorithm) or "ort" (the new algorithm).
Also, allow folks to pick the new algorithm via config setting. It
turns out builtin/merge.c already had a way to allow users to specify a
different default merge algorithm: pull.twohead. Rather odd
configuration name (especially to be in the 'pull' namespace rather than
'merge') but it's there. Add that same configuration to rebase,
cherry-pick, and revert.
This required updating the various callsites that called merge_trees()
or merge_recursive() to conditionally call the new API, so this serves
as another demonstration of what the new API looks and feels like.
There are almost certainly some callsites that have not yet been
modified to work with the new merge algorithm, but this represents the
ones that I have been testing with thus far.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
For the --committer-date-is-author-date option of git-am and git-rebase,
we format the committer ident, then re-parse it to find the name and
email, and then feed those back to fmt_ident().
We can simplify this by handling it all at the time of the fmt_ident()
call. We pass in the appropriate getenv() results, and if they're not
present, then our WANT_COMMITTER_IDENT flag tells fmt_ident() to fill in
the appropriate value from the config. Which is exactly what
git_committer_ident() was doing under the hood.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git rebase -i" learns a bit more options.
* pw/rebase-i-more-options:
t3436: do not run git-merge-recursive in dashed form
rebase: add --reset-author-date
rebase -i: support --ignore-date
rebase -i: support --committer-date-is-author-date
am: stop exporting GIT_COMMITTER_DATE
rebase -i: add --ignore-whitespace flag
Rebase is implemented with two different backends - 'apply' and
'merge' each of which support a different set of options. In
particular the apply backend supports a number of options implemented
by 'git am' that are not implemented in the merge backend. This means
that the available options are different depending on which backend is
used which is confusing. This patch adds support for the --ignore-date
option to the merge backend. This option uses the current time as the
author date rather than reusing the original author date when
rewriting commits. We take care to handle the combination of
--ignore-date and --committer-date-is-author-date in the same way as
the apply backend.
Original-patch-by: Rohit Ashiwal <rohit.ashiwal265@gmail.com>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Rebase is implemented with two different backends - 'apply' and
'merge' each of which support a different set of options. In
particular the apply backend supports a number of options implemented
by 'git am' that are not implemented in the merge backend. This means
that the available options are different depending on which backend is
used which is confusing. This patch adds support for the
--committer-date-is-author-date option to the merge backend. This
option uses the author date of the commit that is being rewritten as
the committer date when the new commit is created.
Original-patch-by: Rohit Ashiwal <rohit.ashiwal265@gmail.com>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Allow "git rebase" to reapply all local commits, even if the may be
already in the upstream, without checking first.
* jt/rebase-allow-duplicate:
rebase --merge: optionally skip upstreamed commits
"git rebase" (again) learns to honor "--no-keep-empty", which lets
the user to discard commits that are empty from the beginning (as
opposed to the ones that become empty because of rebasing). The
interactive rebase also marks commits that are empty in the todo.
* en/rebase-no-keep-empty:
rebase: fix an incompatible-options error message
rebase: reinstate --no-keep-empty
rebase -i: mark commits that begin empty in todo editor
When rebasing against an upstream that has had many commits since the
original branch was created:
O -- O -- ... -- O -- O (upstream)
\
-- O (my-dev-branch)
it must read the contents of every novel upstream commit, in addition to
the tip of the upstream and the merge base, because "git rebase"
attempts to exclude commits that are duplicates of upstream ones. This
can be a significant performance hit, especially in a partial clone,
wherein a read of an object may end up being a fetch.
Add a flag to "git rebase" to allow suppression of this feature. This
flag only works when using the "merge" backend.
This flag changes the behavior of sequencer_make_script(), called from
do_interactive_rebase() <- run_rebase_interactive() <-
run_specific_rebase() <- cmd_rebase(). With this flag, limit_list()
(indirectly called from sequencer_make_script() through
prepare_revision_walk()) will no longer call cherry_pick_list(), and
thus PATCHSAME is no longer set. Refraining from setting PATCHSAME both
means that the intermediate commits in upstream are no longer read (as
shown by the test) and means that no PATCHSAME-caused skipping of
commits is done by sequencer_make_script(), either directly or through
make_script_with_merges().
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commit d48e5e21da ("rebase (interactive-backend): make --keep-empty the
default", 2020-02-15) turned --keep-empty (for keeping commits which
start empty) into the default. The logic underpinning that commit was:
1) 'git commit' errors out on the creation of empty commits without an
override flag
2) Once someone determines that the override is worthwhile, it's
annoying and/or harmful to required them to take extra steps in
order to keep such commits around (and to repeat such steps with
every rebase).
While the logic on which the decision was made is sound, the result was
a bit of an overcorrection. Instead of jumping to having --keep-empty
being the default, it jumped to making --keep-empty the only available
behavior. There was a simple workaround, though, which was thought to
be good enough at the time. People could still drop commits which
started empty the same way the could drop any commits: by firing up an
interactive rebase and picking out the commits they didn't want from the
list. However, there are cases where external tools might create enough
empty commits that picking all of them out is painful. As such, having
a flag to automatically remove start-empty commits may be beneficial.
Provide users a way to drop commits which start empty using a flag that
existed for years: --no-keep-empty. Interpret --keep-empty as
countermanding any previous --no-keep-empty, but otherwise leaving
--keep-empty as the default.
This might lead to some slight weirdness since commands like
git rebase --empty=drop --keep-empty
git rebase --empty=keep --no-keep-empty
look really weird despite making perfect sense (the first will drop
commits which become empty, but keep commits that started empty; the
second will keep commits which become empty, but drop commits which
started empty). However, --no-keep-empty was named years ago and we are
predominantly keeping it for backward compatibility; also we suspect it
will only be used rarely since folks already have a simple way to drop
commits they don't want with an interactive rebase.
Reported-by: Bryan Turner <bturner@atlassian.com>
Reported-by: Sami Boukortt <sami@boukortt.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Split apply_save_autostash() into apply_autostash_oid() and
apply_save_autostash() where the former operates on an OID string and
the latter reads the OID from a file before passing it into
apply_save_autostash_oid().
This function is required for a future commmit which will rely on being
able to apply an autostash whose OID is stored as a string.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Extract common functionality of apply_autostash() into
apply_save_autostash() and use it to implement save_autostash(). This
function will be used in a future commit.
The difference between save_autostash() and apply_autostash() is that
the former does not try to apply the stash. It skips that step and
just stores the created entry in the stash reflog.
This is useful in the case where we abort an operation when an autostash
is present but we don't want to dirty the worktree with the application
of the stash. For example, in a future commit, we will implement
`git merge --autostash`. Since merges can be aborted using
`git reset --hard`, we'd make use of save_autostash() to save the
autostash entry instead of applying it to the worktree thus keeping the
worktree undirtied.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Lib-ify the autostash code by extracting perform_autostash() from rebase
into sequencer. In a future commit, this will be used to implement
`--autostash` in other builtins.
This patch is best viewed with `--color-moved`.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The apply_autostash() function in builtin/rebase.c is similar enough to
the apply_autostash() function in sequencer.c that they are almost
interchangeable, except for the type of arg they accept. Make the
sequencer.c version extern and use it in rebase.
The rebase version was introduced in 6defce2b02 (builtin rebase: support
`--autostash` option, 2018-09-04) as part of the shell to C conversion.
It opted to duplicate the function because, at the time, there was
another in-progress project converting interactive rebase from shell to
C as well and they did not want to clash with them by refactoring
sequencer.c version of apply_autostash(). Since both efforts are long
done, we can freely combine them together now.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The function read_oneliner() is a generally useful util function.
Instead of hiding it as a static function within sequencer.c, extern it
so that it can be reused by others.
This patch is best viewed with --color-moved.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The mechanism to prevent "git commit" from making an empty commit
or amending during an interrupted cherry-pick was broken during the
rewrite of "git rebase" in C, which has been corrected.
* pw/advise-rebase-skip:
commit: give correct advice for empty commit during a rebase
commit: encapsulate determine_whence() for sequencer
commit: use enum value for multiple cherry-picks
sequencer: write CHERRY_PICK_HEAD for reword and edit
cherry-pick: check commit error messages
cherry-pick: add test for `--skip` advice in `git commit`
t3404: use test_cmp_rev
"git rebase" has learned to use the merge backend (i.e. the
machinery that drives "rebase -i") by default, while allowing
"--apply" option to use the "apply" backend (e.g. the moral
equivalent of "format-patch piped to am"). The rebase.backend
configuration variable can be set to customize.
* en/rebase-backend:
rebase: rename the two primary rebase backends
rebase: change the default backend from "am" to "merge"
rebase: make the backend configurable via config setting
rebase tests: repeat some tests using the merge backend instead of am
rebase tests: mark tests specific to the am-backend with --am
rebase: drop '-i' from the reflog for interactive-based rebases
git-prompt: change the prompt for interactive-based rebases
rebase: add an --am option
rebase: move incompatibility checks between backend options a bit earlier
git-rebase.txt: add more details about behavioral differences of backends
rebase: allow more types of rebases to fast-forward
t3432: make these tests work with either am or merge backends
rebase: fix handling of restrict_revision
rebase: make sure to pass along the quiet flag to the sequencer
rebase, sequencer: remove the broken GIT_QUIET handling
t3406: simplify an already simple test
rebase (interactive-backend): fix handling of commits that become empty
rebase (interactive-backend): make --keep-empty the default
t3404: directly test the behavior of interest
git-rebase.txt: update description of --allow-empty-message
As established in the previous commit and commit b00bf1c9a8
(git-rebase: make --allow-empty-message the default, 2018-06-27), the
behavior for rebase with different backends in various edge or corner
cases is often more happenstance than design. This commit addresses
another such corner case: commits which "become empty".
A careful reader may note that there are two types of commits which would
become empty due to a rebase:
* [clean cherry-pick] Commits which are clean cherry-picks of upstream
commits, as determined by `git log --cherry-mark ...`. Re-applying
these commits would result in an empty set of changes and a
duplicative commit message; i.e. these are commits that have
"already been applied" upstream.
* [become empty] Commits which are not empty to start, are not clean
cherry-picks of upstream commits, but which still become empty after
being rebased. This happens e.g. when a commit has changes which
are a strict subset of the changes in an upstream commit, or when
the changes of a commit can be found spread across or among several
upstream commits.
Clearly, in both cases the changes in the commit in question are found
upstream already, but the commit message may not be in the latter case.
When cherry-mark can determine a commit is already upstream, then
because of how cherry-mark works this means the upstream commit message
was about the *exact* same set of changes. Thus, the commit messages
can be assumed to be fully interchangeable (and are in fact likely to be
completely identical). As such, the clean cherry-pick case represents a
case when there is no information to be gained by keeping the extra
commit around. All rebase types have always dropped these commits, and
no one to my knowledge has ever requested that we do otherwise.
For many of the become empty cases (and likely even most), we will also
be able to drop the commit without loss of information -- but this isn't
quite always the case. Since these commits represent cases that were
not clean cherry-picks, there is no upstream commit message explaining
the same set of changes. Projects with good commit message hygiene will
likely have the explanation from our commit message contained within or
spread among the relevant upstream commits, but not all projects run
that way. As such, the commit message of the commit being rebased may
have reasoning that suggests additional changes that should be made to
adapt to the new base, or it may have information that someone wants to
add as a note to another commit, or perhaps someone even wants to create
an empty commit with the commit message as-is.
Junio commented on the "become-empty" types of commits as follows[1]:
WRT a change that ends up being empty (as opposed to a change that
is empty from the beginning), I'd think that the current behaviour
is desireable one. "am" based rebase is solely to transplant an
existing history and want to stop much less than "interactive" one
whose purpose is to polish a series before making it publishable,
and asking for confirmation ("this has become empty--do you want to
drop it?") is more appropriate from the workflow point of view.
[1] https://lore.kernel.org/git/xmqqfu1fswdh.fsf@gitster-ct.c.googlers.com/
I would simply add that his arguments for "am"-based rebases actually
apply to all non-explicitly-interactive rebases. Also, since we are
stating that different cases should have different defaults, it may be
worth providing a flag to allow users to select which behavior they want
for these commits.
Introduce a new command line flag for selecting the desired behavior:
--empty={drop,keep,ask}
with the definitions:
drop: drop commits which become empty
keep: keep commits which become empty
ask: provide the user a chance to interact and pick what to do with
commits which become empty on a case-by-case basis
In line with Junio's suggestion, if the --empty flag is not specified,
pick defaults as follows:
explicitly interactive: ask
otherwise: drop
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Different rebase backends have different treatment for commits which
start empty (i.e. have no changes relative to their parent), and the
--keep-empty option was added at some point to allow adjusting behavior.
The handling of commits which start empty is actually quite similar to
commit b00bf1c9a8 (git-rebase: make --allow-empty-message the default,
2018-06-27), which pointed out that the behavior for various backends is
often more happenstance than design. The specific change made in that
commit is actually quite relevant as well and much of the logic there
directly applies here.
It makes a lot of sense in 'git commit' to error out on the creation of
empty commits, unless an override flag is provided. However, once
someone determines that there is a rare case that merits using the
manual override to create such a commit, it is somewhere between
annoying and harmful to have to take extra steps to keep such
intentional commits around. Granted, empty commits are quite rare,
which is why handling of them doesn't get considered much and folks tend
to defer to existing (accidental) behavior and assume there was a reason
for it, leading them to just add flags (--keep-empty in this case) that
allow them to override the bad defaults. Fix the interactive backend so
that --keep-empty is the default, much like we did with
--allow-empty-message. The am backend should also be fixed to have
--keep-empty semantics for commits that start empty, but that is not
included in this patch other than a testcase documenting the failure.
Note that there was one test in t3421 which appears to have been written
expecting --keep-empty to not be the default as correct behavior. This
test was introduced in commit 00b8be5a4d ("add tests for rebasing of
empty commits", 2013-06-06), which was part of a series focusing on
rebase topology and which had an interesting original cover letter at
https://lore.kernel.org/git/1347949878-12578-1-git-send-email-martinvonz@gmail.com/
which noted
Your input especially appreciated on whether you agree with the
intent of the test cases.
and then went into a long example about how one of the many tests added
had several questions about whether it was correct. As such, I believe
most the tests in that series were about testing rebase topology with as
many different flags as possible and were not trying to state in general
how those flags should behave otherwise.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Allow the rebase.missingCommitsCheck configuration to kick in when
"rebase --edit-todo" and "rebase --continue" restarts the procedure.
* ag/edit-todo-drop-check:
rebase-interactive: warn if commit is dropped with `rebase --edit-todo'
sequencer: move check_todo_list_from_file() to rebase-interactive.c
"git rebase -i" (and friends) used to unnecessarily check out the
tip of the branch to be rebased, which has been corrected.
* ag/rebase-avoid-unneeded-checkout:
rebase -i: stop checking out the tip of the branch to rebase
When set to "warn" or "error", `rebase.missingCommitsCheck' would make
`rebase -i' warn if the user removed commits from the todo list to
prevent mistakes. Unfortunately, `rebase --edit-todo' and `rebase
--continue' don't take it into account.
This adds the ability for `rebase --edit-todo' and `rebase --continue'
to check if commits were dropped by the user. As both edit_todo_list()
and complete_action() parse the todo list and check for dropped commits,
the code doing so in the latter is removed to reduce duplication.
`edit_todo_list_advice' is removed from sequencer.c as it is no longer
used there.
This changes when a backup of the todo list is made. Until now, it was
saved only once, before the initial edit. Now, it is also made if the
original todo list has no errors or no dropped commits. Thus, the
backup should be error-free. Without this, sequencer_continue()
(`rebase --continue') could only compare the current todo list against
the original, unedited list. Before this change, this file was only
used by edit_todo_list() and `rebase -p' to create the backup before
the initial edit, and check_todo_list_from_file(), only used by
`rebase -p' to check for dropped commits after its own initial edit.
If the edited list has an error, a file, `dropped', is created to
report the issue. Otherwise, it is deleted. Usually, the edited list
is compared against the list before editing, but if this file exists,
it will be compared to the backup. Also, if the file exists,
sequencer_continue() checks the list for dropped commits. If the
check was performed every time, it would fail when resuming a rebase
after resolving a conflict, as the backup will contain commits that
were picked, but they will not be in the new list. It's safe to
ignore this check if `dropped' does not exist, because that means that
no errors were found at the last edition, so any missing commits here
have already been picked.
Five tests are added to t3404. The tests for
`rebase.missingCommitsCheck = warn' and `rebase.missingCommitsCheck =
error' have a similar structure. First, we start a rebase with an
incorrect command on the first line. Then, we edit the todo list,
removing the first and the last lines. This demonstrates that
`--edit-todo' notices dropped commits, but not when the command is
incorrect. Then, we restore the original todo list, and edit it to
remove the last line. This demonstrates that if we add a commit after
the initial edit, then remove it, `--edit-todo' will notice that it
has been dropped. Then, the actual rebase takes place. In the third
test, it is also checked that `--continue' will refuse to resume the
rebase if commits were dropped. The fourth test checks that no errors
are raised when resuming a rebase after resolving a conflict, the fifth
checks that no errors are raised when editing the todo list after
pausing the rebase.
Signed-off-by: Alban Gruin <alban.gruin@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The message contained in `edit_todo_list_advice' (sequencer.c) is
printed after the initial edit of the todo list if it can't be parsed or
if commits were dropped. This is done either in complete_action() for
`rebase -i', or in check_todo_list_from_file() for `rebase -p'.
Since we want to add this check when editing the list, we also want to
use this message from edit_todo_list() (rebase-interactive.c). To this
end, check_todo_list_from_file() is moved to rebase-interactive.c, and
`edit_todo_list_advice' is copied there. In the next commit,
complete_action() will stop using it, and `edit_todo_list_advice' will
be removed from sequencer.c.
Signed-off-by: Alban Gruin <alban.gruin@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
One of the first things done when using a sequencer-based
rebase (ie. `rebase -i', `rebase -r', or `rebase -m') is to make a todo
list. This requires knowledge of the commit range to rebase. To get
the oid of the last commit of the range, the tip of the branch to rebase
is checked out with prepare_branch_to_be_rebased(), then the oid of the
head is read. After this, the tip of the branch is not even modified.
The `am' backend, on the other hand, does not check out the branch.
On big repositories, it's a performance penalty: with `rebase -i', the
user may have to wait before editing the todo list while git is
extracting the branch silently, and "quiet" rebases will be slower than
`am'.
Since we already have the oid of the tip of the branch in
`opts->orig_head', it's useless to switch to this commit.
This removes the call to prepare_branch_to_be_rebased() in
do_interactive_rebase(), and adds a `orig_head' parameter to
get_revision_ranges(). prepare_branch_to_be_rebased() is removed as it
is no longer used.
This introduces a visible change: as we do not switch on the tip of the
branch to rebase, no reflog entry is created at the beginning of the
rebase for it.
Unscientific performance measurements, performed on linux.git, are as
follow:
Before this patch:
$ time git rebase -m --onto v4.18 463fa44eec2fef50~ 463fa44eec2fef50
real 0m8,940s
user 0m6,830s
sys 0m2,121s
After this patch:
$ time git rebase -m --onto v4.18 463fa44eec2fef50~ 463fa44eec2fef50
real 0m1,834s
user 0m0,916s
sys 0m0,206s
Reported-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Alban Gruin <alban.gruin@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This reverts commit 5d9324e0f4, reversing
changes made to c58ae96fc4.
The topic turns out to be too buggy for real use.
cf. <f2fe7437-8a48-3315-4d3f-8d51fe4bb8f1@gmail.com>
"git rebase -i" learned a few options that are known by "git
rebase" proper.
* ra/rebase-i-more-options:
rebase -i: finishing touches to --reset-author-date
rebase: add --reset-author-date
rebase -i: support --ignore-date
sequencer: rename amend_author to author_to_rename
rebase -i: support --committer-date-is-author-date
sequencer: allow callers of read_author_script() to ignore fields
rebase -i: add --ignore-whitespace flag
Working out which command wants to create a commit requires detailed
knowledge of the sequencer internals and that knowledge is going to
increase in subsequent commits. With that in mind lets encapsulate that
knowledge in sequencer.c rather than spreading it into builtin/commit.c.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"rebase -i" ceased to run post-commit hook by mistake in an earlier
update, which has been corrected.
* pw/post-commit-from-sequencer:
sequencer: run post-commit hook
move run_commit_hook() to libgit and use it there
sequencer.h fix placement of #endif
t3404: remove uneeded calls to set_fake_editor
t3404: set $EDITOR in subshell
t3404: remove unnecessary subshell
rebase am already has this flag to "lie" about the author date
by changing it to the committer (current) date. Let's add the same
for interactive machinery.
Signed-off-by: Rohit Ashiwal <rohit.ashiwal265@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
rebase am already has this flag to "lie" about the committer date
by changing it to the author date. Let's add the same for
interactive machinery.
Signed-off-by: Rohit Ashiwal <rohit.ashiwal265@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commit 65850686cf ("rebase -i: rewrite write_basic_state() in C",
2018-08-28) accidentially added new function declarations after
the #endif at the end of the include guard.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
