Band-aid fixes for two fallouts from switching the default "rebase"
backend.
* en/rebase-backend:
git-rebase.txt: highlight backend differences with commit rewording
sequencer: clear state upon dropping a become-empty commit
i18n: unmark a message in rebase.c
Commit v2.25.0-4-ge98c4269c8 (rebase (interactive-backend): fix handling
of commits that become empty, 2020-02-15) marked "{drop,keep,ask}" for
translation, but this message should not be changed.
Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git rebase BASE BRANCH" rebased/updated the tip of BRANCH and
checked it out, even when the BRANCH is checked out in a different
worktree. This has been corrected.
* es/do-not-let-rebase-switch-to-protected-branch:
rebase: refuse to switch to branch already checked out elsewhere
t3400: make test clean up after itself
"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
When `options.switch_to' is set, `options.orig_head' is populated right
after with the object name the ref/commit argument points at.
Therefore, there is no need to parse `switch_to' again.
Signed-off-by: Alban Gruin <alban.gruin@gmail.com>
Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The invocation "git rebase <upstream> <branch>" switches to <branch>
before performing the rebase operation. However, unlike git-switch,
git-checkout, and git-worktree which all refuse to switch to a branch
that is already checked out in some other worktree, git-rebase switches
to <branch> unconditionally. Curb this careless behavior by making
git-rebase also refuse to switch to a branch checked out elsewhere.
Reported-by: Mike Hommey <mh@glandium.org>
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Two related changes, with separate rationale for each:
Rename the 'interactive' backend to 'merge' because:
* 'interactive' as a name caused confusion; this backend has been used
for many kinds of non-interactive rebases, and will probably be used
in the future for more non-interactive rebases than interactive ones
given that we are making it the default.
* 'interactive' is not the underlying strategy; merging is.
* the directory where state is stored is not called
.git/rebase-interactive but .git/rebase-merge.
Rename the 'am' backend to 'apply' because:
* Few users are familiar with git-am as a reference point.
* Related to the above, the name 'am' makes sentences in the
documentation harder for users to read and comprehend (they may read
it as the verb from "I am"); avoiding this difficult places a large
burden on anyone writing documentation about this backend to be very
careful with quoting and sentence structure and often forces
annoying redundancy to try to avoid such problems.
* Users stumble over pronunciation ("am" as in "I am a person not a
backend" or "am" as in "the first and thirteenth letters in the
alphabet in order are "A-M"); this may drive confusion when one user
tries to explain to another what they are doing.
* While "am" is the tool driving this backend, the tool driving git-am
is git-apply, and since we are driving towards lower-level tools
for the naming of the merge backend we may as well do so here too.
* The directory where state is stored has never been called
.git/rebase-am, it was always called .git/rebase-apply.
For all the reasons listed above:
* Modify the documentation to refer to the backends with the new names
* Provide a brief note in the documentation connecting the new names
to the old names in case users run across the old names anywhere
(e.g. in old release notes or older versions of the documentation)
* Change the (new) --am command line flag to --apply
* Rename some enums, variables, and functions to reinforce the new
backend names for us as well.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A large variety of rebase types are supported by the interactive
machinery, not just the explicitly interactive ones. These all share
the same code and write the same reflog messages, but the "-i" moniker
in those messages doesn't really have much meaning. It also becomes
somewhat distracting once we switch the default from the am-backend to
the interactive one. Just remove the "-i" from these messages.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Currently, this option doesn't do anything except error out if any
options requiring the interactive-backend are also passed. However,
when we make the default backend configurable later in this series, this
flag will provide a way to override the config setting.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the past, we dis-allowed rebases using the interactive backend from
performing a fast-forward to short-circuit the rebase operation. This
made sense for explicitly interactive rebases and some implicitly
interactive rebases, but certainly became overly stringent when the
merge backend was re-implemented via the interactive backend.
Just as the am-based rebase has always had to disable the fast-forward
based on a variety of conditions or flags (e.g. --signoff, --whitespace,
etc.), we need to do the same but now with a few more options. However,
continuing to use REBASE_FORCE for tracking this is problematic because
the interactive backend used it for a different purpose. (When
REBASE_FORCE wasn't set, the interactive backend would not fast-forward
the whole series but would fast-forward individual "pick" commits at the
beginning of the todo list, and then a squash or something would cause
it to start generating new commits.) So, introduce a new
allow_preemptive_ff flag contained within cmd_rebase() and use it to
track whether we are going to allow a pre-emptive fast-forward that
short-circuits the whole rebase.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
restrict_revision in the original shell script was an excluded revision
range. It is also treated that way by the am-backend. In the
conversion from shell to C (see commit 6ab54d17be ("rebase -i:
implement the logic to initialize $revisions in C", 2018-08-28)), the
interactive-backend accidentally treated it as a positive revision
rather than a negated one.
This was missed as there were no tests in the testsuite that tested an
interactive rebase with fork-point behavior.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The GIT_QUIET environment variable was used to signal the non-am
backends that the rebase should perform quietly. The preserve-merges
backend does not make use of the quiet flag anywhere (other than to
write out its state whenever it writes state), and this mechanism was
broken in the conversion from shell to C. Since this environment
variable was specifically designed for scripts and the only backend that
would still use it is no longer a script, just gut this code.
A subsequent commit will fix --quiet for the interactive/merge backend
in a different way.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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>
"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
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>
Commit b00bf1c9a8 ("git-rebase: make --allow-empty-message the
default", 2018-06-27) made --allow-empty-message the default and thus
turned --allow-empty-message into a no-op but did not update the
documentation to reflect this. Update the documentation now, and hide
the option from the normal -h output since it is not useful.
Signed-off-by: Elijah Newren <newren@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 --signoff" stopped working when the command was written
in C, which has been corrected.
* en/rebase-signoff-fix:
rebase: fix saving of --signoff state for am-based rebases
This was an error introduced in the conversion from shell in commit
21853626ea ("built-in rebase: call `git am` directly", 2019-01-18),
which was noticed by a random browsing of the code.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git rebase" did not work well when format.useAutoBase
configuration variable is set, which has been corrected.
* dl/rebase-with-autobase:
rebase: fix format.useAutoBase breakage
format-patch: teach --no-base
t4014: use test_config()
format-patch: fix indentation
t3400: demonstrate failure with format.useAutoBase
Reduce unnecessary reading of state variables back from the disk
during sequencer operation.
* ag/sequencer-todo-updates:
sequencer: directly call pick_commits() from complete_action()
rebase: fill `squash_onto' in get_replay_opts()
sequencer: move the code writing total_nr on the disk to a new function
sequencer: update `done_nr' when skipping commands in a todo list
sequencer: update `total_nr' when adding an item to a todo list
"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
With `format.useAutoBase = true`, running rebase resulted in an
error:
fatal: failed to get upstream, if you want to record base commit automatically,
please use git branch --set-upstream-to to track a remote branch.
Or you could specify base commit by --base=<base-commit-id> manually
error:
git encountered an error while preparing the patches to replay
these revisions:
ede2467cdedc63784887b587a61c36b7850ebfac..d8f581194799ae29bf5fa72a98cbae98a1198b12
As a result, git cannot rebase them.
Fix this by always passing `--no-base` to format-patch from rebase so
that the effect of `format.useAutoBase` is negated.
Reported-by: Christian Biesinger <cbiesinger@google.com>
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Clarify the way the `--reset-author-date` option is described,
and mark its usage string translatable.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When sequencer_continue() is called by complete_action(), `opts' has
been filled by get_replay_opts(). Currently, it does not initialise the
`squash_onto' field (used by the `--root' mode), only
read_populate_opts() does. It’s not a problem yet since
sequencer_continue() calls it before pick_commits(), but it would lead
to incorrect results once complete_action() is modified to call
pick_commits() directly.
Let’s change that.
Signed-off-by: Alban Gruin <alban.gruin@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git rebase --preserve-merges" has been marked as deprecated; this
release stops advertising it in the "git rebase -h" output.
* js/rebase-deprecate-preserve-merges:
rebase: hide --preserve-merges option
The previous commit introduced --ignore-date flag to interactive
rebase, but the name is actually very vague in context of rebase -i
since there are two dates we can work with. Add an alias to convey
the precise purpose.
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 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>
There are two backends available for rebasing, viz, the am and the
interactive. Naturally, there shall be some features that are
implemented in one but not in the other. One such flag is
--ignore-whitespace which indicates merge mechanism to treat lines
with only whitespace changes as unchanged. Wire the interactive
rebase to also understand the --ignore-whitespace flag by
translating it to -Xignore-space-change.
Signed-off-by: Rohit Ashiwal <rohit.ashiwal265@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since --preserve-merges has been deprecated in favour of
--rebase-merges, mark this option as hidden so it no longer shows up in
the usage and completions.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git rebase --autostash <upstream> <branch>", when <branch> is
different from the current branch, incorrectly moved the tip of the
current branch, which has been corrected.
* bw/rebase-autostash-keep-current-branch:
builtin/rebase.c: Remove pointless message
builtin/rebase.c: make sure the active branch isn't moved when autostashing
"git rebase --keep-base <upstream>" tries to find the original base
of the topic being rebased and rebase on top of that same base,
which is useful when running the "git rebase -i" (and its limited
variant "git rebase -x").
The command also has learned to fast-forward in more cases where it
can instead of replaying to recreate identical commits.
* dl/rebase-i-keep-base:
rebase: teach rebase --keep-base
rebase tests: test linear branch topology
rebase: fast-forward --fork-point in more cases
rebase: fast-forward --onto in more cases
rebase: refactor can_fast_forward into goto tower
t3432: test for --no-ff's interaction with fast-forward
t3432: distinguish "noop-same" v.s. "work-same" in "same head" tests
t3432: test rebase fast-forward behavior
t3431: add rebase --fork-point tests
"git rebase --rebase-merges" learned to drive different merge
strategies and pass strategy specific options to them.
* js/rebase-r-strategy:
t3427: accelerate this test by using fast-export and fast-import
rebase -r: do not (re-)generate root commits with `--root` *and* `--onto`
t3418: test `rebase -r` with merge strategies
t/lib-rebase: prepare for testing `git rebase --rebase-merges`
rebase -r: support merge strategies other than `recursive`
t3427: fix another incorrect assumption
t3427: accommodate for the `rebase --merge` backend having been replaced
t3427: fix erroneous assumption
t3427: condense the unnecessarily repetitive test cases into three
t3427: move the `filter-branch` invocation into the `setup` case
t3427: simplify the `setup` test case significantly
t3427: add a clarifying comment
rebase: fold git-rebase--common into the -p backend
sequencer: the `am` and `rebase--interactive` scripts are gone
.gitignore: there is no longer a built-in `git-rebase--interactive`
t3400: stop referring to the scripted rebase
Drop unused git-rebase--am.sh
When doing 'git rebase --autostash <upstream> <master>' with a dirty worktree
a 'HEAD is now at ...' message is emitted, which is pointless as it refers to
the old active branch which isn't actually moved.
This commit removes the 'HEAD is now at...' message.
Signed-off-by: Ben Wijen <ben@wijen.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Consider the following scenario:
git checkout not-the-master
work work work
git rebase --autostash upstream master
Here 'rebase --autostash <upstream> <branch>' incorrectly moves the
active branch (not-the-master) to master (before the rebase).
The expected behavior: (58794775:/git-rebase.sh:526)
AUTOSTASH=$(git stash create autostash)
git reset --hard
git checkout master
git rebase upstream
git stash apply $AUTOSTASH
The actual behavior: (6defce2b:/builtin/rebase.c:1062)
AUTOSTASH=$(git stash create autostash)
git reset --hard master
git checkout master
git rebase upstream
git stash apply $AUTOSTASH
This commit reinstates the 'legacy script' behavior as introduced with
58794775: rebase: implement --[no-]autostash and rebase.autostash
Signed-off-by: Ben Wijen <ben@wijen.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A common scenario is if a user is working on a topic branch and they
wish to make some changes to intermediate commits or autosquash, they
would run something such as
git rebase -i --onto master... master
in order to preserve the merge base. This is useful when contributing a
patch series to the Git mailing list, one often starts on top of the
current 'master'. While developing the patches, 'master' is also
developed further and it is sometimes not the best idea to keep rebasing
on top of 'master', but to keep the base commit as-is.
In addition to this, a user wishing to test individual commits in a
topic branch without changing anything may run
git rebase -x ./test.sh master... master
Since rebasing onto the merge base of the branch and the upstream is
such a common case, introduce the --keep-base option as a shortcut.
This allows us to rewrite the above as
git rebase -i --keep-base master
and
git rebase -x ./test.sh --keep-base master
respectively.
Add tests to ensure --keep-base works correctly in the normal case and
fails when there are multiple merge bases, both in regular and
interactive mode. Also, test to make sure conflicting options cause
rebase to fail. While we're adding test cases, add a missing
set_fake_editor call to 'rebase -i --onto master...side'.
While we're documenting the --keep-base option, change an instance of
"merge-base" to "merge base", which is the consistent spelling.
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Before, when we rebased with a --fork-point invocation where the
fork-point wasn't empty, we would be setting options.restrict_revision.
The fast-forward logic would automatically declare that the rebase was
not fast-forwardable if it was set. However, this was painting with a
very broad brush.
Refine the logic so that we can fast-forward in the case where the
restricted revision is equal to the merge base, since we stop rebasing
at the merge base anyway.
Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Before, when we had the following graph,
A---B---C (master)
\
D (side)
running 'git rebase --onto master... master side' would result in D
being always rebased, no matter what. However, the desired behavior is
that rebase should notice that this is fast-forwardable and do that
instead.
Add detection to `can_fast_forward` so that this case can be detected
and a fast-forward will be performed. First of all, rewrite the function
to use gotos which simplifies the logic. Next, since the
options.upstream &&
!oidcmp(&options.upstream->object.oid, &options.onto->object.oid)
conditions were removed in `cmd_rebase`, we reintroduce a substitute in
`can_fast_forward`. In particular, checking the merge bases of
`upstream` and `head` fixes a failing case in t3416.
The abbreviated graph for t3416 is as follows:
F---G topic
/
A---B---C---D---E master
and the failing command was
git rebase --onto master...topic F topic
Before, Git would see that there was one merge base (C), and the merge
and onto were the same so it would incorrectly return 1, indicating that
we could fast-forward. This would cause the rebased graph to be 'ABCFG'
when we were expecting 'ABCG'.
With the additional logic, we detect that upstream and head's merge base
is F. Since onto isn't F, it means we're not rebasing the full set of
commits from master..topic. Since we're excluding some commits, a
fast-forward cannot be performed and so we correctly return 0.
Add '-f' to test cases that failed as a result of this change because
they were not expecting a fast-forward so that a rebase is forced.
Helped-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Before, can_fast_forward was written with an if-else statement. However,
in the future, we may be adding more termination cases which would lead
to deeply nested if statements.
Refactor to use a goto tower so that future cases can be easily
inserted.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When rebasing a complete commit history onto a given commit, it is
pretty obvious that the root commits should be rebased on top of said
given commit.
To test this, let's kill two birds with one stone and add a test case to
t3427-rebase-subtree.sh that not only demonstrates that this works, but
also that `git rebase -r` works with merge strategies now.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We already support merge strategies in the sequencer, but only for
`pick` commands.
With this commit, we now also support them in `merge` commands. The
approach is simple: if any merge strategy option is specified, or if any
merge strategy other than `recursive` is specified, we simply spawn the
`git merge` command. Otherwise, we handle the merge in-process just as
before.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The only remaining scripted part of `git rebase` is the
`--preserve-merges` backend. Meaning: there is little reason to keep the
"library of common rebase functions" as a separate file.
While moving the functions to `git-rebase--preserve-merges.sh`, we also
drop the `move_to_original_branch` function that is no longer used.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since 21853626ea (built-in rebase: call `git am` directly, 2019-01-18),
the built-in rebase already uses the built-in `git am` directly.
Now that d03ebd411c (rebase: remove the rebase.useBuiltin setting,
2019-03-18) even removed the scripted rebase, there is no longer any
user of `git-rebase--am.sh`, so let's just remove it.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
