Commit Graph

199 Commits

Author SHA1 Message Date
Elijah Newren
2ac0d6273f rebase: change the default backend from "am" to "merge"
The am-backend drops information and thus limits what we can do:

  * lack of full tree information from the original commits means we
    cannot do directory rename detection and warn users that they might
    want to move some of their new files that they placed in old
    directories to prevent their becoming orphaned.[1]
  * reduction in context from only having a few lines beyond those
    changed means that when context lines are non-unique we can apply
    patches incorrectly.[2]
  * lack of access to original commits means that conflict marker
    annotation has less information available.
  * the am backend has safety problems with an ill-timed interrupt.

Also, the merge/interactive backend have far more abilities, appear to
currently have a slight performance advantage[3] and have room for more
optimizations than the am backend[4] (and work is underway to take
advantage of some of those possibilities).

[1] https://lore.kernel.org/git/xmqqh8jeh1id.fsf@gitster-ct.c.googlers.com/
[2] https://lore.kernel.org/git/CABPp-BGiu2nVMQY_t-rnFR5GQUz_ipyEE8oDocKeO+h+t4Mn4A@mail.gmail.com/
[3] https://public-inbox.org/git/CABPp-BF=ev03WgODk6TMQmuNoatg2kiEe5DR__gJ0OTVqHSnfQ@mail.gmail.com/
[4] https://lore.kernel.org/git/CABPp-BGh7yW69QwxQb13K0HM38NKmQif3A6C6UULEKYnkEJ5vA@mail.gmail.com/

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-16 15:40:42 -08:00
Elijah Newren
8295ed690b rebase: make the backend configurable via config setting
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-16 15:40:42 -08:00
Elijah Newren
c2417d3af7 rebase: drop '-i' from the reflog for interactive-based rebases
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>
2020-02-16 15:40:42 -08:00
Elijah Newren
52eb738d6b rebase: add an --am option
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>
2020-02-16 15:40:42 -08:00
Elijah Newren
8af14f0859 rebase: move incompatibility checks between backend options a bit earlier
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-16 15:40:42 -08:00
Elijah Newren
befb89ce7c rebase: allow more types of rebases to fast-forward
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>
2020-02-16 15:40:42 -08:00
Elijah Newren
93122c985a rebase: fix handling of restrict_revision
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>
2020-02-16 15:40:42 -08:00
Elijah Newren
55d2b6d785 rebase: make sure to pass along the quiet flag to the sequencer
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-16 15:40:42 -08:00
Elijah Newren
8a997ed132 rebase, sequencer: remove the broken GIT_QUIET handling
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>
2020-02-16 15:40:42 -08:00
Elijah Newren
e98c4269c8 rebase (interactive-backend): fix handling of commits that become empty
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>
2020-02-16 15:40:42 -08:00
Elijah Newren
d48e5e21da rebase (interactive-backend): make --keep-empty the default
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>
2020-02-16 15:40:42 -08:00
Elijah Newren
22a69fda19 git-rebase.txt: update description of --allow-empty-message
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>
2020-01-17 13:58:30 -08:00
Junio C Hamano
4d924528d8 Revert "Merge branch 'ra/rebase-i-more-options'"
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>
2020-01-12 13:25:18 -08:00
Junio C Hamano
e0e1ac5db0 Merge branch 'en/rebase-signoff-fix'
"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
2020-01-02 12:38:30 -08:00
Elijah Newren
4fe7e43c53 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>
2019-12-20 11:29:49 -08:00
Junio C Hamano
71a7de7a99 Merge branch 'dl/rebase-with-autobase'
"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
2019-12-16 13:08:32 -08:00
Junio C Hamano
37c2619d91 Merge branch 'ag/sequencer-todo-updates'
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
2019-12-16 13:08:31 -08:00
Junio C Hamano
5d9324e0f4 Merge branch 'ra/rebase-i-more-options'
"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
2019-12-10 13:11:41 -08:00
Denton Liu
cae0bc09ab rebase: fix format.useAutoBase breakage
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>
2019-12-05 06:06:18 -08:00
Junio C Hamano
d82dfa7f5b rebase -i: finishing touches to --reset-author-date
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>
2019-11-25 15:09:29 +09:00
Alban Gruin
a2dd67f105 rebase: fill `squash_onto' in get_replay_opts()
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>
2019-11-25 12:24:49 +09:00
Junio C Hamano
0c51181ffb Merge branch 'js/rebase-deprecate-preserve-merges'
"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
2019-11-10 18:02:13 +09:00
Rohit Ashiwal
fe28ad8520 rebase: add --reset-author-date
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>
2019-11-02 15:37:12 +09:00
Rohit Ashiwal
08187b4cba rebase -i: support --ignore-date
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>
2019-11-02 15:37:12 +09:00
Rohit Ashiwal
cbd8db17ac rebase -i: support --committer-date-is-author-date
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>
2019-11-02 15:36:23 +09:00
Rohit Ashiwal
ba51d2fb24 rebase -i: add --ignore-whitespace flag
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>
2019-11-02 15:34:50 +09:00
Denton Liu
feebd2d256 rebase: hide --preserve-merges option
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>
2019-10-21 12:03:49 +09:00
Junio C Hamano
974bdb0205 Merge branch 'bw/rebase-autostash-keep-current-branch'
"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
2019-09-30 13:19:32 +09:00
Junio C Hamano
640f9cd599 Merge branch 'dl/rebase-i-keep-base'
"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
2019-09-30 13:19:31 +09:00
Junio C Hamano
917a319ea5 Merge branch 'js/rebase-r-strategy'
"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
2019-09-18 11:50:07 -07:00
Ben Wijen
bf1e28e0ad builtin/rebase.c: Remove pointless message
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>
2019-09-07 10:17:05 -07:00
Ben Wijen
d2172ef02d builtin/rebase.c: make sure the active branch isn't moved when autostashing
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>
2019-09-07 10:17:05 -07:00
Denton Liu
414d924beb rebase: teach rebase --keep-base
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>
2019-08-27 15:33:40 -07:00
Denton Liu
4effc5bc96 rebase: fast-forward --fork-point in more cases
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>
2019-08-27 15:33:40 -07:00
Denton Liu
c0efb4c1dd rebase: fast-forward --onto in more cases
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>
2019-08-27 15:33:40 -07:00
Denton Liu
2b318aa6c3 rebase: refactor can_fast_forward into goto tower
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>
2019-08-27 15:33:40 -07:00
Johannes Schindelin
e1fac531ea rebase -r: do not (re-)generate root commits with --root *and* --onto
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>
2019-07-31 12:24:07 -07:00
Johannes Schindelin
e145d99347 rebase -r: support merge strategies other than recursive
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>
2019-07-31 12:24:07 -07:00
Johannes Schindelin
5efed0ecf9 rebase: fold git-rebase--common into the -p backend
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>
2019-07-31 12:24:06 -07:00
Johannes Schindelin
d5b581f228 Drop unused git-rebase--am.sh
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>
2019-07-31 12:24:06 -07:00
Junio C Hamano
38dac334d7 Merge branch 'js/rebase-cleanup'
A few leftover cleanup to "git rebase" in C.

* js/rebase-cleanup:
  git: mark cmd_rebase as requiring a worktree
  rebase: fix white-space
2019-07-29 12:39:14 -07:00
Junio C Hamano
dea6737bb7 Merge branch 'ds/close-object-store' into maint
The commit-graph file is now part of the "files that the runtime
may keep open file descriptors on, all of which would need to be
closed when done with the object store", and the file descriptor to
an existing commit-graph file now is closed before "gc" finalizes a
new instance to replace it.

* ds/close-object-store:
  packfile: rename close_all_packs to close_object_store
  packfile: close commit-graph in close_all_packs
  commit-graph: use raw_object_store when closing
  commit-graph: extract write_commit_graph_file()
  commit-graph: extract copy_oids_to_commits()
  commit-graph: extract count_distinct_commits()
  commit-graph: extract fill_oids_from_all_packs()
  commit-graph: extract fill_oids_from_commit_hex()
  commit-graph: extract fill_oids_from_packs()
  commit-graph: create write_commit_graph_context
  commit-graph: remove Future Work section
  commit-graph: collapse parameters into flags
  commit-graph: return with errors during write
  commit-graph: fix the_repository reference
2019-07-29 12:38:22 -07:00
Junio C Hamano
649cae69bc Merge branch 'pw/rebase-abort-clean-rewritten' into maint
"git rebase --abort" used to leave refs/rewritten/ when concluding
"git rebase -r", which has been corrected.

* pw/rebase-abort-clean-rewritten:
  rebase --abort/--quit: cleanup refs/rewritten
  sequencer: return errors from sequencer_remove_state()
  rebase: warn if state directory cannot be removed
  rebase: fix a memory leak
2019-07-29 12:38:20 -07:00
Junio C Hamano
8eb5097bea Merge branch 'js/rebase-reschedule-applies-only-to-interactive' into maint
The configuration variable rebase.rescheduleFailedExec should be
effective only while running an interactive rebase and should not
affect anything when running an non-interactive one, which was not
the case.  This has been corrected.

* js/rebase-reschedule-applies-only-to-interactive:
  rebase --am: ignore rebase.rescheduleFailedExec
2019-07-29 12:38:18 -07:00
Johannes Schindelin
80dfc9242e git: mark cmd_rebase as requiring a worktree
We skipped marking the "rebase" built-in as requiring a .git/ directory
and a worktree only to allow to spawn the scripted version of `git
rebase`.

Now that we no longer have that escape hatch, we can change that to the
canonical form.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-07-25 08:58:13 -07:00
Johannes Schindelin
cbea646153 rebase: fix white-space
This trailing space was inadvertently introduced in 9fbcc3d203 (Merge
branch 'js/rebase-orig-head-fix', 2019-03-20).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-07-25 08:58:03 -07:00
Junio C Hamano
1eb0a12ec3 Merge branch 'nd/tree-walk-with-repo'
The tree-walk API learned to pass an in-core repository
instance throughout more codepaths.

* nd/tree-walk-with-repo:
  t7814: do not generate same commits in different repos
  Use the right 'struct repository' instead of the_repository
  match-trees.c: remove the_repo from shift_tree*()
  tree-walk.c: remove the_repo from get_tree_entry_follow_symlinks()
  tree-walk.c: remove the_repo from get_tree_entry()
  tree-walk.c: remove the_repo from fill_tree_descriptor()
  sha1-file.c: remove the_repo from read_object_with_reference()
2019-07-19 11:30:21 -07:00
Junio C Hamano
64096fb41d Merge branch 'js/rebase-reschedule-applies-only-to-interactive'
The configuration variable rebase.rescheduleFailedExec should be
effective only while running an interactive rebase and should not
affect anything when running an non-interactive one, which was not
the case.  This has been corrected.

* js/rebase-reschedule-applies-only-to-interactive:
  rebase --am: ignore rebase.rescheduleFailedExec
2019-07-11 15:16:48 -07:00
Junio C Hamano
f496b064fc Merge branch 'nd/switch-and-restore'
Two new commands "git switch" and "git restore" are introduced to
split "checking out a branch to work on advancing its history" and
"checking out paths out of the index and/or a tree-ish to work on
advancing the current history" out of the single "git checkout"
command.

* nd/switch-and-restore: (46 commits)
  completion: disable dwim on "git switch -d"
  switch: allow to switch in the middle of bisect
  t2027: use test_must_be_empty
  Declare both git-switch and git-restore experimental
  help: move git-diff and git-reset to different groups
  doc: promote "git restore"
  user-manual.txt: prefer 'merge --abort' over 'reset --hard'
  completion: support restore
  t: add tests for restore
  restore: support --patch
  restore: replace --force with --ignore-unmerged
  restore: default to --source=HEAD when only --staged is specified
  restore: reject invalid combinations with --staged
  restore: add --worktree and --staged
  checkout: factor out worktree checkout code
  restore: disable overlay mode by default
  restore: make pathspec mandatory
  restore: take tree-ish from --source option instead
  checkout: split part of it to new command 'restore'
  doc: promote "git switch"
  ...
2019-07-09 15:25:44 -07:00
Junio C Hamano
88f95e49af Merge branch 'pw/rebase-abort-clean-rewritten'
"git rebase --abort" used to leave refs/rewritten/ when concluding
"git rebase -r", which has been corrected.

* pw/rebase-abort-clean-rewritten:
  rebase --abort/--quit: cleanup refs/rewritten
  sequencer: return errors from sequencer_remove_state()
  rebase: warn if state directory cannot be removed
  rebase: fix a memory leak
2019-07-09 15:25:41 -07:00