"rebase -i" segfaulted when rearranging a sequence that has a
fix-up that applies another fix-up (which may or may not be a
fix-up of yet another step).
* js/rebase-autosquash-double-fixup-fix:
rebase --autosquash: fix a potential segfault
When rearranging the todo list so that the fixups/squashes are reordered
just after the commits they intend to fix up, we use two arrays to
maintain that list: `next` and `tail`.
The idea is that `next[i]`, if set to a non-negative value, contains the
index of the item that should be rearranged just after the `i`th item.
To avoid having to walk the entire `next` chain when appending another
fixup/squash, we also store the end of the `next` chain in `tail[i]`.
The logic we currently use to update these array items is based on the
assumption that given a fixup/squash item at index `i`, we just found
the index `i2` indicating the first item in that fixup chain.
However, as reported by Paul Ganssle, that need not be true: the special
form `fixup! <commit-hash>` is allowed to point to _another_ fixup
commit in the middle of the fixup chain.
Example:
* 0192a To fixup
* 02f12 fixup! To fixup
* 03763 fixup! To fixup
* 04ecb fixup! 02f12
Note how the fourth commit targets the second commit, which is already a
fixup that targets the first commit.
Previously, we would update `next` and `tail` under our assumption that
every `fixup!` commit would find the start of the `fixup!`/`squash!`
chain. This would lead to a segmentation fault because we would actually
end up with a `next[i]` pointing to a `fixup!` but the corresponding
`tail[i]` pointing nowhere, which would the lead to a segmentation
fault.
Let's fix this by _inserting_, rather than _appending_, the item. In
other words, if we make a given line successor of another line, we do
not simply forget any previously set successor of the latter, but make
it a successor of the former.
In the above example, at the point when we insert 04ecb just after
02f12, 03763 would already be recorded as a successor of 04ecb, and we
now "squeeze in" 04ecb.
To complete the idea, we now no longer assume that `next[i]` pointing to
a line means that `last[i]` points to a line, too. Instead, we extend
the concept of `last` to cover also partial `fixup!`/`squash!` chains,
i.e. chains starting in the middle of a larger such chain.
In the above example, after processing all lines, `last[0]`
(corresponding to 0192a) would point to 03763, which indeed is the end
of the overall `fixup!` chain, and `last[1]` (corresponding to 02f12)
would point to 04ecb (which is the last `fixup!` targeting 02f12, but it
has 03763 as successor, i.e. it is not the end of overall `fixup!`
chain).
Reported-by: Paul Ganssle <paul@ganssle.io>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
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
"git rebase" learned the "--no-gpg-sign" option to countermand
commit.gpgSign the user may have.
* dd/no-gpg-sign:
Documentation: document merge option --no-gpg-sign
Documentation: merge commit-tree --[no-]gpg-sign
Documentation: reword commit --no-gpg-sign
Documentation: document am --no-gpg-sign
cherry-pick/revert: honour --no-gpg-sign in all case
rebase.c: honour --no-gpg-sign
"git rebase" with the merge backend did not work well when the
rebase.abbreviateCommands configuration was set.
* ag/rebase-merge-allow-ff-under-abbrev-command:
t3432: test `--merge' with `rebase.abbreviateCommands = true', too
sequencer: don't abbreviate a command if it doesn't have a short form
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>
While many users who intentionally create empty commits do not want them
thrown away by a rebase, there are third-party tools that generate empty
commits that a user might not want. In the past, users have used rebase
to get rid of such commits (a side-effect of the fact that the --apply
backend is not currently capable of keeping them). While such users
could fire up an interactive rebase and just remove the lines
corresponding to empty commits, that might be difficult if the
third-party tool generates many of them. Simplify this task for users
by marking such lines with a suffix of " # empty" in the todo list.
Suggested-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>
Explicitly remove autostash file in apply_autostash() once it has been
applied successfully.
This is currently a no-op because the only users of this function will unlink
the state (including the autostash file) after this function runs.
However, in the future, we will introduce a user of the function that
does not explicitly remove the state so we do it here.
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 preferred terminology is to refer to object identifiers as "OIDs".
Rename the `stash_sha1` variable to `stash_oid` in order to conform to
this.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In order to make apply_autostash() more generic for future extraction, make
it accept a `path` argument so that the location from where to read the
reference to the autostash commit can be customized. Remove the `opts`
argument since it was unused before anyway.
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>
In the future, we plan on externing read_oneliner(). Future users of
read_oneliner() will want the ability to output warnings in the event
that the `path` doesn't exist. Introduce the
`READ_ONELINER_WARN_MISSING` flag which, if active, would issue a
warning when a file doesn't exist by always executing warning_errno()
in the case where strbuf_read_file() fails.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In a future commit, we will need read_oneliner() to accept flags other
than just `skip_if_empty`. Instead of having an argument for each flag,
teach read_oneliner() to accept the bitfield `flags` instead. For now,
only recognize the `READ_ONELINER_SKIP_IF_EMPTY` flag. More flags will
be added in a future commit.
The result of this is that parallel topics which introduce invocations
of read_oneliner() will still be compatible with this new function
signature since, instead of passing 1 or 0 for `skip_if_empty`, they'll
be passing 1 or 0 to `flags`, which gives equivalent behavior.
Mechanically fix up invocations of read_oneliner() with the following
spatch
@@
expression a, b;
@@
read_oneliner(a, b,
- 1
+ READ_ONELINER_SKIP_IF_EMPTY
)
and manually break up long lines in the result.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We currently check whether a file exists and return early before reading
the file. Instead of accessing the file twice, always read the file and
check `errno` to see if the file doesn't exist.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There is a lot of code to honor GIT_REFLOG_ACTION throughout git,
including some in sequencer.c; unfortunately, reflog_message() and its
callers ignored it. Instruct reflog_message() to check the existing
environment variable, and use it when present as an override to
action_name().
Also restructure pick_commits() to only temporarily modify
GIT_REFLOG_ACTION for a short duration and then restore the old value,
so that when we do this setting within a loop we do not keep adding "
(pick)" substrings and end up with a reflog message of the form
rebase (pick) (pick) (pick) (finish): returning to refs/heads/master
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In read_populate_opts(), we call read_oneliner() _after_ calling
strbuf_release(). This means that `buf` is leaked at the end of the
function.
Always clean up the strbuf by going to `done_rebase_i` whether or not
we return an error.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
{cherry-pick,revert} --edit hasn't honoured --no-gpg-sign yet.
Pass this option down to git-commit to honour it.
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When the sequencer is requested to abbreviate commands, it will replace
those that do not have a short form (eg. `noop') by a comment mark.
`noop' serves no purpose, except when fast-forwarding (ie. by running
`git rebase'). Removing it will break this command when
`rebase.abbreviateCommands' is set to true.
Teach todo_list_to_strbuf() to check if a command has an actual
short form, and to ignore it if not.
Signed-off-by: Alban Gruin <alban.gruin@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Provide more information (e.g. the object of the tree-ish in which
the blob being converted appears, in addition to its path, which
has already been given) to smudge/clean conversion filters.
* bc/filter-process:
t0021: test filter metadata for additional cases
builtin/reset: compute checkout metadata for reset
builtin/rebase: compute checkout metadata for rebases
builtin/clone: compute checkout metadata for clones
builtin/checkout: compute checkout metadata for checkouts
convert: provide additional metadata to filters
convert: permit passing additional metadata to filter processes
builtin/checkout: pass branch info down to checkout_worktree
SHA-256 transition continues.
* bc/sha-256-part-1-of-4: (22 commits)
fast-import: add options for rewriting submodules
fast-import: add a generic function to iterate over marks
fast-import: make find_marks work on any mark set
fast-import: add helper function for inserting mark object entries
fast-import: permit reading multiple marks files
commit: use expected signature header for SHA-256
worktree: allow repository version 1
init-db: move writing repo version into a function
builtin/init-db: add environment variable for new repo hash
builtin/init-db: allow specifying hash algorithm on command line
setup: allow check_repository_format to read repository format
t/helper: make repository tests hash independent
t/helper: initialize repository if necessary
t/helper/test-dump-split-index: initialize git repository
t6300: make hash algorithm independent
t6300: abstract away SHA-1-specific constants
t: use hash-specific lookup tables to define test constants
repository: require a build flag to use SHA-256
hex: add functions to parse hex object IDs in any algorithm
hex: introduce parsing variants taking hash algorithms
...
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
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
In commit e98c4269c8 ("rebase (interactive-backend): fix handling of
commits that become empty", 2020-02-15), the merge backend was changed
to drop commits that did not start empty but became so after being
applied (because their changes were a subset of what was already
upstream). This new code path did not need to go through the process of
creating a commit, since we were dropping the commit instead.
Unfortunately, this also means we bypassed the clearing of the
CHERRY_PICK_HEAD and MERGE_MSG files, which if there were no further
commits to cherry-pick would mean that the rebase would end but assume
there was still an operation in progress. Ensure that we clear such
state files when we decide to drop the commit.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"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
The transition plan anticipates that we will allow signatures using
multiple algorithms in a single commit. In order to do so, we need to
use a different header per algorithm so that it will be obvious over
which data to compute the signature.
The transition plan specifies that we should use "gpgsig-sha256", so
wire up the commit code such that it can write and parse the current
algorithm, and it can remove the headers for any algorithm when creating
a new commit. Add tests to ensure that we write using the right header
and that git fsck doesn't reject these commits.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
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>
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>
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
"git rebase -i" identifies existing commits in its todo file with
their abbreviated object name, which could become ambigous as it
goes to create new commits, and has a mechanism to avoid ambiguity
in the main part of its execution. A few other cases however were
not covered by the protection against ambiguity, which has been
corrected.
* js/rebase-i-with-colliding-hash:
rebase -i: also avoid SHA-1 collisions with missingCommitsCheck
rebase -i: re-fix short SHA-1 collision
parse_insn_line(): improve error message when parsing failed
The Undefined Behavior Sanitizer in clang-11 seems to have learned a new
trick: it complains about computing offsets from a NULL pointer, even if
that offset is 0. This causes numerous test failures. For example, from
t1090:
unpack-trees.c:1355:41: runtime error: applying zero offset to null pointer
...
not ok 6 - in partial clone, sparse checkout only fetches needed blobs
The code in question looks like this:
struct cache_entry **cache_end = cache + nr;
...
while (cache != cache_end)
and we sometimes pass in a NULL and 0 for "cache" and "nr". This is
conceptually fine, as "cache_end" would be equal to "cache" in this
case, and we wouldn't enter the loop at all. But computing even a zero
offset violates the C standard. And given the fact that UBSan is
noticing this behavior, this might be a potential problem spot if the
compiler starts making unexpected assumptions based on undefined
behavior.
So let's just avoid it, which is pretty easy. In some cases we can just
switch to iterating with a numeric index (as we do in sequencer.c here).
In other cases (like the cache_end one) the use of an end pointer is
more natural; we can keep that by just explicitly checking for the
NULL/0 case when assigning the end pointer.
Note that there are two ways you can write this latter case, checking
for the pointer:
cache_end = cache ? cache + nr : cache;
or the size:
cache_end = nr ? cache + nr : cache;
For the case of a NULL/0 ptr/len combo, they are equivalent. But writing
it the second way (as this patch does) has the property that if somebody
were to incorrectly pass a NULL pointer with a non-zero length, we'd
continue to notice and segfault, rather than silently pretending the
length was zero.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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>
In 66ae9a57b8 (t3404: rebase -i: demonstrate short SHA-1 collision,
2013-08-23), we added a test case that demonstrated how it is possible
that a previously unambiguous short commit ID could become ambiguous
*during* a rebase.
In 75c6976655 (rebase -i: fix short SHA-1 collision, 2013-08-23), we
fixed that problem simply by writing out the todo list with expanded
commit IDs (except *right* before letting the user edit the todo list,
in which case we shorten them, but we expand them right after the file
was edited).
However, the bug resurfaced as a side effect of 393adf7a6f (sequencer:
directly call pick_commits() from complete_action(), 2019-11-24): as of
this commit, the sequencer no longer re-reads the todo list after
writing it out with expanded commit IDs.
The only redeeming factor is that the todo list is already parsed at
that stage, including all the commits corresponding to the commands,
therefore the sequencer can continue even if the internal todo list has
short commit IDs.
That does not prevent problems, though: the sequencer writes out the
`done` and `git-rebase-todo` files incrementally (i.e. overwriting the
todo list with a version that has _short_ commit IDs), and if a merge
conflict happens, or if an `edit` or a `break` command is encountered, a
subsequent `git rebase --continue` _will_ re-read the todo list, opening
an opportunity for the "short SHA-1 collision" bug again.
To avoid that, let's make sure that we do expand the commit IDs in the
todo list as soon as we have parsed it after letting the user edit it.
Additionally, we improve the 'short SHA-1 collide' test case in t3404 to
test specifically for the case where the rebase is resumed. We also
hard-code the expected colliding short SHA-1s, to document the
expectation (and to make it easier on future readers).
Note that we specifically test that the short commit ID is used in the
`git-rebase-todo.tmp` file: this file is created by the fake editor in
the test script and reflects the state that would have been presented to
the user to edit.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the case that a `get_oid()` call failed, we showed some rather bogus
part of the line instead of the precise string we sent to said function.
That makes it rather hard for users to understand what is going wrong,
so let's fix that.
While at it, return a negative value from `parse_insn_line()` in case of
an error, as per our convention. This function's only caller,
`todo_list_parse_insn_buffer()`, cares only whether that return value is
non-zero or not, i.e. does not need to be changed.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
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>
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
