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Ævar Arnfjörð Bjarmason a8cc594333 hooks: fix an obscure TOCTOU "did we just run a hook?" race
Fix a Time-of-check to time-of-use (TOCTOU) race in code added in
680ee550d7 (commit: skip discarding the index if there is no
pre-commit hook, 2017-08-14).

This obscure race condition can occur if we e.g. ran the "pre-commit"
hook and it modified the index, but hook_exists() returns false later
on (e.g., because the hook itself went away, the directory became
unreadable, etc.). Then we won't call discard_cache() when we should
have.

The race condition itself probably doesn't matter, and users would
have been unlikely to run into it in practice. This problem has been
noted on-list when 680ee550d7 was discussed[1], but had not been
fixed.

This change is mainly intended to improve the readability of the code
involved, and to make reasoning about it more straightforward. It
wasn't as obvious what we were trying to do here, but by having an
"invoked_hook" it's clearer that e.g. our discard_cache() is happening
because of the earlier hook execution.

Let's also change this for the push-to-checkout hook. Now instead of
checking if the hook exists and either doing a push to checkout or a
push to deploy we'll always attempt a push to checkout. If the hook
doesn't exist we'll fall back on push to deploy. The same behavior as
before, without the TOCTOU race. See 0855331941 (receive-pack:
support push-to-checkout hook, 2014-12-01) for the introduction of the
previous behavior.

This leaves uses of hook_exists() in two places that matter. The
"reference-transaction" check in refs.c, see 6754159767 (refs:
implement reference transaction hook, 2020-06-19), and the
"prepare-commit-msg" hook, see 66618a50f9 (sequencer: run
'prepare-commit-msg' hook, 2018-01-24).

In both of those cases we're saving ourselves CPU time by not
preparing data for the hook that we'll then do nothing with if we
don't have the hook. So using this "invoked_hook" pattern doesn't make
sense in those cases.

The "reference-transaction" and "prepare-commit-msg" hook also aren't
racy. In those cases we'll skip the hook runs if we race with a new
hook being added, whereas in the TOCTOU races being fixed here we were
incorrectly skipping the required post-hook logic.

1. https://lore.kernel.org/git/20170810191613.kpmhzg4seyxy3cpq@sigill.intra.peff.net/

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-07 13:00:53 -08:00
Ævar Arnfjörð Bjarmason 9f6e63b966 merge: don't run post-hook logic on --no-verify
Fix a minor bug introduced in bc40ce4de6 (merge: --no-verify to
bypass pre-merge-commit hook, 2019-08-07), when that change made the
--no-verify option bypass the "pre-merge-commit" hook it didn't update
the corresponding find_hook() (later hook_exists()) condition.

As can be seen in the preceding commit in 6098817fd7 (git-merge:
honor pre-merge-commit hook, 2019-08-07) the two should go hand in
hand. There's no point in invoking discard_cache() here if the hook
couldn't have possibly updated the index.

It's buggy that we use "hook_exist()" here, and as discussed in the
subsequent commit it's subject to obscure race conditions that we're
about to fix, but for now this change is a strict improvement that
retains any caveats to do with the use of "hooks_exist()" as-is.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-07 13:00:52 -08:00
Junio C Hamano bcd020f88e Merge branch 'pw/use-in-process-checkout-in-rebase'
Use an internal call to reset_head() helper function instead of
spawning "git checkout" in "rebase", and update code paths that are
involved in the change.

* pw/use-in-process-checkout-in-rebase:
  rebase -m: don't fork git checkout
  rebase --apply: set ORIG_HEAD correctly
  rebase --apply: fix reflog
  reset_head(): take struct rebase_head_opts
  rebase: cleanup reset_head() calls
  create_autostash(): remove unneeded parameter
  reset_head(): make default_reflog_action optional
  reset_head(): factor out ref updates
  reset_head(): remove action parameter
  rebase --apply: don't run post-checkout hook if there is an error
  rebase: do not remove untracked files on checkout
  rebase: pass correct arguments to post-checkout hook
  t5403: refactor rebase post-checkout hook tests
  rebase: factor out checkout for up to date branch
2022-02-18 13:53:27 -08:00
Junio C Hamano c70b5e7187 Merge branch 'en/plug-leaks-in-merge'
Leakfix.

* en/plug-leaks-in-merge:
  merge: fix memory leaks in cmd_merge()
  merge-ort: fix memory leak in merge_ort_internal()
2022-02-09 14:21:00 -08:00
Junio C Hamano c70bc338e9 Merge branch 'ab/config-based-hooks-2'
More "config-based hooks".

* ab/config-based-hooks-2:
  run-command: remove old run_hook_{le,ve}() hook API
  receive-pack: convert push-to-checkout hook to hook.h
  read-cache: convert post-index-change to use hook.h
  commit: convert {pre-commit,prepare-commit-msg} hook to hook.h
  git-p4: use 'git hook' to run hooks
  send-email: use 'git hook run' for 'sendemail-validate'
  git hook run: add an --ignore-missing flag
  hooks: convert worktree 'post-checkout' hook to hook library
  hooks: convert non-worktree 'post-checkout' hook to hook library
  merge: convert post-merge to use hook.h
  am: convert applypatch-msg to use hook.h
  rebase: convert pre-rebase to use hook.h
  hook API: add a run_hooks_l() wrapper
  am: convert {pre,post}-applypatch to use hook.h
  gc: use hook library for pre-auto-gc hook
  hook API: add a run_hooks() wrapper
  hook: add 'run' subcommand
2022-02-09 14:21:00 -08:00
Phillip Wood b7de153bd9 create_autostash(): remove unneeded parameter
The default_reflog parameter of create_autostash() is passed to
reset_head(). However as creating a stash does not involve updating
any refs the parameter is not used by reset_head(). Removing the
parameter from create_autostash() simplifies the callers.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-26 12:08:53 -08:00
Elijah Newren 6046f7a91c merge: fix memory leaks in cmd_merge()
There were two commit_lists created in cmd_merge() that were only
conditionally free()'d.  Add a quick conditional call to
free_commit_list() for each of them at the end of the function.

Testing this commit against t6404 under valgrind shows that this patch
fixes the following two leaks:

    16 bytes in 1 blocks are definitely lost in loss record 16 of 126
       at 0x484086F: malloc (vg_replace_malloc.c:380)
       by 0x69FFEB: do_xmalloc (wrapper.c:41)
       by 0x6A0073: xmalloc (wrapper.c:62)
       by 0x52A72D: commit_list_insert (commit.c:556)
       by 0x47FC93: reduce_parents (merge.c:1114)
       by 0x4801EE: collect_parents (merge.c:1214)
       by 0x480B56: cmd_merge (merge.c:1465)
       by 0x40686E: run_builtin (git.c:464)
       by 0x406C51: handle_builtin (git.c:716)
       by 0x406E96: run_argv (git.c:783)
       by 0x40730A: cmd_main (git.c:914)
       by 0x4E7DFA: main (common-main.c:56)

    8 (16 direct, 32 indirect) bytes in 1 blocks are definitely lost in \
    loss record 61 of 126
       at 0x484086F: malloc (vg_replace_malloc.c:380)
       by 0x69FFEB: do_xmalloc (wrapper.c:41)
       by 0x6A0073: xmalloc (wrapper.c:62)
       by 0x52A72D: commit_list_insert (commit.c:556)
       by 0x52A8F2: commit_list_insert_by_date (commit.c:620)
       by 0x5270AC: get_merge_bases_many_0 (commit-reach.c:413)
       by 0x52716C: repo_get_merge_bases (commit-reach.c:438)
       by 0x480E5A: cmd_merge (merge.c:1520)
       by 0x40686E: run_builtin (git.c:464)
       by 0x406C51: handle_builtin (git.c:716)
       by 0x406E96: run_argv (git.c:783)
       by 0x40730A: cmd_main (git.c:914)

There are still 3 leaks in chdir_notify_register() after this, but
chdir_notify_register() has been brought up on the list before and folks
were not a fan of fixing those, so I'm not touching them.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-21 15:50:47 -08:00
Junio C Hamano c17de5a505 Merge branch 'ja/i18n-similar-messages'
Similar message templates have been consolidated so that
translators need to work on fewer number of messages.

* ja/i18n-similar-messages:
  i18n: turn even more messages into "cannot be used together" ones
  i18n: ref-filter: factorize "%(foo) atom used without %(bar) atom"
  i18n: factorize "--foo outside a repository"
  i18n: refactor "unrecognized %(foo) argument" strings
  i18n: factorize "no directory given for --foo"
  i18n: factorize "--foo requires --bar" and the like
  i18n: tag.c factorize i18n strings
  i18n: standardize "cannot open" and "cannot read"
  i18n: turn "options are incompatible" into "cannot be used together"
  i18n: refactor "%s, %s and %s are mutually exclusive"
  i18n: refactor "foo and bar are mutually exclusive"
2022-01-10 11:52:56 -08:00
Emily Shaffer 67ad630617 merge: convert post-merge to use hook.h
Teach post-merge to use the hook.h library instead of the
run-command.h library to run hooks.

Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Emily Shaffer <emilyshaffer@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-07 15:19:34 -08:00
Junio C Hamano bb14cfdfd7 Merge branch 'jc/merge-detached-head-name'
The default merge message prepared by "git merge" records the name
of the current branch; the name can be overridden with a new option
to allow users to pretend a merge is made on a different branch.

* jc/merge-detached-head-name:
  merge: allow to pretend a merge is made into a different branch
2022-01-05 14:01:30 -08:00
Jean-Noël Avila 12909b6b8a i18n: turn "options are incompatible" into "cannot be used together"
Signed-off-by: Jean-Noël Avila <jn.avila@free.fr>
Reviewed-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-05 13:29:23 -08:00
Junio C Hamano bd2bc94252 merge: allow to pretend a merge is made into a different branch
When a series of patches for a topic-B depends on having topic-A,
the workflow to prepare the topic-B branch would look like this:

    $ git checkout -b topic-B main
    $ git merge --no-ff --no-edit topic-A
    $ git am <mbox-for-topic-B

When topic-A gets updated, recreating the first merge and rebasing
the rest of the topic-B, all on detached HEAD, is a useful
technique.  After updating topic-A with its new round of patches:

    $ git checkout topic-B
    $ prev=$(git rev-parse 'HEAD^{/^Merge branch .topic-A. into}')
    $ git checkout --detach $prev^1
    $ git merge --no-ff --no-edit topic-A
    $ git rebase --onto HEAD $prev @{-1}^0
    $ git checkout -B @{-1}

This will

 (0) check out the current topic-B.
 (1) find the previous merge of topic-A into topic-B.
 (2) detach the HEAD to the parent of the previous merge.
 (3) merge the updated topic-A to it.
 (4) reapply the patches to rebuild the rest of topic-B.
 (5) update topic-B with the result.

without contaminating the reflog of topic-B too much.  topic-B@{1}
is the "logically previous" state before topic-A got updated, for
example.  At (4), comparison (e.g. range-diff) between HEAD and
@{-1} is a meaningful way to sanity check the result, and the same
can be done at (5) by comparing topic-B and topic-B@{1}.

But there is one glitch.  The merge into the detached HEAD done in
the step (3) above gives us "Merge branch 'topic-A' into HEAD", and
does not say "into topic-B".

Teach the "--into-name=<branch>" option to "git merge" and its
underlying "git fmt-merge-message", to pretend as if we were merging
into <branch>, no matter what branch we are actually merging into,
when they prepare the merge message.  The pretend name honors the
usual "into <target>" suppression mechanism, which can be seen in
the tests added here.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-20 14:55:02 -08:00
Ævar Arnfjörð Bjarmason 2b7098936c run-command API users: use strvec_pushl(), not argv construction
Change a pattern of hardcoding an "argv" array size, populating it and
assigning to the "argv" member of "struct child_process" to instead
use "strvec_pushl()" to add data to the "args" member.

This implements the same behavior as before in fewer lines of code,
and moves us further towards being able to remove the "argv" member in
a subsequent commit.

Since we've entirely removed the "argv" variable(s) we can be sure
that no potential logic errors of the type discussed in a preceding
commit are being introduced here, i.e. ones where the local "argv" was
being modified after the assignment to "struct child_process"'s
"argv".

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-11-25 22:15:07 -08:00
Junio C Hamano 54c4f8ce52 Merge branch 'ab/mark-leak-free-tests-more'
Bunch of tests are marked as "passing leak check".

* ab/mark-leak-free-tests-more:
  merge: add missing strbuf_release()
  ls-files: add missing string_list_clear()
  ls-files: fix a trivial dir_clear() leak
  tests: fix test-oid-array leak, test in SANITIZE=leak
  tests: fix a memory leak in test-oidtree.c
  tests: fix a memory leak in test-parse-options.c
  tests: fix a memory leak in test-prio-queue.c
2021-10-25 16:06:59 -07:00
Junio C Hamano a5e61a4225 Merge branch 'ab/config-based-hooks-1'
Mostly preliminary clean-up in the hook API.

* ab/config-based-hooks-1:
  hook-list.h: add a generated list of hooks, like config-list.h
  hook.c users: use "hook_exists()" instead of "find_hook()"
  hook.c: add a hook_exists() wrapper and use it in bugreport.c
  hook.[ch]: move find_hook() from run-command.c to hook.c
  Makefile: remove an out-of-date comment
  Makefile: don't perform "mv $@+ $@" dance for $(GENERATED_H)
  Makefile: stop hardcoding {command,config}-list.h
  Makefile: mark "check" target as .PHONY
2021-10-13 15:15:57 -07:00
Junio C Hamano a7c2daa06d Merge branch 'en/removing-untracked-fixes'
Various fixes in code paths that move untracked files away to make room.

* en/removing-untracked-fixes:
  Documentation: call out commands that nuke untracked files/directories
  Comment important codepaths regarding nuking untracked files/dirs
  unpack-trees: avoid nuking untracked dir in way of locally deleted file
  unpack-trees: avoid nuking untracked dir in way of unmerged file
  Change unpack_trees' 'reset' flag into an enum
  Remove ignored files by default when they are in the way
  unpack-trees: make dir an internal-only struct
  unpack-trees: introduce preserve_ignored to unpack_trees_options
  read-tree, merge-recursive: overwrite ignored files by default
  checkout, read-tree: fix leak of unpack_trees_options.dir
  t2500: add various tests for nuking untracked files
2021-10-13 15:15:57 -07:00
Ævar Arnfjörð Bjarmason 465028e0e2 merge: add missing strbuf_release()
We strbuf_reset() this "struct strbuf" in a loop earlier, but never
freed it. Plugs a memory leak that's been here ever since this code
got introduced in 1c7b76be7d (Build in merge, 2008-07-07).

This takes us from 68 failed tests in "t7600-merge.sh" to 59 under
SANITIZE=leak, and makes "t7604-merge-custom-message.sh" pass!

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-07 15:40:16 -07:00
Elijah Newren 1b5f37334a Remove ignored files by default when they are in the way
Change several commands to remove ignored files by default when they are
in the way.  Since some commands (checkout, merge) take a
--no-overwrite-ignore option to allow the user to configure this, and it
may make sense to add that option to more commands (and in the case of
merge, actually plumb that configuration option through to more of the
backends than just the fast-forwarding special case), add little
comments about where such flags would be used.

Incidentally, this fixes a test failure in t7112.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-27 13:38:37 -07:00
Elijah Newren 04988c8d18 unpack-trees: introduce preserve_ignored to unpack_trees_options
Currently, every caller of unpack_trees() that wants to ensure ignored
files are overwritten by default needs to:
   * allocate unpack_trees_options.dir
   * flip the DIR_SHOW_IGNORED flag in unpack_trees_options.dir->flags
   * call setup_standard_excludes
AND then after the call to unpack_trees() needs to
   * call dir_clear()
   * deallocate unpack_trees_options.dir
That's a fair amount of boilerplate, and every caller uses identical
code.  Make this easier by instead introducing a new boolean value where
the default value (0) does what we want so that new callers of
unpack_trees() automatically get the appropriate behavior.  And move all
the handling of unpack_trees_options.dir into unpack_trees() itself.

While preserve_ignored = 0 is the behavior we feel is the appropriate
default, we defer fixing commands to use the appropriate default until a
later commit.  So, this commit introduces several locations where we
manually set preserve_ignored=1.  This makes it clear where code paths
were previously preserving ignored files when they should not have been;
a future commit will flip these to instead use a value of 0 to get the
behavior we want.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-27 13:38:37 -07:00
Ævar Arnfjörð Bjarmason 07a348e746 hook.c users: use "hook_exists()" instead of "find_hook()"
Use the new hook_exists() function instead of find_hook() where the
latter was called in boolean contexts. This make subsequent changes in
a series where we further refactor the hook API clearer, as we won't
conflate wanting to get the path of the hook with checking for its
existence.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-27 09:44:54 -07:00
Ævar Arnfjörð Bjarmason 5e3aba33da hook.[ch]: move find_hook() from run-command.c to hook.c
Move the find_hook() function from run-command.c to a new hook.c
library. This change establishes a stub library that's pretty
pointless right now, but will see much wider use with Emily Shaffer's
upcoming "configuration-based hooks" series.

Eventually all the hook related code will live in hook.[ch]. Let's
start that process by moving the simple find_hook() function over
as-is.

Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-27 09:44:54 -07:00
Junio C Hamano c042ad5ad5 Merge branch 'js/run-command-close-packs'
The run-command API has been updated so that the callers can easily
ask the file descriptors open for packfiles to be closed immediately
before spawning commands that may trigger auto-gc.

* js/run-command-close-packs:
  Close object store closer to spawning child processes
  run_auto_maintenance(): implicitly close the object store
  run-command: offer to close the object store before running
  run-command: prettify the `RUN_COMMAND_*` flags
  pull: release packs before fetching
  commit-graph: when closing the graph, also release the slab
2021-09-20 15:20:45 -07:00
Junio C Hamano a16dd13740 Merge branch 'ds/mergies-with-sparse-index'
Various mergy operations have been prepared to work efficiently
with the sparse index.

* ds/mergies-with-sparse-index:
  sparse-index: integrate with cherry-pick and rebase
  sequencer: ensure full index if not ORT strategy
  t1092: add cherry-pick, rebase tests
  merge-ort: expand only for out-of-cone conflicts
  merge: make sparse-aware with ORT
  diff: ignore sparse paths in diffstat
2021-09-20 15:20:45 -07:00
Junio C Hamano fd0d7036e0 Merge branch 'ab/retire-advice-config'
Code clean up to migrate callers from older advice_config[] based
API to newer advice_if_enabled() and advice_enabled() API.

* ab/retire-advice-config:
  advice: move advice.graftFileDeprecated squashing to commit.[ch]
  advice: remove use of global advice_add_embedded_repo
  advice: remove read uses of most global `advice_` variables
  advice: add enum variants for missing advice variables
2021-09-10 11:46:29 -07:00
Derrick Stolee a33806398a merge: make sparse-aware with ORT
Allow 'git merge' to operate without expanding a sparse index, at least
not immediately. The index still will be expanded in a few cases:

1. If the merge strategy is 'recursive', then we enable
   command_requires_full_index at the start of the merge_recursive()
   method. We expect sparse-index users to also have the 'ort' strategy
   enabled.

2. With the 'ort' strategy, if the merge results in a conflicted file,
   then we expand the index before updating the working tree. The loop
   that iterates over the worktree replaces index entries and tracks
   'origintal_cache_nr' which can become completely wrong if the index
   expands in the middle of the operation. This safety valve is
   important before that loop starts. A later change will focus this
   to only expand if we indeed have a conflict outside of the
   sparse-checkout cone.

3. Other merge strategies are executed as a 'git merge-X' subcommand,
   and those strategies are currently protected with the
   'command_requires_full_index' guard.

Some test updates are required, including a mistaken 'git checkout -b'
that did not specify the base branch, causing merges to be fast-forward
merges.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-09 15:49:04 -07:00
Johannes Schindelin 5a22a334cb run_auto_maintenance(): implicitly close the object store
Before spawning the auto maintenance, we need to make sure that we
release all open file handles to all the `.pack` files (and MIDX files
and commit-graph files and...) so that the maintenance process has the
freedom to delete those files.

So far, we did this manually every time before calling
`run_auto_maintenance()`. With the new `close_object_store` flag, we can
do that implicitly in that function, which is more robust because future
callers won't be able to forget to close the object store.

Note: this changes behavior slightly, as we previously _always_ closed
the object store, but now we only close the object store when actually
running the auto maintenance. In practice, this should not matter (if
anything, it might speed up operations where auto maintenance is
disabled).

Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-09 12:56:11 -07:00
Junio C Hamano 7b06222619 Merge branch 'rs/xopen-reports-open-failures'
Error diagnostics improvement.

* rs/xopen-reports-open-failures:
  use xopen() to handle fatal open(2) failures
  xopen: explicitly report creation failures
2021-09-08 13:30:32 -07:00
Junio C Hamano 669277c551 Merge branch 'cb/builtin-merge-format-string-fix'
Code clean-up.

* cb/builtin-merge-format-string-fix:
  builtin/merge: avoid -Wformat-extra-args from ancient Xcode
2021-08-30 16:06:03 -07:00
Junio C Hamano 8778fa8b4f Merge branch 'en/ort-becomes-the-default'
Use `ort` instead of `recursive` as the default merge strategy.

* en/ort-becomes-the-default:
  Update docs for change of default merge backend
  Change default merge backend from recursive to ort
2021-08-30 16:06:01 -07:00
Junio C Hamano aca13c2355 Merge branch 'en/merge-strategy-docs'
Documentation updates.

* en/merge-strategy-docs:
  Update error message and code comment
  merge-strategies.txt: add coverage of the `ort` merge strategy
  git-rebase.txt: correct out-of-date and misleading text about renames
  merge-strategies.txt: fix simple capitalization error
  merge-strategies.txt: avoid giving special preference to patience algorithm
  merge-strategies.txt: do not imply using copy detection is desired
  merge-strategies.txt: update wording for the resolve strategy
  Documentation: edit awkward references to `git merge-recursive`
  directory-rename-detection.txt: small updates due to merge-ort optimizations
  git-rebase.txt: correct antiquated claims about --rebase-merges
2021-08-30 16:06:01 -07:00
Junio C Hamano 7d0daf3f12 Merge branch 'en/pull-conflicting-options'
"git pull" had various corner cases that were not well thought out
around its --rebase backend, e.g. "git pull --ff-only" did not stop
but went ahead and rebased when the history on other side is not a
descendant of our history.  The series tries to fix them up.

* en/pull-conflicting-options:
  pull: fix handling of multiple heads
  pull: update docs & code for option compatibility with rebasing
  pull: abort by default when fast-forwarding is not possible
  pull: make --rebase and --no-rebase override pull.ff=only
  pull: since --ff-only overrides, handle it first
  pull: abort if --ff-only is given and fast-forwarding is impossible
  t7601: add tests of interactions with multiple merge heads and config
  t7601: test interaction of merge/rebase/fast-forward flags and options
2021-08-30 16:06:01 -07:00
René Scharfe 66e905b7dd use xopen() to handle fatal open(2) failures
Add and apply a semantic patch for using xopen() instead of calling
open(2) and die() or die_errno() explicitly.  This makes the error
messages more consistent and shortens the code.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-25 14:39:08 -07:00
Ben Boeckel ed9bff0817 advice: remove read uses of most global `advice_` variables
In c4a09cc9cc (Merge branch 'hw/advise-ng', 2020-03-25), a new API for
accessing advice variables was introduced and deprecated `advice_config`
in favor of a new array, `advice_setting`.

This patch ports all but two uses which read the status of the global
`advice_` variables over to the new `advice_enabled` API. We'll deal
with advice_add_embedded_repo and advice_graft_file_deprecated
separately.

Signed-off-by: Ben Boeckel <mathstuf@gmail.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-25 12:07:52 -07:00
Carlo Marcelo Arenas Belón 00e302da76 builtin/merge: avoid -Wformat-extra-args from ancient Xcode
d540b70c85 (merge: cleanup messages like commit, 2019-04-17) adds
a way to change part of the helper text using a single call to
strbuf_add_commented_addf but with two formats with varying number
of parameters.

this trigger a warning in old versions of Xcode (ex 8.0), so use
instead two independent calls with a matching number of parameters

Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-09 09:48:01 -07:00
Elijah Newren 6a5fb96672 Change default merge backend from recursive to ort
There are a few reasons to switch the default:
  * Correctness
  * Extensibility
  * Performance

I'll provide some summaries about each.

=== Correctness ===

The original impetus for a new merge backend was to fix issues that were
difficult to fix within recursive's design.  The success with this goal
is perhaps most easily demonstrated by running the following:

  $ git grep -2 KNOWN_FAILURE t/ | grep -A 4 GIT_TEST_MERGE_ALGORITHM
  $ git grep test_expect_merge_algorithm.failure.success t/
  $ git grep test_expect_merge_algorithm.success.failure t/

In order, these greps show:

  * Seven sets of submodule tests (10 total tests) that fail with
    recursive but succeed with ort
  * 22 other tests that fail with recursive, but succeed with ort
  * 0 tests that pass with recursive, but fail with ort

=== Extensibility ===

Being able to perform merges without touching the working tree or index
makes it possible to create new features that were difficult with the
old backend:

  * Merging, cherry-picking, rebasing, reverting in bare repositories...
    or just on branches that aren't checked out.

  * `git diff AUTO_MERGE` -- ability to see what changes the user has
    made to resolve conflicts so far (see commit 5291828df8 ("merge-ort:
    write $GIT_DIR/AUTO_MERGE whenever we hit a conflict", 2021-03-20)

  * A --remerge-diff option for log/show, used to show diffs for merges
    that display the difference between what an automatic merge would
    have created and what was recorded in the merge.  (This option will
    often result in an empty diff because many merges are clean, but for
    the non-clean ones it will show how conflicts were fixed including
    the removal of conflict markers, and also show additional changes
    made outside of conflict regions to e.g. fix semantic conflicts.)

  * A --remerge-diff-only option for log/show, similar to --remerge-diff
    but also showing how cherry-picks or reverts differed from what an
    automatic cherry-pick or revert would provide.

The last three have been implemented already (though only one has been
submitted upstream so far; the others were waiting for performance work
to complete), and I still plan to implement the first one.

=== Performance ===

I'll quote from the summary of my final optimization for merge-ort
(while fixing the testcase name from 'no-renames' to 'few-renames'):

                               Timings

                                          Infinite
                 merge-       merge-     Parallelism
                recursive    recursive    of rename    merge-ort
                 v2.30.0      current     detection     current
                ----------   ---------   -----------   ---------
few-renames:      18.912 s    18.030 s     11.699 s     198.3 ms
mega-renames:   5964.031 s   361.281 s    203.886 s     661.8 ms
just-one-mega:   149.583 s    11.009 s      7.553 s     264.6 ms

                           Speedup factors

                                          Infinite
                 merge-       merge-     Parallelism
                recursive    recursive    of rename
                 v2.30.0      current     detection    merge-ort
                ----------   ---------   -----------   ---------
few-renames:        1           1.05         1.6           95
mega-renames:       1          16.5         29           9012
just-one-mega:      1          13.6         20            565

And, for partial clone users:

             Factor reduction in number of objects needed

                                          Infinite
                 merge-       merge-     Parallelism
                recursive    recursive    of rename
                 v2.30.0      current     detection    merge-ort
                ----------   ---------   -----------   ---------
mega-renames:       1            1            1          181.3

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-05 15:35:02 -07:00
Elijah Newren 81483fe613 Update error message and code comment
There were two locations in the code that referred to 'merge-recursive'
but which were also applicable to 'merge-ort'.  Update them to more
general wording.

Acked-by: Derrick Stolee <dstolee@microsoft.com>
Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-05 08:57:40 -07:00
Junio C Hamano 5fef3b15db Merge branch 'pb/merge-autostash-more'
The local changes stashed by "git merge --autostash" were lost when
the merge failed in certain ways, which has been corrected.

* pb/merge-autostash-more:
  merge: apply autostash if merge strategy fails
  merge: apply autostash if fast-forward fails
  Documentation: define 'MERGE_AUTOSTASH'
  merge: add missing word "strategy" to a message
2021-08-04 13:28:54 -07:00
Andrzej Hunt 8c05e42c7a builtin/merge: free found_ref when done
merge_name() calls dwim_ref(), which allocates a new string into
found_ref. Therefore add a free() to avoid leaking found_ref.

LSAN output from t0021:

Direct leak of 16 byte(s) in 1 object(s) allocated from:
    #0 0x486804 in strdup ../projects/compiler-rt/lib/asan/asan_interceptors.cpp:452:3
    #1 0xa8beb8 in xstrdup wrapper.c:29:14
    #2 0x954054 in expand_ref refs.c:671:12
    #3 0x953cb6 in repo_dwim_ref refs.c:644:22
    #4 0x5d3759 in dwim_ref refs.h:162:9
    #5 0x5d3759 in merge_name builtin/merge.c:517:6
    #6 0x5d3759 in collect_parents builtin/merge.c:1214:5
    #7 0x5cf60d in cmd_merge builtin/merge.c:1458:16
    #8 0x4ce83e in run_builtin git.c:475:11
    #9 0x4ccafe in handle_builtin git.c:729:3
    #10 0x4cb01c in run_argv git.c:818:4
    #11 0x4cb01c in cmd_main git.c:949:19
    #12 0x6bdbfd in main common-main.c:52:11
    #13 0x7f0430502349 in __libc_start_main (/lib64/libc.so.6+0x24349)

SUMMARY: AddressSanitizer: 16 byte(s) leaked in 1 allocation(s).

Signed-off-by: Andrzej Hunt <andrzej@ahunt.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-26 12:19:20 -07:00
Philippe Blain e082631e51 merge: apply autostash if merge strategy fails
Since 'git merge' learned '--autostash' in a03b55530a (merge: teach
--autostash option, 2020-04-07), 'cmd_merge', once it is determined that
we have to create a merge commit, calls 'create_autostash' if
'--autostash' is given.

As explained in a03b55530a, and made more abvious by the tests added in
that commit, the autostash is then applied if the merge succeeds, either
directly or by committing (after conflict resolution or if '--no-commit'
was given), or if the merge is aborted with 'git merge --abort'. In some
other cases, like the user calling 'git reset --merge' or 'git merge
--quit', the autostash is not applied, but saved in the stash list.

However, there exists a scenario that creates an autostash but does not
apply nor save it to the stash list: if the chosen merge strategy
completely fails to handle the merge, i.e. 'try_merge_strategy' returns
2.

Apply the autostash in that case also. An easy way to test that is to
try to merge more than two commits but explicitely ask for the 'recursive'
merge strategy.

Signed-off-by: Philippe Blain <levraiphilippeblain@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-23 15:45:40 -07:00
Philippe Blain 12510bd5da merge: apply autostash if fast-forward fails
Since 'git merge' learned '--autostash' in a03b55530a (merge: teach
--autostash option, 2020-04-07), 'cmd_merge', in the fast-forward case,
calls 'create_autostash' before calling 'checkout_fast_forward' if
'--autostash' is given.

However, if 'checkout_fast_forward' fails, the autostash is not applied
to the working tree, nor saved in the stash list, since the code simply
calls 'goto done'.

Be more helpful to the user by applying the autostash in that case.

An easy way to test a failing fast-forward is when we are merging a
branch that has a tracked file that conflicts with an untracked file in
the working tree.

Signed-off-by: Philippe Blain <levraiphilippeblain@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-23 15:45:38 -07:00
Philippe Blain 9938f30d13 merge: add missing word "strategy" to a message
The variable 'best_strategy' holds the name of the merge strategy that
resulted in fewer conflicts, if several strategies were tried. When
that's the case but the best strategy was not the first one tried, we
inform the user which strategy was the "best" one before recreating the
merge and leaving the conflicted files in the tree.

This informational message is missing the word "strategy", so it shows
something like:

    Using the recursive to prepare resolving by hand.

Fix that.

Signed-off-by: Philippe Blain <levraiphilippeblain@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-23 15:45:33 -07:00
Alex Henrie 3d5fc24dae pull: abort if --ff-only is given and fast-forwarding is impossible
The warning about pulling without specifying how to reconcile divergent
branches says that after setting pull.rebase to true, --ff-only can
still be passed on the command line to require a fast-forward. Make that
actually work.

Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
[en: updated tests; note 3 fixes and 1 new failure]
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-20 21:43:12 -07:00
Junio C Hamano b03709eae7 Merge branch 'ah/merge-usage-i18n-fix'
i18n update.

* ah/merge-usage-i18n-fix:
  merge: don't translate literal commands
2021-06-10 12:04:23 +09:00
Alex Henrie a30e43f61a merge: don't translate literal commands
These strings have not been modified in any translation, nor should they
be.

Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-16 13:00:28 +09:00
Josh Soref ad9322da03 merge: fix swapped "up to date" message components
The rewrite of git-merge from shell to C in 1c7b76be7d (Build in merge,
2008-07-07) accidentally transformed the message:

    Already up-to-date. (nothing to squash)

to:

    (nothing to squash)Already up-to-date.

due to reversed printf() arguments. This problem has gone unnoticed
despite being touched over the years by 7f87aff22c (Teach/Fix pull/fetch
-q/-v options, 2008-11-15) and bacec47845 (i18n: git-merge basic
messages, 2011-02-22), and tangentially by bef4830e88 (i18n: merge: mark
messages for translation, 2016-06-17) and 7560f547e6 (treewide: correct
several "up-to-date" to "up to date", 2017-08-23).

Fix it by restoring the message to its intended order. While at it, help
translators out by avoiding "sentence Lego".

[es: rewrote commit message]

Co-authored-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Josh Soref <jsoref@gmail.com>
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-03 14:14:58 +09:00
Eric Sunshine 80cde95eec merge(s): apply consistent punctuation to "up to date" messages
Although the various "Already up to date" messages resulting from merge
attempts share identical phrasing, they use a mix of punctuation ranging
from "." to "!" and even "Yeeah!", which leads to extra work for
translators. Ease the job of translators by settling upon "." as
punctuation for all such messages.

While at it, take advantage of printf_ln() to further ease the
translation task so translators need not worry about line termination,
and fix a case of missing line termination in the (unused)
merge_ort_nonrecursive() function.

Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-03 14:14:56 +09:00
René Scharfe ca56dadb4b use CALLOC_ARRAY
Add and apply a semantic patch for converting code that open-codes
CALLOC_ARRAY to use it instead.  It shortens the code and infers the
element size automatically.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-13 16:00:09 -08:00
Junio C Hamano aac006aa99 Merge branch 'so/log-diff-merge'
"git log" learned a new "--diff-merges=<how>" option.

* so/log-diff-merge: (32 commits)
  t4013: add tests for --diff-merges=first-parent
  doc/git-show: include --diff-merges description
  doc/rev-list-options: document --first-parent changes merges format
  doc/diff-generate-patch: mention new --diff-merges option
  doc/git-log: describe new --diff-merges options
  diff-merges: add '--diff-merges=1' as synonym for 'first-parent'
  diff-merges: add old mnemonic counterparts to --diff-merges
  diff-merges: let new options enable diff without -p
  diff-merges: do not imply -p for new options
  diff-merges: implement new values for --diff-merges
  diff-merges: make -m/-c/--cc explicitly mutually exclusive
  diff-merges: refactor opt settings into separate functions
  diff-merges: get rid of now empty diff_merges_init_revs()
  diff-merges: group diff-merge flags next to each other inside 'rev_info'
  diff-merges: split 'ignore_merges' field
  diff-merges: fix -m to properly override -c/--cc
  t4013: add tests for -m failing to override -c/--cc
  t4013: support test_expect_failure through ':failure' magic
  diff-merges: revise revs->diff flag handling
  diff-merges: handle imply -p on -c/--cc logic for log.c
  ...
2021-02-05 16:40:44 -08:00
Sergey Organov 09322b1da9 diff-merges: new function diff_merges_suppress()
This function sets all the relevant flags to disabled state, so that
no code that checks only one of them get it wrong.

Then we call this new function everywhere where diff merges output
suppression is needed.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-21 13:47:31 -08:00
Junio C Hamano a1f95951ef Merge branch 'en/merge-ort-api-null-impl'
Preparation for a new merge strategy.

* en/merge-ort-api-null-impl:
  merge,rebase,revert: select ort or recursive by config or environment
  fast-rebase: demonstrate merge-ort's API via new test-tool command
  merge-ort-wrappers: new convience wrappers to mimic the old merge API
  merge-ort: barebones API of new merge strategy with empty implementation
2020-11-18 13:32:53 -08:00