This is the bug that just won't die; there always seems to be another
form of it somewhere. See the commit message of 55f39cf755 ("merge:
fix misleading pre-merge check documentation", 2018-06-30) for a more
detailed explanation), but in short:
<quick summary>
builtin/merge.c contains this important requirement for merge
strategies:
...the index must be in sync with the head commit. The strategies are
responsible to ensure this.
This condition is important to enforce because there are two likely
failure cases when the index isn't in sync with the head commit:
* we silently throw away changes the user had staged before the merge
* we accidentally (and silently) include changes in the merge that
were not part of either of the branches/trees being merged
Discarding users' work and mis-merging are both bad outcomes, especially
when done silently, so naturally this rule was stated sternly -- but,
unfortunately totally ignored in practice unless and until actual bugs
were found. But, fear not: the bugs from this were fixed in commit
ee6566e8d7 ("[PATCH] Rewrite read-tree", 2005-09-05)
through a rewrite of read-tree (again, commit 55f39cf755 has a more
detailed explanation of how this affected merge). And it was fixed
again in commit
160252f816 ("git-merge-ours: make sure our index matches HEAD", 2005-11-03)
...and it was fixed again in commit
3ec62ad9ff ("merge-octopus: abort if index does not match HEAD", 2016-04-09)
...and again in commit
65170c07d4 ("merge-recursive: avoid incorporating uncommitted changes in a merge", 2017-12-21)
...and again in commit
eddd1a411d ("merge-recursive: enforce rule that index matches head before merging", 2018-06-30)
...with multiple testcases added to the testsuite that could be
enumerated in even more commits.
Then, finally, in a patch in the same series as the last fix above, the
documentation about this requirement was fixed in commit 55f39cf755
("merge: fix misleading pre-merge check documentation", 2018-06-30), and
we all lived happily ever after...
</quick summary>
Unfortunately, "ever after" apparently denotes a limited time and it
expired today. The merge-recursive rule to enforce that index matches
head was at the beginning of merge_trees() and would only trigger when
opt->call_depth was 0. Since merge_recursive() doesn't call
merge_trees() until after returning from recursing, this meant that the
check wasn't triggered by merge_recursive() until it had first finished
all the intermediate merges to create virtual merge bases. That is a
potentially HUGE amount of computation (and writing of intermediate
merge results into the .git/objects directory) before it errors out and
says, in effect, "Sorry, I can't do any merging because you have some
local changes that would be overwritten."
Trying to enforce that all of merge_trees(), merge_recursive(), and
merge_recursive_generic() checked the index == head condition earlier
resulted in a bunch of broken tests. It turns out that
merge_recursive() has code to drop and reload the cache while recursing
to create intermediate virtual merge bases, but unfortunately that code
runs even when no recursion is necessary. This unconditional dropping
and reloading of the cache masked a few bugs:
* builtin/merge-recursive.c: didn't even bother loading the index.
* builtin/stash.c: feels like a fake 'builtin' because it repeatedly
invokes git subprocesses all over the place, mixed with other
operations. In particular, invoking "git reset" will reset the
index on disk, but the parent process that invoked it won't
automatically have its in-memory index updated.
* t3030-merge-recursive.h: this test has always been broken in that it
didn't make sure to make index match head before running. But, it
didn't care about the index or even the merge result, just the
verbose output while running. While commit eddd1a411d
("merge-recursive: enforce rule that index matches head before
merging", 2018-06-30) should have uncovered this broken test, it
used a test_must_fail wrapper around the merge-recursive call
because it was known that the merge resulted in a rename/rename
conflict. Thus, that fix only made this test fail for a different
reason, and since the index == head check didn't happen until after
coming all the way back out of the recursion, the testcase had
enough information to pass the one check that it did perform.
So, load the index in builtin/merge-recursive.c, reload the in-memory
index in builtin/stash.c, and modify the t3030 testcase to correctly
setup the index and make sure that the test fails in the expected way
(meaning it reports a rename/rename conflict). This makes sure that
all callers actually make the index match head. The next commit will
then enforce the condition that index matches head earlier so this
problem doesn't return in the future.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The assumption to work on the single "in-core index" instance has
been reduced from the library-ish part of the codebase.
* nd/the-index-final:
cache.h: flip NO_THE_INDEX_COMPATIBILITY_MACROS switch
read-cache.c: remove the_* from index_has_changes()
merge-recursive.c: remove implicit dependency on the_repository
merge-recursive.c: remove implicit dependency on the_index
sha1-name.c: remove implicit dependency on the_index
read-cache.c: replace update_index_if_able with repo_&
read-cache.c: kill read_index()
checkout: avoid the_index when possible
repository.c: replace hold_locked_index() with repo_hold_locked_index()
notes-utils.c: remove the_repository references
grep: use grep_opt->repo instead of explict repo argument
If $GITHEAD_1234abcd is set in the environment, we use its value as a
"better branch name" in generating conflict markers. However, we pick
these better names early in the process, and the return value from
getenv() is not guaranteed to stay valid.
Let's make a copy of the returned string. And to make memory management
easier, let's just always return an allocated string from
better_branch_name(), so we know that it must always be freed.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Use GIT_MAX_HEXSZ instead of GIT_SHA1_HEXSZ for an allocation so that it
is sufficiently large. Switch a comparison to use the_hash_algo to
determine the length of a hex object ID.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Spell the first word of such error messages in lowercase,
following the usual style.
Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert this function and the git merge-recursive subcommand to use
struct object_id.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We sometimes sprintf into fixed-size buffers when we know
that the buffer is large enough to fit the input (either
because it's a constant, or because it's numeric input that
is bounded in size). Likewise with strcpy of constant
strings.
However, these sites make it hard to audit sprintf and
strcpy calls for buffer overflows, as a reader has to
cross-reference the size of the array with the input. Let's
use xsnprintf instead, which communicates to a reader that
we don't expect this to overflow (and catches the mistake in
case we do).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Leaving only the function definitions and declarations so that any
new topic in flight can still make use of the old functions, replace
existing uses of the prefixcmp() and suffixcmp() with new API
functions.
The change can be recreated by mechanically applying this:
$ git grep -l -e prefixcmp -e suffixcmp -- \*.c |
grep -v strbuf\\.c |
xargs perl -pi -e '
s|!prefixcmp\(|starts_with\(|g;
s|prefixcmp\(|!starts_with\(|g;
s|!suffixcmp\(|ends_with\(|g;
s|suffixcmp\(|!ends_with\(|g;
'
on the result of preparatory changes in this series.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix warnings from 'make check'.
- These files don't include 'builtin.h' causing sparse to complain that
cmd_* isn't declared:
builtin/clone.c:364, builtin/fetch-pack.c:797,
builtin/fmt-merge-msg.c:34, builtin/hash-object.c:78,
builtin/merge-index.c:69, builtin/merge-recursive.c:22
builtin/merge-tree.c:341, builtin/mktag.c:156, builtin/notes.c:426
builtin/notes.c:822, builtin/pack-redundant.c:596,
builtin/pack-refs.c:10, builtin/patch-id.c:60, builtin/patch-id.c:149,
builtin/remote.c:1512, builtin/remote-ext.c:240,
builtin/remote-fd.c:53, builtin/reset.c:236, builtin/send-pack.c:384,
builtin/unpack-file.c:25, builtin/var.c:75
- These files have symbols which should be marked static since they're
only file scope:
submodule.c:12, diff.c:631, replace_object.c:92, submodule.c:13,
submodule.c:14, trace.c:78, transport.c:195, transport-helper.c:79,
unpack-trees.c:19, url.c:3, url.c:18, url.c:104, url.c:117, url.c:123,
url.c:129, url.c:136, thread-utils.c:21, thread-utils.c:48
- These files redeclare symbols to be different types:
builtin/index-pack.c:210, parse-options.c:564, parse-options.c:571,
usage.c:49, usage.c:58, usage.c:63, usage.c:72
- These files use a literal integer 0 when they really should use a NULL
pointer:
daemon.c:663, fast-import.c:2942, imap-send.c:1072, notes-merge.c:362
While we're in the area, clean up some unused #includes in builtin files
(mostly exec_cmd.h).
Signed-off-by: Stephen Boyd <bebarino@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* jn/merge-renormalize:
merge-recursive --renormalize
rerere: never renormalize
rerere: migrate to parse-options API
t4200 (rerere): modernize style
ll-merge: let caller decide whether to renormalize
ll-merge: make flag easier to populate
Documentation/technical: document ll_merge
merge-trees: let caller decide whether to renormalize
merge-trees: push choice to renormalize away from low level
t6038 (merge.renormalize): check that it can be turned off
t6038 (merge.renormalize): try checkout -m and cherry-pick
t6038 (merge.renormalize): style nitpicks
Don't expand CRLFs when normalizing text during merge
Try normalizing files to avoid delete/modify conflicts when merging
Avoid conflicts when merging branches with mixed normalization
Conflicts:
builtin/rerere.c
t/t4200-rerere.sh
This improves the usage output by adding builtin_merge_recursive_usage string
that follows the same pattern used by the other builtin commands.
The previous output for git merger-recursive was:
usage: merge-recursive <base>... -- <head> <remote> ...
Now the output is:
usage: git merge-recursive <base>... -- <head> <remote> ...
Since cmd_merge_recursive is used to handle four different commands we need
the %s in the usage string, so the following example:
$ git merge-subtree -h
Will output:
usage: git merge-subtree <base>... -- <head> <remote> ...
Signed-off-by: Thiago Farina <tfransosi@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach the merge-recursive strategy a --patience option to use the
"patience diff" algorithm, which tends to improve results when
cherry-picking a patch that reorders functions at the same time as
refactoring them.
To support this, struct merge_options and ll_merge_options gain an
xdl_opts member, so programs can use arbitrary xdiff flags (think
"XDF_IGNORE_WHITESPACE") in a git-aware merge.
git merge and git rebase can be passed the -Xpatience option to
use this.
[jn: split from --ignore-space patch; with documentation]
Signed-off-by: Justin Frankel <justin@cockos.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are two very similar blocks of code that recognize options for
the "recursive" merge strategy. Unify them.
No functional change intended.
Cc: Avery Pennarun <apenwarr@gmail.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach "git merge-recursive" a --renormalize option to enable the
merge.renormalize configuration. The --no-renormalize option can
be used to override it in the negative.
So in the future, you might be able to, e.g.:
git checkout -m -Xrenormalize otherbranch
or
git revert -Xrenormalize otherpatch
or
git pull --rebase -Xrenormalize
The bad part: merge.renormalize is still not honored for most
commands. And it reveals lots of places that -X has not been plumbed
in (so we get "git merge -Xrenormalize" but not much else).
NEEDSWORK: tests
Cc: Eyvind Bernhardsen <eyvind.bernhardsen@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This shrinks the top-level directory a bit, and makes it much more
pleasant to use auto-completion on the thing. Instead of
[torvalds@nehalem git]$ em buil<tab>
Display all 180 possibilities? (y or n)
[torvalds@nehalem git]$ em builtin-sh
builtin-shortlog.c builtin-show-branch.c builtin-show-ref.c
builtin-shortlog.o builtin-show-branch.o builtin-show-ref.o
[torvalds@nehalem git]$ em builtin-shor<tab>
builtin-shortlog.c builtin-shortlog.o
[torvalds@nehalem git]$ em builtin-shortlog.c
you get
[torvalds@nehalem git]$ em buil<tab> [type]
builtin/ builtin.h
[torvalds@nehalem git]$ em builtin [auto-completes to]
[torvalds@nehalem git]$ em builtin/sh<tab> [type]
shortlog.c shortlog.o show-branch.c show-branch.o show-ref.c show-ref.o
[torvalds@nehalem git]$ em builtin/sho [auto-completes to]
[torvalds@nehalem git]$ em builtin/shor<tab> [type]
shortlog.c shortlog.o
[torvalds@nehalem git]$ em builtin/shortlog.c
which doesn't seem all that different, but not having that annoying
break in "Display all 180 possibilities?" is quite a relief.
NOTE! If you do this in a clean tree (no object files etc), or using an
editor that has auto-completion rules that ignores '*.o' files, you
won't see that annoying 'Display all 180 possibilities?' message - it
will just show the choices instead. I think bash has some cut-off
around 100 choices or something.
So the reason I see this is that I'm using an odd editory, and thus
don't have the rules to cut down on auto-completion. But you can
simulate that by using 'ls' instead, or something similar.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
