48edf3a02a
There's an odd bug when "log --color-moved" is used with the combination
of "--cc --stat -p": the stat for merge commits is erroneously shown
with the diff of the _next_ commit.
The included test demonstrates the issue. Our history looks something
like this:
A-B-M--D
\ /
C
When we run "git log --cc --stat -p --color-moved" starting at D, we get
this sequence of events:
1. The diff for D is using -p, so diff_flush() calls into
diff_flush_patch_all_file_pairs(). There we see that o->color_moved
is in effect, so we point o->emitted_symbols to a static local
struct, causing diff_flush_patch() to queue the symbols instead of
actually writing them out.
We then do our move detection, emit the symbols, and clear the
struct. But we leave o->emitted_symbols pointing to our struct.
2. Next we compute the diff for M. This is a merge, so we use the
combined diff code. In find_paths_generic(), we compute the
pairwise diff between each commit and its parent. Normally this is
done with DIFF_FORMAT_NO_OUTPUT, since we're just looking for
intersecting paths. But since "--stat --cc" shows the first-parent
stat, and since we're computing that diff anyway, we enable
DIFF_FORMAT_DIFFSTAT for the first parent. This outputs the stat
information immediately, saving us from running a separate
first-parent diff later.
But where does that output go? Normally it goes directly to stdout,
but because o->emitted_symbols is set, we queue it. As a result, we
don't actually print the diffstat for the merge commit (yet), which
is wrong.
3. Next we compute the diff for C. We're actually showing a patch
again, so we end up in diff_flush_patch_all_file_pairs(), but this
time we have the queued stat from step 2 waiting in our struct.
We add new elements to it for C's diff, and then flush the whole
thing. And we see the diffstat from M as part of C's diff, which is
wrong.
So triggering the bug really does require the combination of all of
those options.
To fix it, we can simply restore o->emitted_symbols to NULL after
flushing it, so that it does not affect anything outside of
diff_flush_patch_all_file_pairs(). This intuitively makes sense, since
nobody outside of that function is going to bother flushing it, so we
would not want them to write to it either.
In fact, we could take this a step further and turn the local "esm"
struct into a non-static variable that goes away after the function
ends. However, since it contains a dynamically sized array, we benefit
from amortizing the cost of allocations over many calls. So we'll leave
it as static to retain that benefit.
But let's push the zero-ing of esm.nr into the conditional for "if
(o->emitted_symbols)" to make it clear that we do not expect esm to hold
any values if we did not just try to use it. With the code as it is
written now, if we did encounter such a case (which I think would be a
bug), we'd silently leak those values without even bothering to display
them. With this change, we'd at least eventually show them, and somebody
would notice.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git - fast, scalable, distributed revision control system
Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals.
Git is an Open Source project covered by the GNU General Public License version 2 (some parts of it are under different licenses, compatible with the GPLv2). It was originally written by Linus Torvalds with help of a group of hackers around the net.
Please read the file INSTALL for installation instructions.
Many Git online resources are accessible from https://git-scm.com/ including full documentation and Git related tools.
See Documentation/gittutorial.txt to get started, then see
Documentation/giteveryday.txt for a useful minimum set of commands, and
Documentation/git-.txt for documentation of each command.
If git has been correctly installed, then the tutorial can also be
read with man gittutorial or git help tutorial, and the
documentation of each command with man git-<commandname> or git help <commandname>.
CVS users may also want to read Documentation/gitcvs-migration.txt
(man gitcvs-migration or git help cvs-migration if git is
installed).
The user discussion and development of Git take place on the Git mailing list -- everyone is welcome to post bug reports, feature requests, comments and patches to git@vger.kernel.org (read Documentation/SubmittingPatches for instructions on patch submission). To subscribe to the list, send an email with just "subscribe git" in the body to majordomo@vger.kernel.org. The mailing list archives are available at https://public-inbox.org/git/, http://marc.info/?l=git and other archival sites.
Issues which are security relevant should be disclosed privately to the Git Security mailing list git-security@googlegroups.com.
The maintainer frequently sends the "What's cooking" reports that list the current status of various development topics to the mailing list. The discussion following them give a good reference for project status, development direction and remaining tasks.
The name "git" was given by Linus Torvalds when he wrote the very first version. He described the tool as "the stupid content tracker" and the name as (depending on your mood):
- random three-letter combination that is pronounceable, and not actually used by any common UNIX command. The fact that it is a mispronunciation of "get" may or may not be relevant.
- stupid. contemptible and despicable. simple. Take your pick from the dictionary of slang.
- "global information tracker": you're in a good mood, and it actually works for you. Angels sing, and a light suddenly fills the room.
- "goddamn idiotic truckload of sh*t": when it breaks