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* bug with git-diff --quiet
@ 2014-01-23  2:45 IWAMOTO Toshihiro
  2014-01-25  4:03 ` Duy Nguyen
  2014-01-25  6:46 ` [PATCH 1/3] Move diffcore_skip_stat_unmatch core logic out for reuse later Nguyễn Thái Ngọc Duy
  0 siblings, 2 replies; 12+ messages in thread
From: IWAMOTO Toshihiro @ 2014-01-23  2:45 UTC (permalink / raw)
  To: git

I found "git-diff --quiet" returns a zero exit status even if there's
a change.  The following sequence reproduces the bug:

  $ mkdir foo
  $ cd foo
  $ git init
  $ echo a > a.txt
  $ echo b >b.txt
  $ git add ?.txt
  $ git commit
  $ echo b >> b.txt
  $ touch a.txt
  $ git diff --quiet; echo $?
  
Interestingly, if you issue "git-diff --quiet" again, it returns the
expected exit status 1.

The problem is in the optimization code in run_diff_files().  The
function finds a.txt has different stat(2) data from .git/index and
calls diff_change(), which sets DIFF_OPT_HAS_CHANGES.  As the flag
makes diff_can_quit_early() return 1, run_diff_files()'s loop finishes
without calling diff_change() for b.txt.

Then, diffcore_std() examines diff_queued_diff and clears
DIFF_OPT_HAS_CHANGES, because a.txt is unchanged.
This is how a change in b.txt is ignored by git-diff --quiet.

Here's a obvious fix for this bug, but I think you can find a better
fix. Thanks in advance.


diff --git a/diff-lib.c b/diff-lib.c
index 346cac6..0b8c58d 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -105,9 +105,6 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 		int changed;
 		unsigned dirty_submodule = 0;
 
-		if (diff_can_quit_early(&revs->diffopt))
-			break;
-
 		if (!ce_path_match(ce, &revs->prune_data))
 			continue;
 
--
IWAMOTO Toshihiro

^ permalink raw reply related	[flat|nested] 12+ messages in thread

end of thread, other threads:[~2014-01-31 16:17 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-01-23  2:45 bug with git-diff --quiet IWAMOTO Toshihiro
2014-01-25  4:03 ` Duy Nguyen
2014-01-25  6:46 ` [PATCH 1/3] Move diffcore_skip_stat_unmatch core logic out for reuse later Nguyễn Thái Ngọc Duy
2014-01-25  6:46   ` [PATCH 2/3] diff: do not quit early on stat-dirty files Nguyễn Thái Ngọc Duy
2014-01-25  6:46   ` [PATCH 3/3] diff: turn off skip_stat_unmatch on "diff --cached" Nguyễn Thái Ngọc Duy
2014-01-27 22:59     ` [PATCH v2 3/3] diff: turn skip_stat_unmatch on selectively Nguyễn Thái Ngọc Duy
2014-01-27 23:45       ` Junio C Hamano
2014-01-28 22:51         ` Junio C Hamano
2014-01-28 23:52           ` Duy Nguyen
2014-01-29 19:25             ` Junio C Hamano
2014-01-30  5:36               ` Duy Nguyen
2014-01-31 16:17                 ` Junio C Hamano

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