Re: git show loop

From: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Date: Mar 24, 2012, 12:42 UTC
Message-ID: <4F6DC151.9040707@in.waw.pl>
In-Reply-To: <4F6DB4E9.3090402@in.waw.pl>

On 03/24/2012 12:50 PM, Zbigniew Jędrzejewski-Szmek wrote:

> On 03/24/2012 11:05 AM, Julia Lawall wrote:
>> In linux, git show 60d9aa7 -U0 goes into an infinite loop.

Bisect points to
commit b810cbbde9232cbe9a3841edccc5b606bbd3a82e (refs/bisect/bad)
Author: Junio C Hamano <gitster@pobox.com>
Date:   Wed Jul 22 14:48:29 2009 -0700

     diff --cc: a lost line at the beginning of the file is shown 
incorrectly

Zbyszek

Show 6 quoted lines

> Yeah, I can confirm that with git version 1.7.10.rc1.225.gba57e.
>
> This doesn't happen everytime, some there's some race condition.
>
> unsigned long la; /* lookahead */
> is either 49 (works fine) or 18446744073709551615 (seems to hang).

I don't know the code enough to understand this, but obviously la is set to 0, and then decremented in the loop.

Show 22 quoted lines

> Zbyszek
>
> (gdb) bt
> #0  make_hunks (sline=0xb20360, cnt=161, num_parent=2, dense=1) at combine-diff.c:426
> #1  0x000000000049295a in show_patch_diff (elem=0x8d0020, num_parent=2, dense=1, working_tree_file=0, rev=0x7fffffffd7a0) at combine-diff.c:961
> #2  0x00000000004933cd in diff_tree_combined (sha1=0x82fc74 "`٪u\214", parents=0x7fffffffd620, dense=1, rev=0x7fffffffd7a0)
>      at combine-diff.c:1185
> #3  0x000000000049348f in diff_tree_combined_merge (commit=0x82fc70, dense=1, rev=0x7fffffffd7a0) at combine-diff.c:1209
> #4  0x00000000004c6913 in do_diff_combined (opt=0x7fffffffd7a0, commit=0x82fc70) at log-tree.c:731
> #5  0x00000000004c6a2f in log_tree_diff (opt=0x7fffffffd7a0, commit=0x82fc70, log=0x7fffffffd6d0) at log-tree.c:764
> #6  0x00000000004c6b7f in log_tree_commit (opt=0x7fffffffd7a0, commit=0x82fc70) at log-tree.c:808
> #7  0x0000000000444aa3 in cmd_log_walk (rev=0x7fffffffd7a0) at builtin/log.c:300
> #8  0x00000000004455ca in cmd_show (argc=3, argv=0x7fffffffe050, prefix=0x0) at builtin/log.c:510
> #9  0x0000000000405762 in run_builtin (p=0x795140, argc=3, argv=0x7fffffffe050) at git.c:308
> #10 0x00000000004058f5 in handle_internal_command (argc=3, argv=0x7fffffffe050) at git.c:467
> #11 0x0000000000405a0f in run_argv (argcp=0x7fffffffdf3c, argv=0x7fffffffdf30) at git.c:513
> #12 0x0000000000405b9c in main (argc=3, argv=0x7fffffffe050) at git.c:588
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