Re: git rev-list %an, %ae, %at bug in v1.7.10.1 and beyond

On Tue, May 22, 2012 at 03:13:09PM +1000, Bryan Turner wrote:

I went and spoke to the tester who made the original commit, and it
sounds like what he did was open .git/config with a text editor and
update the user.name directly. He then saved the file. His operating
system's code page was UTF-16LE, so I believe the file was saved in
that format. He then did the commit.

That doesn't make sense. Git will not read a config file in utf16
(again, because of the NULs). Nor can you store NULs with "git config
user.name ...". So I'm not sure how utf16 might have made it there.

That sort of behavior is pretty far outside the scope of anything git
can realistically be expected to handle (and I told the tester that as
well). That said, I'm interested that it "suddenly" broke, and also
that cat-file still appears to not think there's any problem.

Yeah, I'm worried that it's indicative of a bug that might affect other
cases.

I piped the output through xxd, for cat-file and rev-list. The
cat-file output is the same in both versions of git, and looks like
this:
auri:qa-resources.git bturner$ git cat-file -p
5c1ccdec5f84aa149a4978f729fdda70769f942f | xxd
0000000: 7472 6565 2064 6431 3733 6362 3730 6261  tree dd173cb70ba
0000010: 6161 6330 3762 6466 3430 3566 3465 3364  aac07bdf405f4e3d
0000020: 6231 3130 6537 6661 6664 3138 300a 7061  b110e7fafd180.pa
0000030: 7265 6e74 2030 3263 3738 6263 3339 6163  rent 02c78bc39ac
0000040: 3631 3932 3632 3362 6630 3830 6533 6532  6192623bf080e3e2
0000050: 6163 3839 3261 3466 3537 3634 630a 6175  ac892a4f5764c.au
0000060: 7468 6f72 2061 203c 6661 726d 6173 4061  thor a <farmas@a
0000070: 746c 6173 7369 616e 2e63 6f6d 3e20 3133  tlassian.com> 13
0000080: 3237 3837 3632 3232 202b 3131 3030 0a63  27876222 +1100.c
0000090: 6f6d 6d69 7474 6572 2061 203c 6661 726d  ommitter a <farm
00000a0: 6173 4061 746c 6173 7369 616e 2e63 6f6d  as@atlassian.com
00000b0: 3e20 3133 3237 3837 3632 3232 202b 3131  > 1327876222 +11
00000c0: 3030 0a0a 636f 6d6d 6974 2077 6974 6820  00..commit with
00000d0: 756e 6963 6f64 6520 6e61 6d65 0a         unicode name.

But I don't see any unicode at all here. The author and committer names
are just ascii 'a'. However, that seems to be the real problem. If I
create a commit with a single-letter name, I see some weirdness:

  $ git init
  $ echo content >foo && git add foo
  $ GIT_AUTHOR_NAME=a git commit -m msg
   Author:  <>
   1 file changed, 1 insertion(+)
   create mode 100644 foo

Uh oh, that's odd. And worse:

  $ git log -1 --format='|%an <%ae>|'
  | <>|

But in v1.7.10:

  $ git log -1 --format='|%an <%ae>|'
  |a [off-list ref]|

So there is definitely a bug. The unicode thing is a red herring, and if
there was any unicode at some point, git stripped it out when making the
commit. The real regression seems to be in single-character names.

I'll see if I can find the bug.

-Peff