Re: Serious bug with pretty format strings & empty bodies?

["René Scharfe" <rene.scharfe@lsrfire.ath.cx>]

Jonathan del Strother schrieb:
> I'm struggling to come up with a minimal test case that confirms this,
> but I seem to be hitting a bug in the pretty string formatter when
> trying to print bodies of commits that don't have bodies.
> 
> For example, on a private repository, I'm trying to print the subject
> & body of a commit.  This particular commit doesn't actually have a
> body, so I'm expecting to see this output :
> 
> =================
> commit 18d2480ab689b483ef1ebbdb3f7420904049ba0b
> Try to flush log files before terminating the app
> 
> =================
> 
> However, when I actually run the command, I get gibberish in place of %b :
> =================
> $ git rev-list -1- --pretty=format:"%s%n%b"
> 18d2480ab689b483ef1ebbdb3f7420904049ba0b
> commit 18d2480ab689b483ef1ebbdb3f7420904049ba0b
> Try to flush log files before terminating the app
> tree 57bc7cf30a10aee96251852125cf30fd2c81d7aa
> parent 04c833865828538315fcdf6e187da077869ce444
> author Jonathan del Strother <jon.delStrother@bestbefore.tv> 1197901755 +0000
> committer Jonathan del Strother <jon.delStrother@bestbefore.tv> 1197901755 +0000
> 
> Check that ThreadWorker's work method actually returns a value with
> method signatures
> =================
> 
> So here you can see that the full details of a different commit is
> appearing in place of the requested commit's (empty) body.  Rerunning
> the rev-list produces the same output - the same string appears in
> place of %b every time, but it's different for each commit.  Often you
> only get a small fragment of another commit's message, rather than the
> full commit as seen above.
> 
> When I use --pretty=full, it works fine.
> 
> This appears in quite a few places in my repository's history.
> Repacking the repo semi-fixes it - I still get junk bodies, but not
> quite so many.
> 
> It doesn't always happen when a commit message body is empty, but I've
> never seen it happen where the message body has something in.
> 
> This happens with both git 1.5.3.7 and 1.5.4.rc0.1162.g3bfea, though
> the output is slightly different - the former has a number of
> <unknown> markers in it.  This is on OS X 10.5.1

That's strange.  Could you check if this happens with e52a5de, too?
That's the commit that introduced --pretty=format.  If it doesn't, could
you then please try to bisect the bug?

How many '<unknown>' markers are there in the output of version 1.5.3.7
(and e52a5de)?  One per %b?  Are they the only output or are they
combined with parts of unrelated commits, too?

Thanks,
René