From: Andreas Ericsson <ae@op5.se>
To: Eric Raible <raible@gmail.com>
Cc: Git Mailing List <git@vger.kernel.org>
Subject: Re: Schrödinger's diff
Date: Tue, 07 Jul 2009 09:52:14 +0200 [thread overview]
Message-ID: <4A52FEAE.90705@op5.se> (raw)
In-Reply-To: <279b37b20907062353k34bca06erf035458e80933c8d@mail.gmail.com>
Eric Raible wrote:
> git version 1.6.3.2.1299.gee46c (msysgit)
>
> In trying to track down some annoying crlf corruption in a repo
> I have found a Schrödinger's diff. In other words it's unknown
> whether the diff will produce output or not on any particular run
> of the following script.
>
> Sometimes it does, and sometimes it doesn't (seems to be about
> 50/50). But either way in any given repo rerunning the git-diff will
> always give the same result.
>
I don't get the same result in the same repo, although it only
differs in 1-1.5% of the tests.
> Doing an "git ls-tree HEAD" gives an identical tree in both cases.
>
> Can anyone explain why the output to this is not deterministic?
On Linux with git version 1.6.3.3.354.g3b4cc
Pasting your commands into "repro.sh", but redirecting output from
git commit to /dev/null, and then running the following commands
has yielded 9 to 15 sample.$i files over 5 tries of the following:
sh repro.sh > correct
for i in $(seq 1 1000); do
sh repro.sh > sample && cmp sample correct >/dev/null || \
{ echo "fail $i" && cp sample sample.$i; };
done
> I'm at a complete loss.
>
Inserting "sync" between calls as shown below doesn't fix the issue
(although it drops from 9-15 to 4-10 fails on Linux; Not a very good
improvement and only two test-runs). I have no idea how it can behave
so strangely, and I refuse to believe that the ext3 fs driver allows
dirty reads.
> # Clean up from last run and start over
> rm -rf .git has-crlf
> git init
> git config core.autocrlf false
>
> # Add a "bad" file
> perl -e 'printf( "12%c%c", 0xd, 0xa )' > has-crlf
> git add has-crlf
> git commit -m"add crlf"
>
sync
> # I realize that switching is ill-advised, but I'm
> # trying to track down a possibly related problem...
> git config core.autocrlf true
>
sync
> # This sometimes produces output and sometimes it doesn't.
> # Either way rerunning just git-diff always gives the same result
> # as the first run in this repo.
> git diff
>
--
Andreas Ericsson andreas.ericsson@op5.se
OP5 AB www.op5.se
Tel: +46 8-230225 Fax: +46 8-230231
Considering the successes of the wars on alcohol, poverty, drugs and
terror, I think we should give some serious thought to declaring war
on peace.
next prev parent reply other threads:[~2009-07-07 7:52 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-07 6:53 Schrödinger's diff Eric Raible
2009-07-07 7:28 ` Johannes Sixt
2009-07-07 7:52 ` Andreas Ericsson [this message]
2009-07-07 17:36 ` Daniel Barkalow
2009-07-07 19:36 ` Jeff King
2009-07-07 19:48 ` Junio C Hamano
2009-07-07 19:54 ` Jeff King
2009-07-07 22:22 ` Junio C Hamano
2009-07-08 0:17 ` Eric Raible
2009-07-08 2:54 ` Junio C Hamano
2009-07-08 6:13 ` Eric Raible
2009-07-07 20:30 ` Eric Raible
2009-07-07 20:48 ` Jeff King
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