Re: [PATCH 1/2] t5411: remove file after use to prevent overwriting

>
> Am 18.01.21 um 14:30 schrieb Jiang Xin:
> > From: Jiang Xin <zhiyou.jx@alibaba-inc.com>
> >
> > SZEDER reported that t5411 failed in Travis CI's s390x environment a
> > couple of times, and could be reproduced with '--stress' test on this
> > specific environment.  The test failure messages might look like this:
> >
> >     + test_cmp expect actual
> >     --- expect      2021-01-17 21:55:23.430750004 +0000
> >     +++ actual      2021-01-17 21:55:23.430750004 +0000
> >     @@ -1 +1 @@
> >     -<COMMIT-A> refs/heads/main
> >     +<COMMIT-A> refs/heads/maifatal: the remote end hung up unexpectedly
> >     error: last command exited with $?=1
> >     not ok 86 - proc-receive: not support push options (builtin protocol)
> >
> > The file 'actual' is filtered from the file 'out' which contains result
> > of 'git show-ref' command.  Due to the error messages from other process
> > is written into the file 'out' accidentally, t5411 failed.  SZEDER finds
> > the root cause of this issue:
> >
> >  - 'git push' is executed with its standard output and error redirected
> >    to the file 'out'.
> >
> >  - 'git push' executes 'git receive-pack' internally, which inherits
> >    the open file descriptors, so its output and error goes into that
> >    same 'out' file.
> >
> >  - 'git push' ends without waiting for the close of 'git-receive-pack'
> >    for some cases, and the file 'out' is reused for test of
> >    'git show-ref' afterwards.
> >
> >  - A mixture of the output of 'git show-ref' abd 'git receive-pack'
> >    leads to this issue.
> >
> > To resolve this issue, we can remove the file 'out' after use.  The
> > long-running 'git receive-pack' will not redirect its output to the new
> > created 'out' file which has a different file descriptor.
>
> On Windows, removing an open file is not possible and this...
>
> > diff --git a/t/t5411/test-0000-standard-git-push.sh b/t/t5411/test-0000-standard-git-push.sh
> > index 47b058af7e..694d8e8dc2 100644
> > --- a/t/t5411/test-0000-standard-git-push.sh
> > +++ b/t/t5411/test-0000-standard-git-push.sh
> > @@ -40,6 +40,8 @@ test_expect_success "git-push --atomic ($PROTOCOL)" '
> >               -e "/^To / { p; }" \
> >               -e "/^ ! / { p; }" \
> >               <out >actual &&
> > +     # Prevent accidential changes by the internal "receive-pack" process.
> > +     rm out &&
>
> ... would fail.