Re: [PATCH] Fix overwriting of files when applying contextually independent diffs

[Junio C Hamano <junkio@cox.net>]

Alex Riesen <raa.lkml@gmail.com> writes:

> Noticed by applying two diffs of different contexts to the same file.
>
> The check for existence of a file was wrong: the test assumed it was
> a directory and reset the errno (twice: directly and by calling
> lstat). So if an entry existed and was _not_ a directory no attempt
> was made to rename into it, because the errno (expected by renaming
> code) was already reset to 0. This resulted in error:
>
>     fatal: unable to write file file mode 100644
>
> For Linux, removing "errno = 0" is enough, as lstat wont modify errno
> if it was successful. The behavior should not be depended upon,
> though, so modify the "if" as well.
>
> The test simulates this situation.

Ok.  I briefly thought this might disable a more important
safety to refuse overwriting an untracked working tree file with
a creation patch, but that is caught much earlier in an
independent codepath already, so this should be safe to apply.

Thanks.