From: Junio C Hamano Date: Wed, 18 Apr 2007 22:32:20 GMT Subject: Re: [PATCH] Fix overwriting of files when applying contextually independent diffs Message-ID: <7vtzvde2kr.fsf@assigned-by-dhcp.cox.net> In-Reply-To: <20070418215856.GA2477@steel.home> Alex Riesen 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.