Re: [PATCH v2 2/2] Handle more file writes correctly in shared repos

From: Jeff King <peff@peff.net>
Date: Jan 7, 2016, 12:46 UTC
Message-ID: <20160107124608.GB14421@sigill.intra.peff.net>
In-Reply-To: <c03e5a9d367b76d8a249680c752b4c4d935e9b91.1452085713.git.johannes.schindelin@gmx.de>

On Wed, Jan 06, 2016 at 02:09:49PM +0100, Johannes Schindelin wrote:

Show 8 quoted lines

> In shared repositories, we have to be careful when writing files whose
> permissions do not allow users other than the owner to write them.
> 
> In particular, we force the marks file of fast-export and the FETCH_HEAD
> when fetching to be rewritten from scratch.
> 
> This commit does not touch the following users of fopen() that want to
> write files:

The patch looks good, and thanks for cataloguing the other cases.

Show 6 quoted lines

> - git am, when splitting mails (git-am correctly cleans up its directory
>   after finishing, so there is no need to share those files between users)
> 
> - git apply, when writing rejected hunks
> 
> - git fsck, when writing lost&found blobs

For these latter two, I had to ask myself "why not?". You gave such nice reasons for the other items in the list, I wondered what your reasoning was here. In the second case, for example, I think it would prevent a second shared user from running `git fsck --lost-found`, because we are likely to find the same "old" dangling objects and fail to write them.

I also wondered why we do not do the usual write-to-temp and rename in some of these cases, but that is not really relevant to your patch.

-Peff