Re: [PATCH] diff: add a config option to control orderfile

From: Jonathan Nieder <jrnieder@gmail.com>
Date: Sep 24, 2013, 19:36 UTC
Message-ID: <20130924193610.GO9464@google.com>
In-Reply-To: <20130924055419.GA11208@redhat.com>

Michael S. Tsirkin wrote:

> On Mon, Sep 23, 2013 at 02:37:29PM -0700, Jonathan Nieder wrote:

Show 13 quoted lines

>>  a) When asked to compute the patch-id of a seekable file, use the
>>     current streaming implementation until you notice a filename that
>>     is out of order.  Then start over with sorted hunks (for example
>>     building a table of offsets within the patch for each hunk to
>>     support this).
>>
>>     When asked to compute the patch-id of an unseekable file, stream
>>     to a temporary file under $GIT_DIR to get a seekable file.
>
> This can be computed in one pass: just keep two checksums around.
>
> But the result won't be stable: if you get same patch from two
> people one is ordered, the other isn't, you get two different checksums.

Sorry for the lack of clarity. In this case (a), I meant "sort the diff hunks and use the *old* patch-id definition with sorted hunks, which produces a stable result but requires random access.

However:

[...]

Show 7 quoted lines

>>  b) Unconditionally use the new patch-id definition that is stable
>>     under permutation of hunks.  If and when someone complains that
>>     this invalidates their old patch-ids, they can work on adding a
>>     nice interface for getting the old-style patch-ids.  I suspect it
>>     just wouldn't come up.
>
> That's certainly easy to implement.

Yes, (b) seems like the best option to me, for what it's worth.

Thanks again, Jonathan