[PATCH 1 of 3] localrepo: reuse parent manifest in commitctx if no files have changed

[Peter Arrenbrecht]

On Wed, May 4, 2011 at 10:57 PM, Christian Ebert <blacktrash at gmx.net> wrote:
> * Benoit Boissinot on Tuesday, May 03, 2011 at 18:21:44 +0200
>> On Mon, May 2, 2011 at 7:23 PM, Peter Arrenbrecht
>> <peter.arrenbrecht at gmail.com> wrote:
>>> # HG changeset patch
>>> # User Peter Arrenbrecht <peter.arrenbrecht at gmail.com>
>>> # Date 1304356829 -7200
>>> localrepo: reuse parent manifest in commitctx if no files have changed
>>>
>>> This speeds up the in-memory version of debugbuilddag that I'm
>>> working on considerably for the case where we want to build just
>>> a 00changelog.i (for discovery tests, for instance).
>>>
>>> There are a couple of test changes because node ids in tests
>>> have changed.
>>
>> I don't understand why they would change, could you explain? (they are
>> not related to debugbuilddag, right?)
>
> Did I miss the explanation, perhaps on irc? If someone could take
> the time to give some hints as to why this happens, I'd be very
> grateful.

Sorry, I had to look after the kids these past two days. One case is
when mq applies an empty patch. Another is csets that change only the
named branch. But I'll look into it in a bit more detail today.
-parren