Re: recur status on linux-2.6

From: Junio C Hamano <junkio@cox.net>
Date: Aug 22, 2006, 08:27 UTC
Message-ID: <7virklp438.fsf@assigned-by-dhcp.cox.net>
In-Reply-To: <20060819104630.GA5213@c165.ib.student.liu.se>

Fredrik Kuivinen <freku045@student.liu.se> writes:

Show 16 quoted lines

> On Sun, Aug 13, 2006 at 03:54:19PM +0200, Johannes Schindelin wrote:
>> Hi,
>> 
>> I tested git-merge-recur vs. git-merge-recursive on the linux-2.6 
>> repository last night. It contains 2298 two-head merges. _All_ of them 
>> come out identically with -recur as compared to -recursive (looking at 
>> the resulting index only).
>
> After the latest updates to git-merge-recur it passes all the tests I
> have too.
>  
>> That was the good news. The bad news is: it _seems_, that -recur is only 
>> about 6x faster than -recursive, not 10x, and this number becomes smaller, 
>> the longer the merge takes. So I see a startup effect here, probably.
>
> That is a quite nice improvement anyway :)

Maybe we should welcome Linus back with a surprise change that makes recur take over recursive ;-).

Well, maybe not *that* fast.

Here is what I have in mind.

 * Not in too distant future, like this weekend, we would:

   - remove "TEST" at toplevel;

   - merge the C merge-recur work in "master".

   At this stage, people still have to ask for "recur" by either
   explicitly saying "-s recur" or by exporting the environment
   variable GIT_USE_RECUR_FOR_RECURSIVE=YesPlease; git
   developers are encouraged to use this while running tests and
   production.

 * Before stabilization for 1.4.3, we would:

   - rename merge-recursive to merge-recursive-old and
     merge-recur to merge-recursive.

   - we remove GIT_USE_RECUR_FOR_RECURSIVE hack.

   - we make --no-python in t/ directory no-op and only test C
     recursive implementation by default.

   After this, people who would want to keep using the original
   recursive have to ask for it by "-s recursive-old".

 * We release 1.4.3 with C recursive as the default merge
   strategy.

I am not at this moment thinking about removing recursive in Python altogether. We still have a few contrib scripts (p4import and gitview) that are in Python, so doing that would not remove our dependency on Python anyway.