From: Daniel Barkalow <barkalow@iabervon.org>
Date: Sun, 16 Mar 2008 21:10:34 GMT
Subject: Re: [PATCH] Don't update unchanged merge entries
Message-ID: <alpine.LNX.1.00.0803161700430.19665@iabervon.org>
In-Reply-To: <alpine.LFD.1.00.0803161338100.3020@woody.linux-foundation.org>

On Sun, 16 Mar 2008, Linus Torvalds wrote:

> On Sun, 16 Mar 2008, Daniel Barkalow wrote:
> > 
> > While you're at it, you should at least fix the comment. I actually think 
> > it would be better to have update start out 0 and be set to CE_UPDATE 
> > after verify_uptodate() and verify_absent(), since those checks are what 
> > verifies that using CE_UPDATE is okay.
> 
> Well, I just made it match the old behavior. It used to be that the 
> copy_cache_entry() would clear the CE_UPDATE bit in the target 'merge' 
> entry, so I just cleared "update" there, the way we used to do it.
> 
> So now we actually *do* match the comment again - the bug was that we 
> didn't match it before due to it all being a bit too subtle.

Well, the top part of the comment suggests that this is just an 
optimization (don't bother to write out a file that you know is 
unchanged), when it's actually necessary for correctness (since we don't 
know if the working tree matches the old index).

	-Daniel
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