From: Daniel Barkalow Date: Sun, 16 Mar 2008 20:00:32 GMT Subject: Re: [PATCH] Don't update unchanged merge entries Message-ID: In-Reply-To: On Sun, 16 Mar 2008, Linus Torvalds wrote: > In commit 34110cd4e394e3f92c01a4709689b384c34645d8 ("Make 'unpack_trees()' > have a separate source and destination index") I introduced a really > stupid bug in that it would always add merged entries with the CE_UPDATE > flag set. That caused us to always re-write the file, even when it was > already up-to-date in the source index. > > Not only is that really stupid from a performance angle, but more > importantly it's actively wrong: if we have dirty state in the tree when > we merge, overwriting it with the result of the merge will incorrectly > overwrite that dirty state. > > This trivially fixes the problem - simply don't set the CE_UPDATE flag > when the merge result matches the old state. 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. -Daniel *This .sig left intentionally blank*