Subject: Re: git and bzr

From: Aaron Bentley <[email-masked]>
Date: Tue, 28 Nov 2006 13:31:56 -0500

Jakub Narebski wrote:
>>I notice that blame has an option to limit the annotation to recent
>>history.  I can only assume that is for performance reasons.  bzr
>>annotate doesn't need a feature like that, because annotations are
>>explicit in bzr's storage format. 
> 
> 
> But you don't have content movement tracking.
> 
> 
>>                                  I expect that even if we were to 
>>extend annotate to track content across files, it would still be so fast
>>that we wouldn't need it.
> 
> 
> I think not.

There's no question that determining content movement could involve
opening a lot of revisions, but you wouldn't need to examine:

1. revisions that didn't alter any lines being examined
2. revisions that altered only the file in question
3. revisions with multiple parents, because any lines attributed to that
merge will be the outcome of conflict resolution.  (Other lines will be
attributed to one of the parents)

I'll admit though, that when I was thinking of this, I was thinking of
annotation-based merging, a scenario in which the number of lines being
examined is typically extremely low.

Aaron
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