Re: [PATCH] diffcore-rename: favour identical basenames

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Jun 21, 2007, 18:24 UTC
Message-ID: <alpine.LFD.0.98.0706211118420.3593@woody.linux-foundation.org>
In-Reply-To: <7vfy4lw5yk.fsf@assigned-by-dhcp.pobox.com>

On Thu, 21 Jun 2007, Junio C Hamano wrote:

Show 6 quoted lines

> 
> This is not an example to draw very useful conclusions, is it?
> 
> The heuristics to say '-pc => common' is a more likely rename
> than '-obscure-arch => common' heavily depends on human
> intelligence in the context

Oh, absolutely.

I'm just saying that *if* you see two equally weighed content moves, if you then prefer the one that has more in common with the name, that's likely the right choice.

In the actual example I gave, there was no ambiguity: the file contents were very obvious. But let's sat that you happened to have an example of two files with 100% identical content that moved, and you had the files

	-arch/i386/kernel/pci-pc.c
	-arch/alpha/kernel/pci-pc.c
	+arch/i386/kernel/pci/common.c
	+arch/alpha/kernel/pci/common.c

to match up, how would you do it? Again: they're all identical files: we can obviously agree that two files got renamed, but what is the pairing.

I'd suggest that if you do it by matching up the similarity of the filenames (not necessarily "exact same basename"), you'd actually catch it. In this case, they all have "pci" in them, but the "alpha" similarity would make you select the right one.

Similarly, in some other cases, the "pci" might be the thing they have in common, and might be the thing that decides that "oh, those two filenames look like they might be more of a better pair".

And yes, all of this would trigger only if the file data content match is non-conclusive. The file data is *more* important, but that doesn't mean that the file name similarity is *totally* unimportant either.

			Linus