Re: [PATCH 0/3] Teach Git about the patience diff algorithm

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Jan 7, 2009, 20:25 UTC
Message-ID: <alpine.LFD.2.00.0901071222300.3057@localhost.localdomain>
In-Reply-To: <1231359317.6011.12.camel@maia.lan>

On Thu, 8 Jan 2009, Sam Vilain wrote:

> 
> Whatever happens, the current deterministic diff algorithm needs to stay
> for generating patch-id's... those really can't be allowed to change.

Sure they can.

We never cache patch-id's over a long time. And we _have_ changed xdiff to modify the output of the patches before, quite regardless of any patience issues: see commit 9b28d55401a529ff08c709f42f66e765c93b0a20, which admittedly doesn't affect any _normal_ diffs, but can generate subtly different results for some cases.

It's true that we want the diff algorithm to be deterministic in the sense that over the run of a _single_ rebase operation, the diff between two files should give similar and deterministic results, but that's certainly true of patience diff too.

			Linus