Re: v2.11 new diff heuristic?

From: Jeff King <peff@peff.net>
Date: Nov 22, 2016, 17:55 UTC
Message-ID: <20161122175550.mlxzt3kgw3hj52qh@sigill.intra.peff.net>
In-Reply-To: <CAHd499AjXh1YnVgBj_8j0fgvOgOn53y+sPBBy6y7mSM-+dCyVw@mail.gmail.com>

On Tue, Nov 22, 2016 at 08:42:36AM -0600, Robert Dailey wrote:

Show 6 quoted lines

> I dug into the git diff documentation here:
> 
> https://git-scm.com/docs/git-diff
> 
> It mentions a "--compaction-heuristic" option. Is this the new
> heuristic outlined by the release notes? If not, which is it?

No. The docs on git-scm.com are only for released versions, so that is the "old" attempt at a similar feature from v2.9. The "new" one goes by the name "--indent-heuristic" (and "diff.indentHeuristic" in the config). It is not the default in v2.11, but it probably will become so in a future version.

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> Is the
> compaction heuristic compatible with the histogram diff algorithm? Is
> there a config option to turn this on all the time? For that matter,
> is this something I can keep on all the time or is it only useful in
> certain situations?
> 
> There's still so much more about this feature I would like to know.

Yes, you can keep it all the time. Yes, it's compatible with histogram (and patience); it happens as a separate post-processing step after the actual diff.

You can find more discussion about how it works in the commit message of 433860f3d0beb0c6f205290bd16cda413148f098.

-Peff