Re: [PATCH] combine-diff: use textconv for combined diff format

From: Jakub Narebski <jnareb@gmail.com>
Date: Apr 16, 2011, 21:37 UTC
Message-ID: <m31v11yj37.fsf@localhost.localdomain>
In-Reply-To: <7vei52azbf.fsf@alter.siamese.dyndns.org>

Junio C Hamano <gitster@pobox.com> writes:

Show 18 quoted lines

> But that opens an old can of worms we should have opened and closed four
> years ago.
> 
> The header shows "diff --cc a" followed by "--- a/a" followed by "+++ b/a"
> before the hunk for a two-way merge.  But if we are to "combine and
> condense", another possibility is to show:
> 
>     diff --cc a/a b/a c/a
>     index bf7c788,fa9d23a,5d24d9f..cc69134
>     --- a/a
>     --- b/a
>     +++ c/a
>     @@@@ -74,26 -74,6 -74,29 +74,50 @@@@
>     ...
> 
> to keep the paths information.  I do not think anybody cared so far, and
> perhaps we should have done it when we introduced -c/--cc, but it is not
> at all worth changing now.

Such feature would greatly simplify gitweb code for dealing with combined diff (for a merge commit). It wouldn't have to jump through hoops[1] to get pre-image names to have correct link to pre-image...

This affects gitweb performance... in those rare case where we have rename in merge commit (gitweb is smart enough to do this dance only if there is rename in a merge).

Note that tree-diff doesn't help either - we have only post-image name.

[1]: fill_from_file_info subroutine, which in turn uses
     git_get_path_by_hash once per parent, which uses git-ls-tree

-- 
Jakub Narebski
Poland
ShadeHawk on #git