From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jonathan Nieder <jrnieder@gmail.com>
Subject: Re: [PATCH] git-filter-branch: add --egrep-filter option
Date: Tue, 19 Apr 2011 03:01:43 -0500
Message-ID: <20110419080143.GA17915@elie>
References: <4DA8CBB0.6080103@rivulet.ca>
 <201104161016.51690.j6t@kdbg.org>
 <4DAA464E.7010804@rivulet.ca>
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Cc: Johannes Sixt <j6t@kdbg.org>, git@vger.kernel.org
To: Michael O'Cleirigh <michael.ocleirigh@rivulet.ca>
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Hi,

Michael O'Cleirigh wrote:

> After considering your comment I have to agree with you that it is a
> special case of index-filter and probably not useful/general for
> enough other cases to justify adding in a new command line option.

Now, why do you give up so easily? ;-)

Surely what your patch is hinting at is the possibility of an
--ls-tree-filter (for lack of a better name) that works with trees
without the overhead of unpacking them.  On the other hand I do agree
with Hannes that allowing only "egrep" is a bit overspecialized.

In practice I would have used something like

	--commit-filter='
		tree=$1 &&
		new_tree=$(
			git ls-tree $commit |
			egrep "$filter_egrep" |
			git mktree
		) &&
		shift &&
		git_commit_non_empty_tree "$new_tree" "$@"
	'

so another (simpler?) solution might be an entry for the EXAMPLES
section of the manual along these lines.

Ciao,
Jonathan