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Date:   Wed, 25 Jan 2017 15:05:23 -0500
From:   Jeff King <peff@peff.net>
To:     Junio C Hamano <gitster@pobox.com>
Cc:     git@vger.kernel.org
Subject: Re: [PATCH 12/12] receive-pack: avoid duplicates between our refs
 and alternates
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On Wed, Jan 25, 2017 at 12:02:30PM -0800, Junio C Hamano wrote:

> > +extract_ref_advertisement () {
> > +	perl -lne '
> > +		# \\ is there to skip capabilities after \0
> > +		/push< ([^\\]+)/ or next;
> > +		exit 0 if $1 eq "0000";
> > +		print $1;
> > +	'
> 
> Parsing TRACE_PACKET output?  Yuck.  But I think this has to do, as
> any other solution will bound to be uglier.

Agreed. My initial attempt was to just run "git receive-pack </dev/null"
and parse the advertisement. But then you have to parse pktlines. :)

> > +	# Notable things in this expectation:
> > +	#  - local refs are not de-duped
> > +	#  - .have does not duplicate locals
> > +	#  - .have does not duplicate itself
> > +	local=$(git -C fork rev-parse HEAD) &&
> > +	shared=$(git -C shared rev-parse only-shared) &&
> > +	cat >expect <<-EOF &&
> > +	$local refs/heads/master
> > +	$local refs/remotes/origin/HEAD
> > +	$local refs/remotes/origin/master
> > +	$shared .have
> > +	EOF
> 
> We may want to sort this thing and the extracted one when comparing;
> the order of the entries is not part of the feature we cast in stone.

True (and in fact the .have moved in the previous patch). I wondered,
though, if it might not be a reasonable thing for somebody to have to
look at the output and verify it when the order _does_ change.

I dunno.

-Peff