From: Ian Campbell <ijc@hellion.org.uk>
Date: Wed, 09 Aug 2017 07:43:18 GMT
Subject: Re: [PATCH 2/2] filter-branch: Handle rewritting (very) old style tags which lack tagger
Message-ID: <1502264598.2735.30.camel@hellion.org.uk>
In-Reply-To: <xmqqzib9ai63.fsf@gitster.mtv.corp.google.com>

On Tue, 2017-08-08 at 14:00 -0700, Junio C Hamano wrote:
> > @@ -540,6 +540,9 @@ if [ "$filter_tag_name" ]; then
> > >  			new_sha1=$( ( printf 'object %s\ntype commit\ntag %s\n' \
> > >  						"$new_sha1" "$new_ref"
> > >  				git cat-file tag "$ref" |
> > > > +				awk '/^tagger/	{ tagged=1 }
> > > > > +				     /^$/	{ if (!tagged && !done) { print "tagger Unknown <unknown@example.com> 0 +0000" } ; done=1 }
> > > > +				     //		{ print }' |
> > >  				sed -n \
> > >  				    -e '1,/^$/{
> > >  					  /^object /d
> 
> What the change wants to do makes perfect sense, but piping output
> from awk into sed looks somewhat gross.  Perhaps we'd want to roll
> what the existing sed script is trying to do into this new awk
> script?

I'm far from an awk guru but I think (unit tested in isolation only)
that such script would look something like (I also inverted/renamed
done into header since it seemed clearer):

    BEGIN    	    	    	    	    	    { header=1 }
    /^tagger /    	    	    	    	    { tagged=1 }
    /^$/    	    	    	    	    	    { if (!tagged && header) { print "tagger Unknown <    unknown@example.com    > 0 +0000" } ; header=0 }

    /^-----BEGIN PGP SIGNATURE-----/    	    { exit(0) }

    //    	    	    	    	    	    { if (!header || $0 !~ /^(object|type|tag )/) { print } }

    Ian.