Re: [PATCH 4/4] cat-file: support --textconv/--filters in batch mode

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Aug 19, 2016, 12:59 UTC
Message-ID: <alpine.DEB.2.20.1608191450500.4924@virtualbox>
In-Reply-To: <xmqqbn0q6m4v.fsf@gitster.mtv.corp.google.com>

Hi Junio,

On Thu, 18 Aug 2016, Junio C Hamano wrote:

Show 24 quoted lines

> Johannes Schindelin <johannes.schindelin@gmx.de> writes:
> 
> > With this patch, --batch can be combined with --textconv or --filters.
> > For this to work, the input needs to have the form
> >
> > 	<object name><single white space><path>
> >
> > so that the filters can be chosen appropriately.
> >  --batch::
> >  --batch=<format>::
> >  	Print object information and contents for each object provided
> > -	on stdin.  May not be combined with any other options or arguments.
> > -	See the section `BATCH OUTPUT` below for details.
> > +	on stdin.  May not be combined with any other options or arguments
> > +	except `--textconv` or `--filters`, in which case the input lines
> > +	also need to specify the path, separated by white space.  See the
> > +	section `BATCH OUTPUT` below for details.
> 
> Makes sense.  This format still allows
> 
> 	HEAD:<path2> <path1>
> 
> i.e. the object name is taken from path2 but we forget it and
> pretend that the blob sits at path2, which is a good feature.

Correct.

Show 6 quoted lines

> If I am not mistaken, your cover letter alluded that it might be
> ideal to take "HEAD:<path>" (nothing else) as input, grab "<path>"
> and feed that to the filtering machinery, but you decided to stop
> short of doing that.  I actually think that it is the right thing to
> do for this feature to ignore the trailing :<path> in the object
> name, iow, I agree with the result from the feature design POV.

I actually decided against it only because it would uglify the code. From a user point of view, I am a bit annoyed having to say

	:README README
	:Makefile Makefile
	:main.c main.c
	[...]

> The only thing that somewhat is worrysome is what would happen to
> %(rest).

What would happen is that it would print out the path, as it is exactly that "rest" field that is used in the implementation, piggybacking on that very nice feature.

Of course, this means that you simply cannot send "SHA-1 path rest" to cat-file --batch and expect that to work. Should anybody need that in the future, they can give it a try themselves to patch cat-file.

Ciao, Dscho