Re: [RFC PATCH 1/1] for-each-ref: add '--no-symbolic' option

From: Junio C Hamano <gitster@pobox.com>
Date: Sep 8, 2019, 22:34 UTC
Message-ID: <xmqq4l1mmn8i.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <xmqq8sqyn6ek.fsf@gitster-ct.c.googlers.com>

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

Show 12 quoted lines

> Jeff King <peff@peff.net> writes:
>
>> So in my mind there's an endgame we'd like to eventually reach where
>> the option added by your patch isn't needed anymore. But we're a long
>> way from that. And it's not entirely clear where we'd draw the line
>> anyway.
>
> All true and very good "thinking out loud".
>
>> So in the meantime, this seems like a useful thing, and it
>> wouldn't be a burden to carry it even if we eventually added
>> "--omit=%(symref)" or something.

We can introduce two new options, e.g. --(include|exclude)=<format> where

 * Without either, there is no filtering based on the placeholder
   expansion;

 * With only --include, only the refs for which <format> expands to
   non-empty are included.

 * With only --exclude, the refs for which <format> expands to
   non-empty are excluded (and everything else included).

 * With both --include and --exclude, only the refs for which the
   <format> for --include expands to non-empty are eligible to be
   included, but among them, the ones for which the <format> for
   --exclude expands to non-empty are discarded.

Then "--exclude=%(symref)" would be Eric's --no-symref, "--include=%(symref)" would be the opposite (i.e. "show only symbolic refs"), etc.

I guess with "%(if)...%(then)...%(else)...%(end)" you might be able to do either one of --include/--exclude without supporting the other, e.g. "--include='%(if)%(symref)%(then)%(else)not a symref%(end)" would be usable as "I do not want to see symrefs" in a system that supports only "--include" without "--exclude".