Re: [RFC] new subcommand: git sync

From: Junio C Hamano <gitster@pobox.com>
Date: Feb 26, 2021, 22:31 UTC
Message-ID: <xmqq35xisbp3.fsf@gitster.g>
In-Reply-To: <87tupy7sx6.fsf@evledraar.gmail.com>

Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:

> B.t.w. you can probably speed up & simplify your script a lot by making
> use of IFS="" in the shell and not calling N for-each-ref commands when
> it seems to me that one invocation would do. Just dump the N fields you
> need split on some token, and split on that token in your loop.

A hidden gem in for-each-ref is its ability to quote the placeholder values in a language specific way, and that is to allow the --format to generate a script that can be eval'ed. E.g.

  $ git for-each-ref --shell \
    --format='doit %(authorname) %(subject)' refs/heads/ab/\* |
    head -n 3
  doit 'Ævar Arnfjörð Bjarmason' 'branch: show "HEAD detached" first ...'
  doit 'Ævar Arnfjörð Bjarmason' 'CoC: update to version 2.0 + local ...'
  doit 'Ævar Arnfjörð Bjarmason' 'config.mak.uname: remove unused NEE...'

so that you can prepare

	doit () {
		person=$1 subject=$2
		... do things on the branch data ...
	}

beforehand and then eval the output from the script you wrote with "git for-each-ref".