Re: Parsing trailers

From: Jeff King <peff@peff.net>
Date: Jan 3, 2019, 07:07 UTC
Message-ID: <20190103070744.GA24149@sigill.intra.peff.net>
In-Reply-To: <CAFW+GMDazFSDzBrvzMqaPGwew=+CP7tw7G5FfDqcAUYd3qjPuQ@mail.gmail.com>

On Sun, Dec 23, 2018 at 02:41:20PM -0800, William Chargin wrote:

Show 7 quoted lines

> I'm interested in parsing the output of `git-interpret-trailers` in a
> script. I had hoped that the `--parse` option would make this easy, but
> it seems that the `trailer.separators` configuration option is used to
> specify both the input format (which separators may indicate a trailer)
> and the output format of `git interpret-trailers --parse`. Given that
> `trailer.separators` may contain any (non-NUL) characters, including
> whitespace, parsing the output is not straightforward.

IMHO this is a bug in --parse. It was always meant to give sane, normalized output, that you could parse with something like:

  [^:]+: .*

That's what "%(trailers:only)" does (even if the original separator was something else). It also trims any extra whitespace.

So I think it would be reasonable to:

  1. Add an --output-separator option. This should be uncontroversial.

  2. Make --parse imply "--output-separator=:". This might be more
     controversial, because it does change the output. But as I said
     above, I consider the current behavior to simply be a bug.

  3. (Optional) Add a "-z" option which uses "\0" both
     within and between trailer records. This obviously solves your
     problem without steps 1 and 2, but I think we should have a way to
     do it without relying on NULs, since they're harder to work with in
     some tools.

-Peff