Please document Haskell team style Vcs-Git sytax

[Jonathan Nieder]

Russ Allbery wrote:

> If you want to do what vcswatch is doing (analyze the current code
> repository for Debian packaging for commits that haven't been uploaded),
> and the team is, like Haskell, using a single repository for all the
> packages, you need to be able to find that specific package in the
> repository to look for unreleased changes.

Thanks.  Once someone writes some proposed text, it seems like it would
be worth mentioning this kind of use case in it.

> Similarly, dgit presumably wants to be able to find the part of the
> repository that's used for packaging a specific package, and I assume Ian
> is thinking about doing some dark magic to make that work with the rest of
> dgit's workflow (although I don't know what that is, or how it would work
> with, e.g., dgit tagging).

*nod*

>> And similarly, what is the use case behind the other key/value pairs
>> described here?
>
> We don't know, but we've now had to add two different things we didn't
> anticipate, and so it seems like a reasonable assumption there may be
> more.

For command line options like "-b", I would be okay with following the
same model as last time and using space as a source of extensibility
(i.e., breaking compatibility).  So for that I wouldn't want to use
the bracket syntax.

For future settings in the same spirit as <path> that don't involve
command line options, or for command-line options that are okay to
ignore, the

  Vcs-Git-Whatsit: <whatsit>

approach should work okay.

So I'm thinking the bracketed path might be enough here, without need
for the additional complexity of in-field key/value pairs.

[...]
> Being able to clone a subdirectory of a Git repository would be lovely,
> speaking as someone who works at a company that insists on using a
> monorepo.

Interesting.  That's helpful context.

>            I think that's a pretty long-standing feature request, though.

No one's filed it at bugs.debian.org/git or https://crbug.com/git yet.
But there's a similar internal feature request at $DAYJOB.  Thanks for
indulging my questions.

Jonathan