Re: [PATCH v4] config: add conditional include

[Jeff King <peff@peff.net>]

On Sat, Jul 16, 2016 at 03:30:45PM +0200, Johannes Schindelin wrote:

> > >> +     ; include if $GIT_DIR is /path/to/foo/.git
> > >> +     [include "gitdir:/path/to/foo/.git"]
> > >> +             path = /path/to/foo.inc
> > >
> > > I find this way to specify a conditional unintuitive. Reading
> > > "gitdir:/path/to/foo/.git" suggests to me that the Git dir is *re-set*,
> > > not that this is a condition.
> > 
> > Well.. to me it's no different than [remote "foo"] to apply stuff to "foo".
> 
> Except that "include" is an imperative and "remote" is not.

In the very original version of config includes, I had planned out:

  [include-if "...some condition..."]
  path = ...

Later, since "[include ...]" had no other meaning, I think it got
shortened in discussion. But it would be easy to accept include-if (or
even accept either, for maximum confusion :) ).

> Quite frankly, this conditional business scares me. If you introduce it
> for [include], users will want it for every config setting. And the
> current syntax is just not up to, say, making user.name conditional on
> anything.

They already have it for every config setting with this. The reason to
add it to [include] and not as a general syntax is that you can put
user.name into your included file, and then conditionally include it.

That is not as nice as "if this then that" in a single file, but it is
backwards compatible with the existing syntax, and is probably fine in
practice. Each included file becomes a "profile" of multiple settings
that you apply.

> As an alternative solution to your problem, you could of course avoid all
> conditional includes. Simply by adding the include.path settings
> explicitly to the configs that require them. Now, that would make reasoning
> and trouble-shooting simple, wouldn't it?
> 
> And the most beautiful aspect of it: no patch needed.

And you can just "cat" the included files directly into your
.git/config. We don't even need include.path. Or ~/.gitconfig, for that
matter. But sometimes dynamic things are convenient.

-Peff