Re: [PATCH v4 05/10] userdiff: add and use for_each_userdiff_driver()

On Thu, Mar 25, 2021 at 12:05:09AM +0100, Ævar Arnfjörð Bjarmason wrote:

quoted

  As an aside, it feels like this is something we ought to be able to
  ask git-config about, rather than having a test-helper. This is
  basically "baked-in" config, and if we represented it as such, and
  parsed it into a struct just like regular config, then probably "git
  config --list --source" could be used to find it (and differentiate it
  from user-provided config). Possible downsides:

    1. Would people find it confusing that "git config --list" suddenly
       gets way bigger? Maybe we'd want an "--include-baked-in" option
       or something.

    2. Is the cost of parsing the config measurably bad? Obviously a
       user could provide the same content and we'd have to parse it,
       but there's a lot more rules here than most users would probably
       provide.

Also:

 3. Only the PATTERNS() macro translates as-is to config syntax. We
    don't have a way to do what IPATTERN() does in the config syntax
    currently.

    We could add a ifuncname and xifuncname or whatever for it I guess,
    but currently the ICASE behavior in the C code is magic.

Good point. IMHO that is something we should consider fixing
independently. It was a mistake to add builtins that couldn't be
replicated via the config (though I notice it happened quite a while
ago, and nobody seems to have cared, so perhaps it isn't that
important).

I have also wondered if we should just ship a file which could be
installed as /etc/gitconfig.filetypes and include it the stock
/etc/gitconfig. That is effectively the same as "baked in", but
hopefully makes it more clear to users how they can modify things.  But
all of that is somewhat orthogonal to what you're doing here.

-Peff