Re: [PATCH v6 0/6] recursively grep across submodules

[Jeff King <peff@peff.net>]

On Thu, Dec 01, 2016 at 09:45:47AM -0800, Brandon Williams wrote:

> Yeah I was trying to think through these scenarios myself last night.
> And like you found it seemed alright to let the child process deal with
> the .git file/dir as long as once actually exists at that path.  If one
> didn't then there would be the possibility that we ended up back at the
> superproject, which would result in an infinite loop.  And yeah if the
> .git file doesn't resolve to anything sensible then the user probably
> mangled their repository somehow anyways.

I hadn't considered the infinite loop. I thought the worst case is that
we might just generate bogus results by going back to the superproject.
But of course there is nothing to stop it from just recursing again.

However, it looks like there is a circuit-breaker; we end up back in the
superproject, but inside a subdirectory, which causes --super-prefix to
complain.

You can test it with just:

  rm submodule/.git
  mkdir submodule/.git

which says:

  fatal: can't use --super-prefix from a subdirectory
  fatal: process for submodule 'foo' failed with exit code: 128

It might be worth including a test to make sure that behavior remains.
I think it's more of an emergent behavior than something planned. :)

-Peff