Re: git submodule should honor "-c credential.helper" command line argument

[Jeff King <peff@peff.net>]

On Thu, Feb 18, 2016 at 11:29:09PM -0800, Jacob Keller wrote:

> I would prefer to either.. blacklist stuff like core.worktree, or
> whitelist a bunch of stuff that makes sense. In this case though, I
> would prefer to have an explicit test of credential.helper, but I
> don't know if any of our tests actually have a solid test case for
> "credential.helper was used in a clone. There may not be test
> infrastructure for this though, so your test might work well enough.

To trigger a credential fetch in actual use, you have to clone over
http. See the credential tests in t5550, for example.

> As for how to whitelist config to share with the submodule I am really
> not 100% sure, since we just clear GIT_CONFIG_PARAMETERS, and I think
> we'd need a specialized variant of clear_local_git_env_vars specific
> to submodule then.

Yeah, you'll have to parse, which is pretty painful. In C, you'd do
something like:

  int submodule_config_ok(const char *var)
  {
	if (starts_with(var, "credential."))
		return 1;
	return 0;
  }

  int filter_submodule_config(const char *var, const char *value, void *data)
  {
	struct strbuf *out = data;
	if (submodule_config_ok(var)) {
		if (out->len)
			strbuf_addch(out, ' ');
		/* these actually probably need quoted all as * one string */
		sq_quote_buf(out, var);
		sq_quote_buf(out, "=");
		sq_quote_buf(out, value);
	}
	return 0;
  }

and then call it like:

  struct strbuf filtered_config = STRBUF_INIT;
  git_config_from_parameters(filter_submodule_config, &filtered_config);
  argv_array_pushf(&child_process.env, "%s=%s",
                   CONFIG_DATA_ENVIRONMENT, filtered_config.buf);

but right now git-submodule.sh is all in shell. You'd probably need a
special helper from git-submodule--helper, though it might simply make
sense to put this off until the submodule code is fully ported to C.

-Peff