Re: [PATCH 8/8] submodule--helper: use OPT_SUBCOMMAND() API

From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: Glen Choo <chooglen@google.com>
Cc: git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>,
	Emily Shaffer <emilyshaffer@google.com>
Subject: Re: [PATCH 8/8] submodule--helper: use OPT_SUBCOMMAND() API
Date: Fri, 04 Nov 2022 02:22:54 +0100	[thread overview]
Message-ID: <221104.86wn8bzeus.gmgdl@evledraar.gmail.com> (raw)
In-Reply-To: <kl6l7d0bobt0.fsf@chooglen-macbookpro.roam.corp.google.com>

On Thu, Nov 03 2022, Glen Choo wrote:

> Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:
> [...]
>> +	struct option options[] = {
>> +		OPT_SUBCOMMAND("clone", &fn, module_clone),
>> +		OPT_SUBCOMMAND("add", &fn, module_add),
>> +		OPT_SUBCOMMAND("update", &fn, module_update),
>> +		OPT_SUBCOMMAND("foreach", &fn, module_foreach),
>> +		OPT_SUBCOMMAND("init", &fn, module_init),
>> +		OPT_SUBCOMMAND("status", &fn, module_status),
>> +		OPT_SUBCOMMAND("sync", &fn, module_sync),
>> +		OPT_SUBCOMMAND("deinit", &fn, module_deinit),
>> +		OPT_SUBCOMMAND("summary", &fn, module_summary),
>> +		OPT_SUBCOMMAND("push-check", &fn, push_check),
>> +		OPT_SUBCOMMAND("absorbgitdirs", &fn, absorb_git_dirs),
>> +		OPT_SUBCOMMAND("set-url", &fn, module_set_url),
>> +		OPT_SUBCOMMAND("set-branch", &fn, module_set_branch),
>> +		OPT_SUBCOMMAND("create-branch", &fn, module_create_branch),
>> +		OPT_END()
>> +	};
>> +	argc = parse_options(argc, argv, prefix, options, usage, 0);
>> +	subcmd = argv[0];
>> +
>> +	if (strcmp(subcmd, "clone") && strcmp(subcmd, "update") &&
>> +	    strcmp(subcmd, "foreach") && strcmp(subcmd, "status") &&
>> +	    strcmp(subcmd, "sync") && strcmp(subcmd, "absorbgitdirs") &&
>> +	    get_super_prefix())
>> +		/*
>> +		 * xstrfmt() rather than "%s %s" to keep the translated
>> +		 * string identical to git.c's.
>> +		 */
>> +		die(_("%s doesn't support --super-prefix"),
>> +		    xstrfmt("'%s %s'", cmd, subcmd));
>
> FYI I'm preparing a series to get rid of the SUPPORT_SUPER_PREFIX checks
> in both the top level and in submodule--helper (i.e. revisiting my
> complaints from [1]), but I haven't sent it out yet because I haven't
> found the right way to motivate that change. Feel free to chime in on
> that series when it comes out.
>
> [1] https://lore.kernel.org/git/20220630221147.45689-5-chooglen@google.com/

Maybe you have different plans, but keep at the WIP re-roll of what I
have after this, I've also removed all of that.

Basically, ending up with:

	--- a/builtin.h
	+++ b/builtin.h
	@@ -224,7 +224,14 @@ int cmd_sparse_checkout(int argc, const char **argv, const char *prefix);
	 int cmd_status(int argc, const char **argv, const char *prefix);
	 int cmd_stash(int argc, const char **argv, const char *prefix);
	 int cmd_stripspace(int argc, const char **argv, const char *prefix);
	+int cmd_submodule(int argc, const char **argv, const char *prefix);
	 int cmd_submodule__helper(int argc, const char **argv, const char *prefix);
	+int cmd_submodule__helper_clone(int argc, const char **argv, const char *prefix);
	+int cmd_submodule_absorbgitdirs(int argc, const char **argv, const char *prefix);
	+int cmd_submodule_foreach(int argc, const char **argv, const char *prefix);
	+int cmd_submodule_status(int argc, const char **argv, const char *prefix);
	+int cmd_submodule_sync(int argc, const char **argv, const char *prefix);
	+int cmd_submodule_update(int argc, const char **argv, const char *prefix);
	 int cmd_switch(int argc, const char **argv, const char *prefix);
	 int cmd_symbolic_ref(int argc, const char **argv, const char *prefix);
	 int cmd_tag(int argc, const char **argv, const char *prefix);

And changes like:

	@@ -366,7 +365,7 @@ static void runcommand_in_submodule_cb(const struct cache_entry *list_item,

	                strvec_pushl(&cpr.args, "--super-prefix", NULL);
	                strvec_pushf(&cpr.args, "%s/", displaypath);
	-               strvec_pushl(&cpr.args, "submodule--helper", "foreach", "--recursive",
	+               strvec_pushl(&cpr.args, "submodule--helper-foreach", "--recursive",
	                             NULL);

	                if (info->quiet)

I.e. when we call "foreach" we dispatch to cmd_submodule_foreach(), but
when "foreach" needs to recurse it doesn't invoke a "git submodule
foreach", instead it invokes "git submodule--helper-foreach".

The reason for doing that is that we can't promote the helper to a
built-in without also leaking implementation detail that we support the
now internal-only --super-prefix in the command itself.

So this code becomes:

	@@ -3352,43 +3304,17 @@ static int module_add(int argc, const char **argv, const char *prefix)

	 int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
	 {
	-       const char *cmd = argv[0];
	-       const char *subcmd;
	        parse_opt_subcommand_fn *fn = NULL;
	        const char *const usage[] = {
	                N_("git submodule--helper <command>"),
	                NULL
	        };
	        struct option options[] = {
	-               OPT_SUBCOMMAND("clone", &fn, module_clone),
	-               OPT_SUBCOMMAND("add", &fn, module_add),
	-               OPT_SUBCOMMAND("update", &fn, module_update),
	-               OPT_SUBCOMMAND("foreach", &fn, module_foreach),
	-               OPT_SUBCOMMAND("init", &fn, module_init),
	-               OPT_SUBCOMMAND("status", &fn, module_status),
	-               OPT_SUBCOMMAND("sync", &fn, module_sync),
	-               OPT_SUBCOMMAND("deinit", &fn, module_deinit),
	-               OPT_SUBCOMMAND("summary", &fn, module_summary),
	-               OPT_SUBCOMMAND("push-check", &fn, push_check),
	-               OPT_SUBCOMMAND("absorbgitdirs", &fn, absorb_git_dirs),
	-               OPT_SUBCOMMAND("set-url", &fn, module_set_url),
	-               OPT_SUBCOMMAND("set-branch", &fn, module_set_branch),
	-               OPT_SUBCOMMAND("create-branch", &fn, module_create_branch),
	+               OPT_SUBCOMMAND("push-check", &fn, cmd_submodule_push_check),
	+               OPT_SUBCOMMAND("create-branch", &fn, cmd_submodule_create_branch),
	                OPT_END()
	        };
	        argc = parse_options(argc, argv, prefix, options, usage, 0);
	-       subcmd = argv[0];
	-
	-       if (strcmp(subcmd, "clone") && strcmp(subcmd, "update") &&
	-           strcmp(subcmd, "foreach") && strcmp(subcmd, "status") &&
	-           strcmp(subcmd, "sync") && strcmp(subcmd, "absorbgitdirs") &&
	-           get_super_prefix())
	-               /*
	-                * xstrfmt() rather than "%s %s" to keep the translated
	-                * string identical to git.c's.
	-                */
	-               die(_("%s doesn't support --super-prefix"),
	-                   xstrfmt("'%s %s'", cmd, subcmd));

	        return fn(argc, argv, prefix);
	 }

I.e. for all the "super-prefix" ones we dispatch directly (and maybe I
should just do that too for those two stragglers).

It's ugly, but it's only ugly on the inside, but if you can think of a
better way to do it...