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> On Fri, Nov 04 2022, Glen Choo wrote:
>
>> Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:
>>
>>> 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...
>>
>> If we _really_ wanted to keep the check, an alternative might be to
>> teach the subcommand parser about SUPPORT_SUPER_PREFIX. But frankly, I
>> think this SUPPORT_SUPER_PREFIX check is far more trouble than it's
>> worth, and I wouldn't want you to spend your time trying to find ways to
>> keep it only for it to be dropped altogether.
>>
>> Here's a snippet from the cover letter I'm working on, which will
>> hopefully convince you that we don't need to worry about this any more.
>>
>> ----- >8 --------- >8 --------- >8 --------- >8 --------- >8 ----
>>
>> When we introduced the internal-only "--super-prefix" in 74866d7579 (git: make
>> super-prefix option, 2016-10-07), we specified that commands must prefix paths
>> by it, and pathspecs must be parsed relative to it. That commit also includes
>> safeguards to ensure that "--super-prefix" is used correctly, namely:
>>
>> - Only commands marked SUPPORT_SUPER_PREFIX can be invoked with "--super-prefix".
>> - The super prefix is propagated via the GIT_INTERNAL_SUPER_PREFIX env var, so a
>> non-SUPPORT_SUPER_PREFIX command cannot be invoked by a SUPPORT_SUPER_PREFIX
>> one.
>>
>> However, its use is inconsistent, which is a strong reason to consider using
>> better-scoped flags instead. For example..
>>
>> - Of the 4 commands that are SUPPORT_SUPER_PREFIX, only "read-tree" and
>> "submodule--helper" do anything useful with it. "fsmonitor--daemon" has it
>> to avoid the SUPPORT_SUPER_PREFIX warning [1]. "checkout--worker" doesn't have
>> a documented reason, but since it can be invoked by "read-tree", it's
>> presumably also a workaround.
>> - "read-tree" and "submodule--helper" use different values for the super prefix;
>> "read-tree" passes the path from the root of the superproject's tree to the
>> submodule's gitlink, while "submodule--helper" passes the relative path of the
>> original CWD to the submodule.
>> - "submodule--helper" doesn't use "--super-prefix" to parse pathspecs, only to
>> display paths.
>>
>> This series fixes replaces "--super-prefix" with such better-scoped flags, and
>> fixes some bugs resulting from the SUPPORT_SUPER_PREFIX check.
>>
>> [1] 53fcfbc84f (fsmonitor--daemon: allow --super-prefix argument, 2022-05-26)
>>
>> ----- >8 --------- >8 --------- >8 --------- >8 --------- >8 ----
>>
>> I figured out all the details, but it would look something like:
>>
>> - Add an internal-only "--tree-super-prefix" flag to "git read-tree",
>> which sets a global variable that is read from unpack-trees.c.
>> - Add an internal-only "--wt-super-prefix" flag to "git
>> submodule--helper", which sets a global variable that is read from
>> submodule.c. Unlike "--super-prefix", this won't be gated behind a
>> SUPPORT_SUPER_PREFIX for each subcommand, since AFAICT, every
>> subcommand is using this "--wt-super-prefix" correctly, so we can just
>> make sure that new subcommands do too.
>> - Remove the global "--super-prefix", the corresponding env var and
>> SUPPORT_SUPER_PREFIX.
> So for the "submodule as a built-in" I didn't want to take it hostage to
> that
Ævar Arnfjörð Bjarmason
