Re: [PATCH v2] clone: use submodules.recurse option for automatically clone submodules

From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: Junio C Hamano <gitster@pobox.com>
Cc: Markus Klein via GitGitGadget <gitgitgadget@gmail.com>,
	git@vger.kernel.org, Markus Klein <masmiseim@gmx.de>
Subject: Re: [PATCH v2] clone: use submodules.recurse option for automatically clone submodules
Date: Fri, 7 Feb 2020 16:45:42 +0100 (CET)	[thread overview]
Message-ID: <nycvar.QRO.7.76.6.2002071621160.3718@tvgsbejvaqbjf.bet> (raw)
In-Reply-To: <xmqq1rr7fsh3.fsf@gitster-ct.c.googlers.com>

Hi Junio,

On Thu, 6 Feb 2020, Junio C Hamano wrote:

> "Markus Klein via GitGitGadget" <gitgitgadget@gmail.com> writes:
>
> > +static int git_clone_config(const char *var, const char *value, void *cb)
> > +{
> > +	if (!strcmp(var, "submodule.recurse") && git_config_bool(var, value)) {
> > +		string_list_append(&option_recurse_submodules, "true");
> > +		return 0;
>
> The breakage of this is not apparent, but this is misleading.  If
> submodule.recurse is set to a value that git_config_bool() would say
> "false", the if statement is skipped, and you end up calling
> git_default_config() with "submodule.recurse", even though you are
> supposed to have already dealt with the setting.
>
> 	if (!strcmp(var, "submodule.recurse")) {
> 		if (git_config_bool(var, value))
> 			...
> 		return 0; /* done with the variable either way */
> 	}
>
> is more appropriate.

Good catch, and I think you will have to do even more: in the "else" case,
it is possible that the user overrode a `submodule.recurse` from the
system config in their user-wide config, so we must _undo_ the
`string_list_append().

Further, it is probably not a good idea to append "true" _twice_ if
multiple configs in the chain specify `submodule.recurse = true`.

> I still do not know what this code is trying to do by appending "true"
> as many times as submodule.recurse appears in the configuration file(s),
> though.
>
> When given from the command line, i.e.
>
> 	git clone --no-recurse-submodules ...
> 	git clone --recurse-submodules    ...
> 	git clone --recurse-submodules=<something> ...
>
> recurse_submodules_cb() reacts to them by
>
>  (1) clearing what have been accumulated so far,
>  (2) appending the match-all "." pathspec, and
>  (3) appending the <something> string
>
> to option_recurse_submodules string list.  But given that
> submodule.recurse is not (and will not be without an involved
> transition plan) a pathspec but merely a boolean, I would think
> appending hardcoded string constant "true" makes little sense.
> After sorting the list, these values become values of the
> submodule.active configuration variable whose values are pathspec
> elements in cmd_clone(); see the part of the code before it makes a
> call to init_db().

Indeed, I think I even pointed out that "true" is not an appropriate value
to use here: https://github.com/git/git/pull/695/#discussion_r367866708

Ciao,
Dscho