Re: [PATCH v3 05/10] submodule: decouple url and submodule existence

> Currently the submodule.<name>.url config option is used to determine
> if a given submodule exists and is interesting to the user.  This
> however doesn't work very well because the URL is a config option for
> the scope of a repository, whereas the existence of a submodule is an
> option scoped to the working tree.
>
> In a future with worktree support for submodules, there will be multiple
> working trees, each of which may only need a subset of the submodules
> checked out.  The URL (which is where the submodule repository can be
> obtained) should not differ between different working trees.
>
> It may also be convenient for users to more easily specify groups of
> submodules they are interested in as apposed to running "git submodule
> init <path>" on each submodule they want checked out in their working
> tree.
>
> To this end two config options are introduced, submodule.active and
> submodule.<name>.active.  The submodule.active config holds a pathspec
> that specifies which submodules should exist in the working tree.  The
> submodule.<name>.active config is a boolean flag used to indicate if
> that particular submodule should exist in the working tree.
>
> Given these multiple ways to check for a submodule's existence the more
> fine-grained submodule.<name>.active option has the highest order of
> precedence followed by the pathspec check against submodule.active. To
> ensure backwards compatibility, if neither of these options are set git
> falls back to checking the submodule.<name>.url option to determine a
> submodule's existence.
>

>
> +submodule.<name>.active::
> +       Boolean value indicating if the submodule is of interest to git
> +       commands.  This config option takes precedence over the
> +       submodule.active config option.