Re: [PATCH 05/10] submodule--helper: add is_active command

> There are a lot of places where an explicit check for
> submodule."<name>".url is done to see if a submodule exists.  In order
> to more easily facilitate the use of the submodule.active config option
> to indicate active submodules, add a helper which can be used to query
> if a submodule is active or not.
>
> Signed-off-by: Brandon Williams <bmwill@google.com>
> ---
>  builtin/submodule--helper.c    | 11 ++++++++
>  t/t7413-submodule-is-active.sh | 63 ++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 74 insertions(+)
>  create mode 100755 t/t7413-submodule-is-active.sh
>
> diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
> index df0d9c166..dac02604d 100644
> --- a/builtin/submodule--helper.c
> +++ b/builtin/submodule--helper.c
> @@ -1128,6 +1128,16 @@ static int absorb_git_dirs(int argc, const char **argv, const char *prefix)
>         return 0;
>  }
>
> +static int is_active(int argc, const char **argv, const char *prefix)
> +{
> +       if (argc != 2)
> +               die("submodule--helper is-active takes exactly 1 arguments");
> +
> +       gitmodules_config();
> +
> +       return !is_submodule_initialized(argv[1]);
> +}
> +
>  #define SUPPORT_SUPER_PREFIX (1<<0)
>
>  struct cmd_struct {
> @@ -1147,6 +1157,7 @@ static struct cmd_struct commands[] = {
>         {"init", module_init, 0},
>         {"remote-branch", resolve_remote_submodule_branch, 0},
>         {"absorb-git-dirs", absorb_git_dirs, SUPPORT_SUPER_PREFIX},
> +       {"is-active", is_active, 0},
>  };
>
>  int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
> diff --git a/t/t7413-submodule-is-active.sh b/t/t7413-submodule-is-active.sh
> new file mode 100755
> index 000000000..683487020
> --- /dev/null
> +++ b/t/t7413-submodule-is-active.sh
> @@ -0,0 +1,63 @@
> +#!/bin/sh
> +
> +test_description='Test submodule--helper is-active
> +
> +This test verifies that `git submodue--helper is-active` correclty identifies
> +submodules which are "active" and interesting to the user.
> +'
> +
> +. ./test-lib.sh
> +
> +test_expect_success 'setup' '
> +       git init sub &&
> +       test_commit -C sub initial &&
> +       git init super &&
> +       test_commit -C super initial &&
> +       git -C super submodule add ../sub sub1 &&
> +       git -C super submodule add ../sub sub2 &&
> +       git -C super commit -a -m "add 2 submodules at sub{1,2}"
> +'
> +
> +test_expect_success 'is-active works with urls' '
> +       git -C super submodule--helper is-active sub1 &&
> +       git -C super submodule--helper is-active sub2 &&
> +
> +       git -C super config --unset submodule.sub1.URL &&
> +       test_must_fail git -C super submodule--helper is-active sub1 &&
> +       git -C super config submodule.sub1.URL ../sub &&
> +       git -C super submodule--helper is-active sub1
> +'
> +
> +test_expect_success 'is-active works with basic submodule.active config' '
> +       git -C super config --add submodule.active "." &&
> +       git -C super config --unset submodule.sub1.URL &&
> +       git -C super config --unset submodule.sub2.URL &&