[PATCH] submodule init: fail gracefully with a missing .gitmodules file

[PATCH] submodule init: fail gracefully with a missing .gitmodules file

[Stefan Beller]

When there is no .gitmodules file availabe to initialize a submodule
from, `submodule_from_path` just returns NULL. We need to check for
that and abort gracefully. When `submodule init` was implemented in shell,
a missing .gitmodules file would result in an error message

    No url found for submodule path '%s' in .gitmodules

While that is technically true, I think we can broaden the error message
and just say there is no section for the submodule in the .gitmodules file.

Signed-off-by: Stefan Beller <sbeller@google.com>
---

 This goes on top of sb/submodule-init (I added the base-commit
 below, just in case anyone uses that feature already. Though I did
 that manually :)
 
 Thanks,
 Stefan

 builtin/submodule--helper.c | 10 +++++++---
 t/t7400-submodule-basic.sh  |  8 ++++++++
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index b6d4f27..af5406e 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -314,13 +314,17 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
 	/* Only loads from .gitmodules, no overlay with .git/config */
 	gitmodules_config();
 
-	sub = submodule_from_path(null_sha1, path);
-
 	if (prefix) {
 		strbuf_addf(&sb, "%s%s", prefix, path);
 		displaypath = strbuf_detach(&sb, NULL);
 	} else
-		displaypath = xstrdup(sub->path);
+		displaypath = xstrdup(path);
+
+	sub = submodule_from_path(null_sha1, path);
+
+	if (!sub)
+		die(_("No section found for submodule path '%s' in .gitmodules"),
+			displaypath);
 
 	/*
 	 * Copy url setting when it is not set yet.
diff --git a/t/t7400-submodule-basic.sh b/t/t7400-submodule-basic.sh
index f99f674..f2b3519 100755
--- a/t/t7400-submodule-basic.sh
+++ b/t/t7400-submodule-basic.sh
@@ -18,6 +18,14 @@ test_expect_success 'setup - initial commit' '
 	git branch initial
 '
 
+test_expect_success 'sane abort on missing .gitmodules file' '
+	test_when_finished "git update-index --remove sub" &&
+	git update-index --add --cacheinfo 160000,$(git rev-parse HEAD),sub &&
+	# missing the .gitmodules file here
+	test_must_fail git submodule init 2>actual &&
+	test_i18ngrep "No section found for submodule path" actual
+'
+
 test_expect_success 'configuration parsing' '
 	test_when_finished "rm -f .gitmodules" &&
 	cat >.gitmodules <<-\EOF &&
-- 
2.8.0.26.g3604242.dirty

base-commit: 3604242f080a813d6f20a7394def422d1e55b30e

Re: [PATCH] submodule init: fail gracefully with a missing .gitmodules file

[Stefan Beller]

On Thu, Apr 28, 2016 at 11:28 AM, Stefan Beller <sbeller@google.com> wrote:
> When there is no .gitmodules file availabe to initialize a submodule
> from, `submodule_from_path` just returns NULL. We need to check for
> that and abort gracefully. When `submodule init` was implemented in shell,
> a missing .gitmodules file would result in an error message
>
>     No url found for submodule path '%s' in .gitmodules
>
> While that is technically true, I think we can broaden the error message
> and just say there is no section for the submodule in the .gitmodules file.

Actually I am not so sure any more about this part. In a resend I will use
the old error message again.

This fix is also required for `submodule--helper update-clone`.

>
> Signed-off-by: Stefan Beller <sbeller@google.com>
> ---
>
>  This goes on top of sb/submodule-init (I added the base-commit
>  below, just in case anyone uses that feature already. Though I did
>  that manually :)
>
>  Thanks,
>  Stefan
>
>  builtin/submodule--helper.c | 10 +++++++---
>  t/t7400-submodule-basic.sh  |  8 ++++++++
>  2 files changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
> index b6d4f27..af5406e 100644
> --- a/builtin/submodule--helper.c
> +++ b/builtin/submodule--helper.c
> @@ -314,13 +314,17 @@ static void init_submodule(const char *path, const char *prefix, int quiet)
>         /* Only loads from .gitmodules, no overlay with .git/config */
>         gitmodules_config();
>
> -       sub = submodule_from_path(null_sha1, path);
> -
>         if (prefix) {
>                 strbuf_addf(&sb, "%s%s", prefix, path);
>                 displaypath = strbuf_detach(&sb, NULL);
>         } else
> -               displaypath = xstrdup(sub->path);
> +               displaypath = xstrdup(path);
> +
> +       sub = submodule_from_path(null_sha1, path);
> +
> +       if (!sub)
> +               die(_("No section found for submodule path '%s' in .gitmodules"),
> +                       displaypath);
>
>         /*
>          * Copy url setting when it is not set yet.
> diff --git a/t/t7400-submodule-basic.sh b/t/t7400-submodule-basic.sh
> index f99f674..f2b3519 100755
> --- a/t/t7400-submodule-basic.sh
> +++ b/t/t7400-submodule-basic.sh
> @@ -18,6 +18,14 @@ test_expect_success 'setup - initial commit' '
>         git branch initial
>  '
>
> +test_expect_success 'sane abort on missing .gitmodules file' '
> +       test_when_finished "git update-index --remove sub" &&
> +       git update-index --add --cacheinfo 160000,$(git rev-parse HEAD),sub &&
> +       # missing the .gitmodules file here
> +       test_must_fail git submodule init 2>actual &&
> +       test_i18ngrep "No section found for submodule path" actual
> +'
> +
>  test_expect_success 'configuration parsing' '
>         test_when_finished "rm -f .gitmodules" &&
>         cat >.gitmodules <<-\EOF &&
> --
> 2.8.0.26.g3604242.dirty
>
> base-commit: 3604242f080a813d6f20a7394def422d1e55b30e