submodule: refuse lookup in bare repositories

While it is technically possible to look up submodules inside of a
bare repository by reading the submodule configuration of a specific
commit, we do not offer this functionality right now. As such, calling
both `git_submodule_lookup` and `git_submodule_foreach` should error out
early when these functions encounter a bare repository. While
`git_submodule_lookup` already does return an error due to not being
able to parse the configuration, `git_submodule_foreach` simply returns
success and never invokes the callback function.

Fix the issue by having both functions check whether the repository is
bare and returning an error in that case.

9 files changed, 7 insertions, 0 deletions

diff --git a/tests/resources/submodules.git/objects/26/a3b32a9b7d97486c5557f5902e8ac94638145e b/tests/resources/submodules.git/objects/26/a3b32a9b7d97486c5557f5902e8ac94638145e
new file mode 100644
index 000000000..2c3c2cb61
--- /dev/null
+++ b/tests/resources/submodules.git/objects/26/a3b32a9b7d97486c5557f5902e8ac94638145e
@@ -0,0 +1,2 @@
+x
%�=
+�0F]�)�0�"�I�*�|��-t{?�2�ilV8���$���m��v��k�k*FDA�=(=|=6�	�DAv=��A}�&'�O�$=
\ No newline at end of file
diff --git a/tests/resources/submodules.git/objects/78/308c9251cf4eee8b25a76c7d2790c73d797357 b/tests/resources/submodules.git/objects/78/308c9251cf4eee8b25a76c7d2790c73d797357
new file mode 100644
index 000000000..c85fb5512
--- /dev/null
+++ b/tests/resources/submodules.git/objects/78/308c9251cf4eee8b25a76c7d2790c73d797357
diff --git a/tests/resources/submodules.git/objects/97/896810b3210244a62a82458b8e0819ecfc6850 b/tests/resources/submodules.git/objects/97/896810b3210244a62a82458b8e0819ecfc6850
new file mode 100644
index 000000000..1c8dbdf9f
--- /dev/null
+++ b/tests/resources/submodules.git/objects/97/896810b3210244a62a82458b8e0819ecfc6850
@@ -0,0 +1,3 @@
+x
��[
+�0E��*fʤS�	��K�����4ݿw�ׅ�9p�2MC�F�P@���u.�.�p�!�OY�diYU�'̕8X�bPn���6
+ħԞ��1[q��}0q���c[W�#�1f��R:���SZ�+Y��+{�td�lv����Om��u�_�}�5�i���`	K�
\ No newline at end of file
diff --git a/tests/resources/submodules.git/objects/b6/0fd986699ba4e9e68bea07cf8e793f323ef888 b/tests/resources/submodules.git/objects/b6/0fd986699ba4e9e68bea07cf8e793f323ef888
new file mode 100644
index 000000000..3d78bd6be
--- /dev/null
+++ b/tests/resources/submodules.git/objects/b6/0fd986699ba4e9e68bea07cf8e793f323ef888
diff --git a/tests/resources/submodules.git/objects/d5/f7fc3f74f7dec08280f370a975b112e8f60818 b/tests/resources/submodules.git/objects/d5/f7fc3f74f7dec08280f370a975b112e8f60818
new file mode 100644
index 000000000..6e0b49e86
--- /dev/null
+++ b/tests/resources/submodules.git/objects/d5/f7fc3f74f7dec08280f370a975b112e8f60818
diff --git a/tests/resources/submodules.git/objects/e3/50052cc767cd1fcb37e84e9a89e701925be4ae b/tests/resources/submodules.git/objects/e3/50052cc767cd1fcb37e84e9a89e701925be4ae
new file mode 100644
index 000000000..082a58941
--- /dev/null
+++ b/tests/resources/submodules.git/objects/e3/50052cc767cd1fcb37e84e9a89e701925be4ae
diff --git a/tests/resources/submodules.git/objects/info/packs b/tests/resources/submodules.git/objects/info/packs
new file mode 100644
index 000000000..0785ef698
--- /dev/null
+++ b/tests/resources/submodules.git/objects/info/packs
@@ -0,0 +1,2 @@
+P pack-b69d04bb39ac274669e2184e45bd90015d02ef5b.pack
+
diff --git a/tests/resources/submodules.git/objects/pack/pack-b69d04bb39ac274669e2184e45bd90015d02ef5b.idx b/tests/resources/submodules.git/objects/pack/pack-b69d04bb39ac274669e2184e45bd90015d02ef5b.idx
new file mode 100644
index 000000000..810fc3181
--- /dev/null
+++ b/tests/resources/submodules.git/objects/pack/pack-b69d04bb39ac274669e2184e45bd90015d02ef5b.idx
diff --git a/tests/resources/submodules.git/objects/pack/pack-b69d04bb39ac274669e2184e45bd90015d02ef5b.pack b/tests/resources/submodules.git/objects/pack/pack-b69d04bb39ac274669e2184e45bd90015d02ef5b.pack
new file mode 100644
index 000000000..c25c4a73f
--- /dev/null
+++ b/tests/resources/submodules.git/objects/pack/pack-b69d04bb39ac274669e2184e45bd90015d02ef5b.pack