Doc: document push.recurseSubmodules=only

Git learned pushing submodules without pushing the superproject by
the user specifying --recurse-submodules=only through 6c656c3fe4
("submodules: add RECURSE_SUBMODULES_ONLY value", 2016-12-20) and
225e8bf778 ("push: add option to push only submodules", 2016-12-20).
For users who use this feature regularly, it is desirable to have an
equivalent configuration.

It turns out that such a configuration (push.recurseSubmodules=only) is
already supported, even though it is neither documented nor mentioned
in the commit messages, due to the way the --recurse-submodules=only
feature was implemented (a function used to parse --recurse-submodules
was updated to support "only", but that same function is used to parse
push.recurseSubmodules too). What is left is to document it and test it,
which is what this commit does.

There is a possible point of confusion when recursing into a submodule
that itself has the push.recurseSubmodules=only configuration, because
if a repository has only its submodules pushed and not itself, its
superproject can never be pushed. Therefore, treat such configurations
as being "on-demand", and print a warning message.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>

1 files changed, 50 insertions, 0 deletions

diff --git a/t/t5531-deep-submodule-push.sh b/t/t5531-deep-submodule-push.sh
index 3f58b515ce..302e4cbdba 100755
--- a/t/t5531-deep-submodule-push.sh
+++ b/t/t5531-deep-submodule-push.sh
@@ -512,6 +512,56 @@ test_expect_success 'push only unpushed submodules recursively' '
 	test_cmp expected_pub actual_pub
 '
 
+setup_subsub () {
+	git init upstream &&
+	git init upstream/sub &&
+	git init upstream/sub/deepsub &&
+	test_commit -C upstream/sub/deepsub innermost &&
+	git -C upstream/sub submodule add ./deepsub deepsub &&
+	git -C upstream/sub commit -m middle &&
+	git -C upstream submodule add ./sub sub &&
+	git -C upstream commit -m outermost &&
+
+	git -c protocol.file.allow=always clone --recurse-submodules upstream downstream &&
+	git -C downstream/sub/deepsub checkout -b downstream-branch &&
+	git -C downstream/sub checkout -b downstream-branch &&
+	git -C downstream checkout -b downstream-branch
+}
+
+new_downstream_commits () {
+	test_commit -C downstream/sub/deepsub new-innermost &&
+	git -C downstream/sub add deepsub &&
+	git -C downstream/sub commit -m new-middle &&
+	git -C downstream add sub &&
+	git -C downstream commit -m new-outermost
+}
+
+test_expect_success 'push with push.recurseSubmodules=only on superproject' '
+	test_when_finished rm -rf upstream downstream &&
+	setup_subsub &&
+	new_downstream_commits &&
+	git -C downstream config push.recurseSubmodules only &&
+	git -C downstream push origin downstream-branch &&
+
+	test_must_fail git -C upstream rev-parse refs/heads/downstream-branch &&
+	git -C upstream/sub rev-parse refs/heads/downstream-branch &&
+	test_must_fail git -C upstream/sub/deepsub rev-parse refs/heads/downstream-branch
+'
+
+test_expect_success 'push with push.recurseSubmodules=only on superproject and top-level submodule' '
+	test_when_finished rm -rf upstream downstream &&
+	setup_subsub &&
+	new_downstream_commits &&
+	git -C downstream config push.recurseSubmodules only &&
+	git -C downstream/sub config push.recurseSubmodules only &&
+	git -C downstream push origin downstream-branch 2> err &&
+
+	test_must_fail git -C upstream rev-parse refs/heads/downstream-branch &&
+	git -C upstream/sub rev-parse refs/heads/downstream-branch &&
+	git -C upstream/sub/deepsub rev-parse refs/heads/downstream-branch &&
+	grep "recursing into submodule with push.recurseSubmodules=only; using on-demand instead" err
+'
+
 test_expect_success 'push propagating the remotes name to a submodule' '
 	git -C work remote add origin ../pub.git &&
 	git -C work remote add pub ../pub.git &&