use git clone --branch instead of --no-checkout

git submodule update does not cause an actual checkout if HEAD matches
the recorded submodule sha1 even if it was not actually checked out.

it would be possible to work around this by calling git checkout HEAD in
each submodule if no files are checked out, but that seems hacky.

instead, just make the module cloning already check out the desired
branch. this produces checkouts that are within a few commits of the
final sha1, so isn't too bad.

Change-Id: I435c1a2e24f39fd8c0d65f0d90df0216715668b7

1 files changed, 4 insertions, 3 deletions

diff --git a/init-repository b/init-repository
index 9a08406e..581d108e 100755
--- a/init-repository
+++ b/init-repository
@@ -383,7 +383,7 @@ sub git_clone_all_submodules
     }
 
     foreach my $module (@modules) {
-        $self->git_clone_one_submodule($subdirs{$module}, $subbases{$module});
+        $self->git_clone_one_submodule($subdirs{$module}, $subbases{$module}, $subbranches{$module});
     }
 
     if ($co_branch) {
@@ -440,7 +440,7 @@ sub git_add_remotes
 
 sub git_clone_one_submodule
 {
-    my ($self, $submodule, $repo_basename) = @_;
+    my ($self, $submodule, $repo_basename, $branch) = @_;
 
     my $alternates            = $self->{ 'alternates'        };
     my $mirror_url            = $self->{ 'mirror-url'        };
@@ -476,7 +476,8 @@ sub git_clone_one_submodule
 
     my $do_clone = (! -e "$submodule/.git");
     if ($do_clone) {
-        $self->exe('git', 'clone', '--no-checkout', @reference_args,
+        push @reference_args, '--branch', $branch if ($branch);
+        $self->exe('git', 'clone', @reference_args,
                    ($mirror ? $mirror : $url), $submodule);
     }