submodule_links: Handle in-repository submodule urls

Sometimes it is useful to store submodules in the same repository which
contains links to them.  Make the UI support this.

See
https://github.com/twosigma/git-meta/wiki/The-Omega-Repo
for information about this strategy

Signed-off-by: David Turner <novalis@novalis.org>

app/helpers/submodule_helper.rb

@@ -7,6 +7,10 @@ module SubmoduleHelper
   def submodule_links(submodule_item, ref = nil, repository = @repository)
     url = repository.submodule_url_for(ref, submodule_item.path)
 
+    if url == '.' || url == './'
+      url = File.join(Gitlab.config.gitlab.url, @project.full_path)
+    end
+
     if url =~ /([^\/:]+)\/([^\/]+(?:\.git)?)\Z/
       namespace, project = $1, $2
       project.sub!(/\.git\z/, '')

changelogs/unreleased/omega-submodules.yml

@@ -0,0 +1,4 @@
+---
+title: 'Repository browser: handle in-repository submodule urls'
+merge_request:
+author: David Turner

spec/helpers/submodule_helper_spec.rb

@@ -81,6 +81,19 @@ describe SubmoduleHelper do
       end
     end
 
+    context 'in-repository submodule' do
+      let(:group) { create(:group, name: "Master Project", path: "master-project") }
+      let(:project) { create(:empty_project, group: group) }
+      before do
+        self.instance_variable_set(:@project, project)
+      end
+
+      it 'in-repository' do
+        stub_url('./')
+        expect(submodule_links(submodule_item)).to eq(["/master-project/#{project.path}", "/master-project/#{project.path}/tree/hash"])
+      end
+    end
+
     context 'submodule on gitlab.com' do
       it 'detects ssh' do
         stub_url('git@gitlab.com:gitlab-org/gitlab-ce.git')