Fix Error 500 when relative submodule resolves to a namespace that has a different name from its path

Closes #1849

CHANGELOG

@@ -1,6 +1,7 @@
 Please view this file on the master branch, on stable branches it's out of date.
 
 v 7.13.0 (unreleased)
+  - Fix Error 500 when relative submodule resolves to a namespace that has a different name from its path (Stan Hu)
   - Update maintenance documentation to explain no need to recompile asssets for omnibus installations (Stan Hu)
   - Support commenting on diffs in side-by-side mode (Stan Hu)
   - Fix JavaScript error when clicking on the comment button on a diff line that has a comment already (Stan Hu)

app/helpers/submodule_helper.rb

@@ -63,7 +63,7 @@ module SubmoduleHelper
     namespace = components.pop.gsub(/^\.\.$/, '')
 
     if namespace.empty?
-      namespace = @project.namespace.name
+      namespace = @project.namespace.path
     end
 
     [

spec/helpers/submodule_helper_spec.rb

@@ -115,7 +115,7 @@ describe SubmoduleHelper do
     end
 
     context 'submodules with relative links' do
-      let(:group) { create(:group) }
+      let(:group) { create(:group, name: "Master Project", path: "master-project") }
       let(:project) { create(:project, group: group) }
       let(:commit_id) { sample_commit[:id] }