Allow collaboration with forks through the API

These APIs are used by the web IDE.

They need to be on par with git & web access, allowing edits from
maintainers to forks with merge requests that allow access.

1 files changed, 52 insertions, 2 deletions

diff --git a/spec/requests/api/commits_spec.rb b/spec/requests/api/commits_spec.rb
index 113703fac38..246947e58a8 100644
--- a/spec/requests/api/commits_spec.rb
+++ b/spec/requests/api/commits_spec.rb
@@ -514,6 +514,38 @@ describe API::Commits do
         expect(response).to have_gitlab_http_status(400)
       end
     end
+
+    context 'when committing into a fork as a maintainer' do
+      include_context 'merge request allowing collaboration'
+
+      let(:project_id) { forked_project.id }
+
+      def push_params(branch_name)
+        {
+          branch: branch_name,
+          commit_message: 'Hello world',
+          actions: [
+            {
+              action: 'create',
+              file_path: 'foo/bar/baz.txt',
+              content: 'puts 8'
+            }
+          ]
+        }
+      end
+
+      it 'allows pushing to the source branch of the merge request' do
+        post api(url, user), push_params('feature')
+
+        expect(response).to have_gitlab_http_status(:created)
+      end
+
+      it 'denies pushing to another branch' do
+        post api(url, user), push_params('other-branch')
+
+        expect(response).to have_gitlab_http_status(:forbidden)
+      end
+    end
   end
 
   describe 'GET /projects/:id/repository/commits/:sha/refs' do
@@ -1065,11 +1097,29 @@ describe API::Commits do
         it 'returns 400 if you are not allowed to push to the target branch' do
           post api(route, current_user), branch: 'feature'
 
-          expect(response).to have_gitlab_http_status(400)
-          expect(json_response['message']).to eq('You are not allowed to push into this branch')
+          expect(response).to have_gitlab_http_status(:forbidden)
+          expect(json_response['message']).to match(/You are not allowed to push into this branch/)
         end
       end
     end
+
+    context 'when cherry picking to a fork as a maintainer' do
+      include_context 'merge request allowing collaboration'
+
+      let(:project_id) { forked_project.id }
+
+      it 'allows access from a maintainer that to the source branch' do
+        post api(route, user), branch: 'feature'
+
+        expect(response).to have_gitlab_http_status(:created)
+      end
+
+      it 'denies cherry picking to another branch' do
+        post api(route, user), branch: 'master'
+
+        expect(response).to have_gitlab_http_status(:forbidden)
+      end
+    end
   end
 
   describe 'POST /projects/:id/repository/commits/:sha/comments' do