Merge branch '21636-deleting-source-project-with-existing-fork-closes-all-related-merge-requests' into 'master'

Deleting source project with existing fork link should closes all
related merge requests, and does not render `invalid` template for merge
requests with deleted source project.
The merge request without source project can be edited but can't be reopened.

Closes #21636 

See merge request !6177

2 files changed, 96 insertions, 0 deletions

diff --git a/spec/controllers/projects_controller_spec.rb b/spec/controllers/projects_controller_spec.rb
index ffe0641ddd7..b0f740f48f7 100644
--- a/spec/controllers/projects_controller_spec.rb
+++ b/spec/controllers/projects_controller_spec.rb
@@ -181,6 +181,25 @@ describe ProjectsController do
       expect(response).to have_http_status(302)
       expect(response).to redirect_to(dashboard_projects_path)
     end
+
+    context "when the project is forked" do
+      let(:project)      { create(:project) }
+      let(:fork_project) { create(:project, forked_from_project: project) }
+      let(:merge_request) do
+        create(:merge_request,
+          source_project: fork_project,
+          target_project: project)
+      end
+
+      it "closes all related merge requests" do
+        project.merge_requests << merge_request
+        sign_in(admin)
+
+        delete :destroy, namespace_id: fork_project.namespace.path, id: fork_project.path
+
+        expect(merge_request.reload.state).to eq('closed')
+      end
+    end
   end
 
   describe "POST #toggle_star" do
diff --git a/spec/models/merge_request_spec.rb b/spec/models/merge_request_spec.rb
index 5bf3b8e609e..3b815ded2d3 100644
--- a/spec/models/merge_request_spec.rb
+++ b/spec/models/merge_request_spec.rb
@@ -1038,4 +1038,81 @@ describe MergeRequest, models: true do
       end
     end
   end
+
+  describe '#closed_without_source_project?' do
+    let(:project)      { create(:project) }
+    let(:user)         { create(:user) }
+    let(:fork_project) { create(:project, forked_from_project: project, namespace: user.namespace) }
+    let(:destroy_service) { Projects::DestroyService.new(fork_project, user) }
+
+    context 'when the merge request is closed' do
+      let(:closed_merge_request) do
+        create(:closed_merge_request,
+          source_project: fork_project,
+          target_project: project)
+      end
+
+      it 'returns false if the source project exists' do
+        expect(closed_merge_request.closed_without_source_project?).to be_falsey
+      end
+
+      it 'returns true if the source project does not exist' do
+        destroy_service.execute
+        closed_merge_request.reload
+
+        expect(closed_merge_request.closed_without_source_project?).to be_truthy
+      end
+    end
+
+    context 'when the merge request is open' do
+      it 'returns false' do
+        expect(subject.closed_without_source_project?).to be_falsey
+      end
+    end
+  end
+
+  describe '#reopenable?' do
+    context 'when the merge request is closed' do
+      it 'returns true' do
+        subject.close
+
+        expect(subject.reopenable?).to be_truthy
+      end
+
+      context 'forked project' do
+        let(:project)      { create(:project) }
+        let(:user)         { create(:user) }
+        let(:fork_project) { create(:project, forked_from_project: project, namespace: user.namespace) }
+        let(:merge_request) do
+          create(:closed_merge_request,
+            source_project: fork_project,
+            target_project: project)
+        end
+
+        it 'returns false if unforked' do
+          Projects::UnlinkForkService.new(fork_project, user).execute
+
+          expect(merge_request.reload.reopenable?).to be_falsey
+        end
+
+        it 'returns false if the source project is deleted' do
+          Projects::DestroyService.new(fork_project, user).execute
+
+          expect(merge_request.reload.reopenable?).to be_falsey
+        end
+
+        it 'returns false if the merge request is merged' do
+          merge_request.update_attributes(state: 'merged')
+
+          expect(merge_request.reload.reopenable?).to be_falsey
+        end
+      end
+    end
+
+    context 'when the merge request is opened' do
+      it 'returns false' do
+        expect(subject.reopenable?).to be_falsey
+      end
+    end
+  end
 end