Fix error when creating issues in scoped boards

Fix Unprocessable Entity error when creating issues in
scoped issue boards.

ee/app/services/ee/boards/issues/create_service.rb

@@ -13,14 +13,19 @@ module EE
             milestone_id = list.milestone_id || board.milestone_id
 
             options[:label_ids].concat(board.label_ids)
+            options[:weight] = board.weight if valid_weight?
+
             options.merge!(
-              weight: board.weight,
               milestone_id: milestone_id,
               # This can be removed when boards have multiple assignee support.
               # See https://gitlab.com/gitlab-org/gitlab-ee/issues/3786
               assignee_ids: assignee_ids)
           end
         end
+
+        def valid_weight?
+          board.weight.present? && board.weight >= 0
+        end
       end
     end
   end

ee/changelogs/unreleased/issue_7177.yml

+---
+title: Fix error when creating issues in scoped boards
+merge_request: 11080
+author:
+type: fixed

ee/spec/services/ee/boards/issues/create_service_spec.rb

@@ -35,6 +35,37 @@ describe Boards::Issues::CreateService do
         expect(issue.milestone).to eq(board_milestone)
         expect(issue.labels).to contain_exactly(label, board_label)
       end
+
+      context 'when board is scoped by weight' do
+        it 'creates issue weight 0 weight' do
+          board.update(weight: 0)
+
+          issue = service.execute
+
+          expect(issue.weight).to be_zero
+          expect(issue).to be_valid
+        end
+
+        it 'creates issue with nil weight' do
+          board.update(weight: nil)
+
+          issue = service.execute
+
+          expect(issue.weight).to be_nil
+          expect(issue).to be_valid
+        end
+
+        context 'when board weight is invalid' do
+          it 'creates issue with nil weight' do
+            board.update(weight: -1)
+
+            issue = service.execute
+
+            expect(issue.weight).to be_nil
+            expect(issue).to be_valid
+          end
+        end
+      end
     end
 
     context 'assignees list' do