Fix migration to sync issuables with unknown states

Allow migration to sync state_id for issuables with unknown states.
Prevents errors when upgrading GitLab.

db/post_migrate/20190911251732_sync_issuables_state_id.rb

@@ -62,6 +62,7 @@ class SyncIssuablesStateId < ActiveRecord::Migration[5.2]
       CASE state
       WHEN 'opened' THEN 1
       WHEN 'closed' THEN 2
+      ELSE 2
       END
     SQL
   end
@@ -73,6 +74,7 @@ class SyncIssuablesStateId < ActiveRecord::Migration[5.2]
       WHEN 'closed' THEN 2
       WHEN 'merged' THEN 3
       WHEN 'locked' THEN 4
+      ELSE 2
       END
     SQL
   end

spec/migrations/sync_issuables_state_id_spec.rb

@@ -19,19 +19,23 @@ describe SyncIssuablesStateId, :migration, :sidekiq do
     it 'migrates state column to state_id as integer' do
       opened_issue = issues.create!(description: 'first', state: 'opened')
       closed_issue = issues.create!(description: 'second', state: 'closed')
+      unknown_state_issue = issues.create!(description: 'second', state: 'unknown')
       opened_merge_request = merge_requests.create!(state: 'opened', target_project_id: project.id, target_branch: 'feature1', source_branch: 'master')
       closed_merge_request = merge_requests.create!(state: 'closed', target_project_id: project.id, target_branch: 'feature2', source_branch: 'master')
       merged_merge_request = merge_requests.create!(state: 'merged', target_project_id: project.id, target_branch: 'feature3', source_branch: 'master')
       locked_merge_request = merge_requests.create!(state: 'locked', target_project_id: project.id, target_branch: 'feature4', source_branch: 'master')
+      unknown_state_merge_request = merge_requests.create!(state: 'unknown', target_project_id: project.id, target_branch: 'feature4', source_branch: 'master')
 
       migrate!
 
       expect(opened_issue.reload.state_id).to eq(state_ids[:opened])
       expect(closed_issue.reload.state_id).to eq(state_ids[:closed])
+      expect(unknown_state_issue.reload.state_id).to eq(state_ids[:closed])
       expect(opened_merge_request.reload.state_id).to eq(state_ids[:opened])
       expect(closed_merge_request.reload.state_id).to eq(state_ids[:closed])
       expect(merged_merge_request.reload.state_id).to eq(state_ids[:merged])
       expect(locked_merge_request.reload.state_id).to eq(state_ids[:locked])
+      expect(unknown_state_merge_request.reload.state_id).to eq(state_ids[:closed])
     end
   end
 end