Add explicit error about downstream project not found

ee/app/models/ee/commit_status_enums.rb

@@ -11,7 +11,8 @@ module EE
       def failure_reasons
         super.merge(protected_environment_failure: 1_000,
                     insufficient_bridge_permissions: 1_001,
-                    invalid_bridge_trigger: 1_002)
+                    downstream_bridge_project_not_found: 1_002,
+                    invalid_bridge_trigger: 1_003)
       end
     end
   end

ee/app/presenters/ee/commit_status_presenter.rb

@@ -7,6 +7,7 @@ module EE
       EE_CALLOUT_FAILURE_MESSAGES = const_get(:CALLOUT_FAILURE_MESSAGES).merge(
         protected_environment_failure: 'The environment this job is deploying to is protected. Only users with permission may successfully run this job.',
         insufficient_bridge_permissions: 'This job could not be executed because of insufficient permissions to create a downstream pipeline.',
+        downstream_bridge_project_not_found: 'This job could not be executed because downstream bridge project could not be found.',
         invalid_bridge_trigger: 'This job could not be executed because downstream pipeline trigger definition is invalid.'
       ).freeze
 

ee/app/services/ci/create_cross_project_pipeline_service.rb

@@ -8,7 +8,7 @@ module Ci
       @bridge = bridge
 
       unless target_project_exists?
-        return bridge.drop!(:invalid_bridge_trigger)
+        return bridge.drop!(:downstream_bridge_project_not_found)
       end
 
       if target_project == project

ee/lib/ee/gitlab/ci/status/build/failed.rb

@@ -12,6 +12,7 @@ module EE
               EE_REASONS = const_get(:REASONS).merge(
                 protected_environment_failure: 'protected environment failure',
                 invalid_bridge_trigger: 'downstream pipeline trigger definition is invalid',
+                downstream_bridge_project_not_found: 'downstream project could not be found',
                 insufficient_bridge_permissions: 'no permissions to trigger downstream pipeline'
               ).freeze
 

ee/spec/services/ci/create_cross_project_pipeline_service_spec.rb

@@ -46,7 +46,8 @@ describe Ci::CreateCrossProjectPipelineService, '#execute' do
       service.execute(bridge)
 
       expect(bridge.reload).to be_failed
-      expect(bridge.failure_reason).to eq 'invalid_bridge_trigger'
+      expect(bridge.failure_reason)
+        .to eq 'downstream_bridge_project_not_found'
     end
   end
 
@@ -60,7 +61,8 @@ describe Ci::CreateCrossProjectPipelineService, '#execute' do
       service.execute(bridge)
 
       expect(bridge.reload).to be_failed
-      expect(bridge.failure_reason).to eq 'invalid_bridge_trigger'
+      expect(bridge.failure_reason)
+        .to eq 'downstream_bridge_project_not_found'
     end
   end