Fallback to the default value stream

When there are no value streams available
we should fall back to `default`.

Adds a `fetchValueStreamData` action

ee/app/assets/javascripts/analytics/cycle_analytics/store/actions.js

@@ -311,12 +311,15 @@ export const createValueStream = ({ commit, dispatch, getters }, data) => {
     });
 };
 
-export const setSelectedValueStream = ({ commit, dispatch }, streamId) => {
-  commit(types.SET_SELECTED_VALUE_STREAM, streamId);
-  return Promise.resolve()
+export const fetchValueStreamData = ({ dispatch }) =>
+  Promise.resolve()
     .then(() => dispatch('fetchGroupStagesAndEvents'))
     .then(() => dispatch('fetchStageMedianValues'))
     .then(() => dispatch('durationChart/fetchDurationData'));
+
+export const setSelectedValueStream = ({ commit, dispatch }, streamId) => {
+  commit(types.SET_SELECTED_VALUE_STREAM, streamId);
+  return dispatch('fetchValueStreamData');
 };
 
 export const receiveValueStreamsSuccess = ({ commit, dispatch }, data = []) => {
@@ -344,5 +347,5 @@ export const fetchValueStreams = ({ commit, dispatch, getters, state }) => {
         commit(types.RECEIVE_VALUE_STREAMS_ERROR, data);
       });
   }
-  return dispatch('fetchGroupStagesAndEvents');
+  return dispatch('fetchValueStreamData');
 };

ee/app/assets/javascripts/analytics/cycle_analytics/store/getters.js

@@ -3,10 +3,12 @@ import { isNumber } from 'lodash';
 import httpStatus from '~/lib/utils/http_status';
 import { dateFormats } from '../../shared/constants';
 import { transformStagesForPathNavigation } from '../utils';
+import { DEFAULT_VALUE_STREAM_ID } from '../constants';
 
 export const hasNoAccessError = state => state.errorCode === httpStatus.FORBIDDEN;
 
-export const currentValueStreamId = ({ selectedValueStream }) => selectedValueStream?.id || null;
+export const currentValueStreamId = ({ selectedValueStream }) =>
+  selectedValueStream?.id || DEFAULT_VALUE_STREAM_ID;
 
 export const currentGroupPath = ({ selectedGroup }) =>
   selectedGroup && selectedGroup.fullPath ? selectedGroup.fullPath : null;

ee/changelogs/unreleased/233439-vsa-requests-fail-without-value_stream_analytics_create_multipl.yml

+---
+title: VSA requests fail without multiple value streams feature flag
+merge_request: 38542
+author:
+type: fixed

ee/spec/features/analytics/cycle_analytics/cycle_analytics_spec.rb

@@ -22,6 +22,7 @@ RSpec.describe 'Group Value Stream Analytics', :js do
   stage_nav_selector = '.stage-nav'
   path_nav_selector = '.js-path-navigation'
   filter_bar_selector = '.js-filter-bar'
+  duration_stage_selector = '.js-dropdown-stages'
 
   3.times do |i|
     let_it_be("issue_#{i}".to_sym) { create(:issue, title: "New Issue #{i}", project: project, created_at: 2.days.ago) }
@@ -189,6 +190,25 @@ RSpec.describe 'Group Value Stream Analytics', :js do
     end
   end
 
+  # Adding this context as part of a fix for https://gitlab.com/gitlab-org/gitlab/-/issues/233439
+  # This can be removed when the feature flag is removed
+  context 'create multiple value streams disabled' do
+    before do
+      stub_feature_flags(value_stream_analytics_create_multiple_value_streams: false)
+
+      visit analytics_cycle_analytics_path
+      select_group
+    end
+
+    it 'displays the list of stages' do
+      expect(page).to have_selector(stage_nav_selector, visible: true)
+    end
+
+    it 'displays the duration chart' do
+      expect(page).to have_selector(duration_stage_selector, visible: true)
+    end
+  end
+
   def wait_for_stages_to_load
     expect(page).to have_selector '.js-stage-table'
   end
@@ -962,7 +982,7 @@ RSpec.describe 'Group Value Stream Analytics', :js do
       end
 
       context 'Duration chart' do
-        let(:duration_chart_dropdown) { page.find('.js-dropdown-stages') }
+        let(:duration_chart_dropdown) { page.find(duration_stage_selector) }
 
         let_it_be(:translated_default_stage_names) do
           Gitlab::Analytics::CycleAnalytics::DefaultStages.names.map do |name|

ee/spec/frontend/analytics/cycle_analytics/store/actions_spec.js

@@ -97,11 +97,7 @@ describe('Cycle analytics actions', () => {
         vs,
         { ...state, selectedValueStream: {} },
         [{ type: types.SET_SELECTED_VALUE_STREAM, payload: vs }],
-        [
-          { type: 'fetchGroupStagesAndEvents' },
-          { type: 'fetchStageMedianValues' },
-          { type: 'durationChart/fetchDurationData' },
-        ],
+        [{ type: 'fetchValueStreamData' }],
       );
     });
   });
@@ -1035,13 +1031,37 @@ describe('Cycle analytics actions', () => {
       });
 
       it(`will dispatch the 'fetchGroupStagesAndEvents' request`, () =>
-        testAction(
-          actions.fetchValueStreams,
-          null,
-          state,
-          [],
-          [{ type: 'fetchGroupStagesAndEvents' }],
-        ));
+        testAction(actions.fetchValueStreams, null, state, [], [{ type: 'fetchValueStreamData' }]));
+    });
+  });
+
+  describe('fetchValueStreamData', () => {
+    beforeEach(() => {
+      state = {
+        ...state,
+        stages: [{ slug: selectedStageSlug }],
+        selectedGroup,
+        featureFlags: {
+          ...state.featureFlags,
+          hasCreateMultipleValueStreams: true,
+        },
+      };
+      mock = new MockAdapter(axios);
+      mock.onGet(endpoints.valueStreamData).reply(httpStatusCodes.OK, { stages: [], events: [] });
+    });
+
+    it('dispatches fetchGroupStagesAndEvents, fetchStageMedianValues and durationChart/fetchDurationData', () => {
+      return testAction(
+        actions.fetchValueStreamData,
+        null,
+        state,
+        [],
+        [
+          { type: 'fetchGroupStagesAndEvents' },
+          { type: 'fetchStageMedianValues' },
+          { type: 'durationChart/fetchDurationData' },
+        ],
+      );
     });
   });
 });