Alerting: Fix UI inheriting mute timings from parent when calculating the polic… (#79295)

* Fix UI inheriting mute timings from parent when calculating the policy tree properties

* Add test for this use case

public/app/features/alerting/unified/components/notification-policies/Policy.test.tsx

@@ -134,7 +134,7 @@ describe('Policy', () => {
     expect(within(secondPolicy).getByTestId('label-matchers')).toHaveTextContent(/^region \= EMEA$/);
     expect(within(secondPolicy).queryByTestId('continue-matching')).not.toBeInTheDocument();
     expect(within(secondPolicy).queryByTestId('mute-timings')).not.toBeInTheDocument();
-    expect(within(secondPolicy).getByTestId('inherited-properties')).toHaveTextContent('Inherited4 properties');
+    expect(within(secondPolicy).getByTestId('inherited-properties')).toHaveTextContent('Inherited3 properties');
 
     // third custom policy should be correct
     const thirdPolicy = customPolicies[2];

public/app/features/alerting/unified/utils/notification-policies.test.ts

@@ -1,11 +1,11 @@
 import { MatcherOperator, Route, RouteWithID } from 'app/plugins/datasource/alertmanager/types';
 
 import {
-  findMatchingRoutes,
-  normalizeRoute,
-  getInheritedProperties,
   computeInheritedTree,
+  findMatchingRoutes,
+  getInheritedProperties,
   matchLabels,
+  normalizeRoute,
 } from './notification-policies';
 
 import 'core-js/stable/structured-clone';
@@ -294,6 +294,21 @@ describe('getInheritedProperties()', () => {
       expect(childInherited).toHaveProperty('group_interval', '2m');
     });
   });
+  it('should not inherit mute timings from parent route', () => {
+    const parent: Route = {
+      receiver: 'PARENT',
+      group_by: ['parentLabel'],
+      mute_time_intervals: ['Mon-Fri 09:00-17:00'],
+    };
+
+    const child: Route = {
+      receiver: 'CHILD',
+      group_by: ['childLabel'],
+    };
+
+    const childInherited = getInheritedProperties(parent, child);
+    expect(childInherited).not.toHaveProperty('mute_time_intervals');
+  });
 });
 
 describe('computeInheritedTree', () => {

public/app/features/alerting/unified/utils/notification-policies.ts

@@ -169,7 +169,6 @@ function getInheritedProperties(
     'group_wait',
     'group_interval',
     'repeat_interval',
-    'mute_time_intervals',
   ]);
 
   // TODO how to solve this TypeScript mystery?