[Discover] Fix timefield sorting when switching similar index patterns

src/plugins/discover/public/application/apps/main/utils/get_switch_index_pattern_app_state.test.ts

@@ -98,4 +98,12 @@ describe('Discover getSwitchIndexPatternAppState', () => {
     expect(result.columns).toEqual([]);
     expect(result.sort).toEqual([['timeFieldA', 'desc']]);
   });
+  test('should change sorting for similar index patterns', async () => {
+    const current = getIndexPattern('timebased', 'timefield', ['timefield']);
+    const next = getIndexPattern('timebased2', 'timefield2', ['timefield', 'timefield2']);
+
+    const result = getSwitchIndexPatternAppState(current, next, [], [['timefield', 'desc']]);
+    expect(result.columns).toEqual([]);
+    expect(result.sort).toEqual([['timefield2', 'desc']]);
+  });
 });

src/plugins/discover/public/application/apps/main/utils/get_switch_index_pattern_app_state.ts

@@ -38,9 +38,8 @@ export function getSwitchIndexPatternAppState(
   return {
     index: nextIndexPattern.id,
     columns,
-    sort:
-      nextIndexPattern.timeFieldName && !nextSort.length
-        ? [[nextIndexPattern.timeFieldName, sortDirection]]
-        : nextSort,
+    sort: nextIndexPattern.timeFieldName
+      ? [[nextIndexPattern.timeFieldName, sortDirection]]
+      : nextSort,
   };
 }