[FIX] Allow filters without index (#68225) (#68349)

* Allow filters without index

* Explicitly return true from isFilterApplicable id no index patterns were provided

* Adjust test result

src/plugins/data/public/ui/filter_bar/filter_item.tsx

@@ -74,7 +74,8 @@ export function FilterItem(props: Props) {
           setIndexPatternExists(false);
         });
     } else {
-      setIndexPatternExists(false);
+      // Allow filters without an index pattern and don't validate them.
+      setIndexPatternExists(true);
     }
   }, [props.filter.meta.index]);
 
@@ -244,6 +245,9 @@ export function FilterItem(props: Props) {
    * This function makes this behavior explicit, but it needs to be revised.
    */
   function isFilterApplicable() {
+    // Any filter is applicable if no index patterns were provided to FilterBar.
+    if (!props.indexPatterns.length) return true;
+
     const ip = getIndexPatternFromFilter(filter, indexPatterns);
     if (ip) return true;
 

test/functional/apps/dashboard/dashboard_filter_bar.js

@@ -217,6 +217,11 @@ export default function ({ getService, getPageObjects }) {
         const hasWarningFieldFilter = await filterBar.hasFilter('extension', 'warn', true);
         expect(hasWarningFieldFilter).to.be(true);
       });
+
+      it('filter without an index pattern is rendred as a warning, if the dashboard has an index pattern', async function () {
+        const noIndexPatternFilter = await filterBar.hasFilter('banana', 'warn', true);
+        expect(noIndexPatternFilter).to.be(true);
+      });
     });
   });
 }