Transformations: Transformation refID filters should include non-existant refIDs if no recovery was made (#109008)

* Show refIds if nothing is recovered

* Add test

* Preserve function returning undefined if there are no recovered or selected refIDs

* cuter

* add context and remove testing by sibling

---------

Co-authored-by: Leon Sorokin <leeoniya@gmail.com>

packages/grafana-ui/src/components/MatchersUI/FieldsByFrameRefIdMatcher.test.tsx

@@ -109,4 +109,10 @@ describe('RefIDMultiPicker', () => {
     expect(mockOnChange).toHaveBeenLastCalledWith(['A', 'B']);
     /* eslint-enable testing-library/prefer-user-event */
   });
+
+  // in the scenario where a refID filter was saved, but is no longer valid, it should still show.
+  it('Should display a refID that does not exist in the selection', async () => {
+    multiSetup({ value: '/^(?:merge-A-B-C)$/' });
+    expect(screen.getByText('merge-A-B-C')).toBeInTheDocument();
+  });
 });

packages/grafana-ui/src/components/MatchersUI/FieldsByFrameRefIdMatcher.tsx

@@ -129,7 +129,6 @@ export function RefIDMultiPicker({ value, data, onChange, placeholder }: MultiPr
 
   const currentValue = useMemo(() => {
     let extractedRefIds = new Set<string>();
-
     if (value) {
       if (value.startsWith('/^')) {
         try {
@@ -152,8 +151,10 @@ export function RefIDMultiPicker({ value, data, onChange, placeholder }: MultiPr
     }
 
     const newRefIds = [...extractedRefIds].map(toOption);
+    const recoveredRefIDs =
+      recoverMultiRefIdMissing(newRefIds, priorSelectionState.refIds, priorSelectionState.value) ?? [];
 
-    return recoverMultiRefIdMissing(newRefIds, priorSelectionState.refIds, priorSelectionState.value);
+    return recoveredRefIDs.length > 0 ? recoveredRefIDs : newRefIds.length > 0 ? newRefIds : undefined;
   }, [value, listOfRefIds, priorSelectionState]);
 
   const onFilterChange = useCallback(