fix(query-core): keep selector error timestamps stable

.changeset/stable-selector-error-timestamp.md

@@ -0,0 +1,5 @@
+---
+'@tanstack/query-core': patch
+---
+
+Keep the timestamp stable for the same selector error to prevent infinite render loops.

packages/query-core/src/__tests__/queryObserver.test.tsx

@@ -494,6 +494,26 @@ describe('queryObserver', () => {
     expect(observerResult2.data).toMatchObject({ myCount: 1 })
   })
 
+  it('should keep the result stable when updating a cached selector error', () => {
+    const error = new Error('selector error')
+    const observer = new QueryObserver(queryClient, {
+      queryKey: createKey(),
+      initialData: 'data',
+      enabled: false,
+      select: () => {
+        throw error
+      },
+    })
+    const result = observer.getCurrentResult()
+
+    expect(result).toMatchObject({ status: 'error', error })
+
+    vi.advanceTimersByTime(1)
+    observer.updateResult()
+
+    expect(observer.getCurrentResult()).toBe(result)
+  })
+
   it('should always run the selector again if selector throws an error and selector is not referentially stable', async () => {
     const key = createKey()
     const results: Array<QueryObserverResult> = []

packages/query-core/src/queryObserver.ts

@@ -710,7 +710,8 @@ export class QueryObserver<
     if (this.#selectError) {
       error = this.#selectError
       data = this.#selectResult
-      errorUpdatedAt = Date.now()
+      errorUpdatedAt =
+        prevResult?.error === error ? prevResult.errorUpdatedAt : Date.now()
       status = 'error'
       isPlaceholderData = false
     }