bug: infiniteQueryBehavior fetchPage rejects with undefined when cancelled instead of propagating AbortSignal reason

[kuishou68]

Bug Report

Describe the Bug

In packages/query-core/src/infiniteQueryBehavior.ts, the internal fetchPage helper function calls Promise.reject() without any argument (i.e., rejects with undefined) when the query has been cancelled via the AbortSignal:

const fetchPage = async (
  data: InfiniteData<unknown>,
  param: unknown,
  previous?: boolean,
): Promise<InfiniteData<unknown>> => {
  if (cancelled) {
    return Promise.reject()  // rejects with undefined, not a proper error
  }
  // ...
}

The cancelled flag is set to true by the AbortSignal abort event listener (via addConsumeAwareSignal). When abortController.abort() is called in query.ts (inside onCancel), the signal fires and cancelled becomes true. On the next fetchPage invocation within the multi-page fetch loop, the rejection propagates undefined as the error reason rather than a meaningful AbortError (i.e., context.signal.reason).

Impact

1. Custom retry functions receive undefined as the error argument instead of an AbortError, breaking any logic that inspects the error type.
2. onError / onSettled callbacks in QueryCache config receive undefined as the error.
3. Error boundaries using throwOnError may receive undefined instead of a real error, leading to confusing error messages.

Steps to Reproduce

const client = new QueryClient({
  queryCache: new QueryCache({
    onError: (error) => {
      console.log("error is:", error)          // logs: "error is: undefined"
      console.log(error instanceof DOMException) // false (should be true)
    }
  })
})

client.fetchInfiniteQuery({
  queryKey: ["items"],
  queryFn: async ({ pageParam }) => {
    await new Promise(r => setTimeout(r, 200))
    return { items: [pageParam], nextCursor: pageParam + 1 }
  },
  getNextPageParam: (lastPage) => lastPage.nextCursor,
  initialPageParam: 0,
  pages: 3,
})

// Cancel while fetching page 2 (after ~250ms, first page done)
setTimeout(() => client.cancelQueries({ queryKey: ["items"] }), 250)

Expected Behavior

Promise.reject() should propagate the actual abort reason:

if (cancelled) {
  return Promise.reject(context.signal.reason)
  // context.signal.reason is a DOMException{ name: "AbortError" }
  // when abortController.abort() is called without an explicit reason
}

This matches the Web standard: AbortSignal.reason is automatically set to a DOMException with name "AbortError" when AbortController.abort() is called without an argument.

Environment

• @tanstack/query-core: v5.x (latest)
• Affects: useInfiniteQuery, useSuspenseInfiniteQuery, prefetchInfiniteQuery

[kuishou68]

I have submitted a fix for this in PR #10476.

The change is a one-line fix in infiniteQueryBehavior.ts — replacing Promise.reject() with Promise.reject(context.signal.reason) so that the proper AbortError DOMException is propagated when the query is cancelled during a multi-page infinite query fetch.