fix(solid-query): don't trigger Suspense when data is already cached

.changeset/solid-query-suspense-ensure-data.md

@@ -0,0 +1,5 @@
+---
+'@tanstack/solid-query': patch
+---
+
+fix(solid-query): avoid triggering Suspense when data is already cached (e.g. via `ensureQueryData`)

packages/solid-query/src/__tests__/suspense.test.tsx

@@ -908,6 +908,47 @@ describe("useQuery's in Suspense mode", () => {
     consoleMock.mockRestore()
   })
 
+  // https://github.com/TanStack/query/issues/9955
+  it('should not trigger Suspense when data was preloaded via ensureQueryData', async () => {
+    const key = queryKey()
+
+    const ensurePromise = queryClient.ensureQueryData({
+      queryKey: key,
+      queryFn: () => sleep(10).then(() => 'preloaded'),
+      staleTime: Infinity,
+    })
+    await vi.advanceTimersByTimeAsync(10)
+    await ensurePromise
+
+    let fallbackMounted = false
+
+    function Page() {
+      const state = useQuery(() => ({
+        queryKey: key,
+        queryFn: () => sleep(10).then(() => 'fresh'),
+        staleTime: Infinity,
+      }))
+
+      return <div>data: {state.data}</div>
+    }
+
+    function Fallback() {
+      fallbackMounted = true
+      return <>loading</>
+    }
+
+    const rendered = render(() => (
+      <QueryClientProvider client={queryClient}>
+        <Suspense fallback={<Fallback />}>
+          <Page />
+        </Suspense>
+      </QueryClientProvider>
+    ))
+
+    expect(rendered.getByText('data: preloaded')).toBeInTheDocument()
+    expect(fallbackMounted).toBe(false)
+  })
+
   it('should render the correct amount of times in Suspense mode when gcTime is set to 0', async () => {
     const key = queryKey()
     let state: UseQueryResult<number> | null = null

packages/solid-query/src/useBaseQuery.ts

@@ -10,6 +10,7 @@ import {
   createSignal,
   on,
   onCleanup,
+  untrack,
 } from 'solid-js'
 import { createStore, reconcile, unwrap } from 'solid-js/store'
 import { useQueryClient } from './QueryClientProvider'
@@ -377,6 +378,14 @@ export function useBaseQuery<
     ): any {
       if (prop === 'data') {
         if (state.data !== undefined) {
+          // When data is already in the store and no fetch is in-flight (e.g.
+          // it was preloaded via `ensureQueryData`), avoid reading the resource
+          // because its initial pending state would otherwise trigger Suspense
+          // on the synchronous-resolve microtask gap. See #9955.
+          // `untrack` keeps `isFetching` from leaking into the data subscriber.
+          if (!untrack(() => state.isFetching)) {
+            return state.data
+          }
           return queryResource.latest?.data
         }
         return queryResource()?.data