fix(core): query should reset to default state even when created from hydration

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

@@ -1,6 +1,6 @@
 import { afterEach, beforeEach, describe, expect, it, test, vi } from 'vitest'
 import { waitFor } from '@testing-library/react'
-import { QueryObserver, isCancelledError } from '..'
+import { QueryObserver, dehydrate, hydrate, isCancelledError } from '..'
 import {
   createQueryClient,
   mockOnlineManagerIsOnline,
@@ -389,6 +389,26 @@ describe('query', () => {
     expect(query.state.fetchStatus).toBe('idle') // not be loading any longer
   })
 
+  test('should reset to default state when created from hydration', async () => {
+    const client = createQueryClient()
+    await client.prefetchQuery({
+      queryKey: ['string'],
+      queryFn: () => Promise.resolve('string'),
+    })
+
+    const dehydrated = dehydrate(client)
+
+    const hydrationClient = createQueryClient()
+    hydrate(hydrationClient, dehydrated)
+
+    expect(hydrationClient.getQueryData(['string'])).toBe('string')
+
+    const query = hydrationClient.getQueryCache().find({ queryKey: ['string'] })
+    query?.reset()
+
+    expect(hydrationClient.getQueryData(['string'])).toBe(undefined)
+  })
+
   test('should be able to refetch a cancelled query', async () => {
     const key = queryKey()
 

packages/query-core/src/query.ts

@@ -182,8 +182,8 @@ export class Query<
     this.#cache = config.cache
     this.queryKey = config.queryKey
     this.queryHash = config.queryHash
-    this.#initialState = config.state || getDefaultState(this.options)
-    this.state = this.#initialState
+    this.#initialState = getDefaultState(this.options)
+    this.state = config.state ?? this.#initialState
     this.scheduleGc()
   }
   get meta(): QueryMeta | undefined {