snapshot of https://github.com/TanStack/query.git (main, 2026-09-16; blobs > 131072B omitted)

2026-09-16 01:13:08 +05:00
commit 3a013ccdfe
3570 changed files with 490194 additions and 0 deletions
--- a/packages/query-broadcast-client-experimental/CHANGELOG.md
+++ b/packages/query-broadcast-client-experimental/CHANGELOG.md
@@ -0,0 +1,452 @@
+# @tanstack/query-broadcast-client-experimental
+
+## 5.102.8
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.102.8
+
+## 5.102.7
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.102.7
+
+## 5.102.6
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.102.6
+
+## 5.102.5
+
+### Patch Changes
+
+- Updated dependencies [[`578e5c2`](https://github.com/TanStack/query/commit/578e5c26e8ebd0d7351b4b8e2bafba695e672b8d)]:
+  - @tanstack/query-core@5.102.5
+
+## 5.102.4
+
+### Patch Changes
+
+- Updated dependencies [[`a05df6a`](https://github.com/TanStack/query/commit/a05df6aefb0e2489ec2c879ae16e2ee7cb3123ec)]:
+  - @tanstack/query-core@5.102.4
+
+## 5.102.3
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.102.3
+
+## 5.102.2
+
+### Patch Changes
+
+- Updated dependencies [[`80fbf73`](https://github.com/TanStack/query/commit/80fbf73e77892d702c107e14a84c219a8ed825dc)]:
+  - @tanstack/query-core@5.102.2
+
+## 5.102.1
+
+### Patch Changes
+
+- Updated dependencies [[`134890d`](https://github.com/TanStack/query/commit/134890dbdc60e4fb0313e44b512d29284ca82f96)]:
+  - @tanstack/query-core@5.102.1
+
+## 5.102.0
+
+### Patch Changes
+
+- [#11242](https://github.com/TanStack/query/pull/11242) [`6796c51`](https://github.com/TanStack/query/commit/6796c512752ac95b1b593df91b20d5d416c1b69f) - fix(broadcast-client): recover from errors thrown while applying an incoming cross-tab message instead of permanently disabling this tab's own broadcasts
+
+- [#10771](https://github.com/TanStack/query/pull/10771) [`3c79861`](https://github.com/TanStack/query/commit/3c79861ab1bf00152ed1f8ae03934d90a131dcd1) - Fix unhandled `DataCloneError` rejections in `broadcastQueryClient` when `postMessage` fails due to non-cloneable query data (e.g. `ReadableStream`, `Response`, Vue reactive proxies). Adds an optional `onBroadcastError` callback to handle errors explicitly; falls back to `console.warn` in development when not provided.
+
+- Updated dependencies [[`34f7cee`](https://github.com/TanStack/query/commit/34f7ceed09c10e4a3aa2df31a106ddf02ec4e787), [`b4368c4`](https://github.com/TanStack/query/commit/b4368c43792349f6c29d1fb41f7ee1ef3a8bdd2c), [`5bb089d`](https://github.com/TanStack/query/commit/5bb089d153d33933983b7ea80f8d69b51d423698), [`ba4650c`](https://github.com/TanStack/query/commit/ba4650c05e61e33c609e051b948c9f7d31ce70d1), [`294d4e6`](https://github.com/TanStack/query/commit/294d4e62c4f7d674574a4903eef2a1bc3dd1413b), [`1f631b3`](https://github.com/TanStack/query/commit/1f631b3604aab6567fb3f6c90646a5a304641546), [`01a02bf`](https://github.com/TanStack/query/commit/01a02bfad32f9efbc17796be31d6399f1197a655), [`18c1c1e`](https://github.com/TanStack/query/commit/18c1c1ef94883e781ad36d36f9ea4a043ce4260b), [`5448063`](https://github.com/TanStack/query/commit/5448063f828d2270dccd41ae375e1afde35e91f2), [`2215bb0`](https://github.com/TanStack/query/commit/2215bb031139cdc8a84751b37a485c38ca9d2b6e), [`1ef4208`](https://github.com/TanStack/query/commit/1ef42087c9a266c2137d2ef645cbcc662f60ac93), [`5981771`](https://github.com/TanStack/query/commit/5981771abec9330b344a2617543eb05ba7c99e24), [`4a9bef6`](https://github.com/TanStack/query/commit/4a9bef6cf19b1cd6b014032d696129f12a848185), [`bef4bc7`](https://github.com/TanStack/query/commit/bef4bc780ce7cca32b7e3dea85f77d92f82a62a2), [`9656dc4`](https://github.com/TanStack/query/commit/9656dc4e5fef5f8c502579b52459f9e8c72e787c), [`326aaf1`](https://github.com/TanStack/query/commit/326aaf1333e5d9cbc46569c53f218d31684162d2), [`3e83601`](https://github.com/TanStack/query/commit/3e836010032c2586e9f1c66a271fa9114a6401f9), [`c6fc17c`](https://github.com/TanStack/query/commit/c6fc17cfad6e452261c585fabfb8c210e60531ed)]:
+  - @tanstack/query-core@5.102.0
+
+## 5.101.4
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.101.4
+
+## 5.101.3
+
+### Patch Changes
+
+- Updated dependencies [[`7e3c822`](https://github.com/TanStack/query/commit/7e3c822a10896f41a8f1031c16b85096277af677)]:
+  - @tanstack/query-core@5.101.3
+
+## 5.101.2
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.101.2
+
+## 5.101.1
+
+### Patch Changes
+
+- Updated dependencies [[`9eff92e`](https://github.com/TanStack/query/commit/9eff92ed86e284ec0125b3a3539d028688235bd1)]:
+  - @tanstack/query-core@5.101.1
+
+## 5.101.0
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.101.0
+
+## 5.100.14
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.100.14
+
+## 5.100.13
+
+### Patch Changes
+
+- Updated dependencies [[`d423168`](https://github.com/TanStack/query/commit/d423168f6261a5cb3d353e53b27c8150cc271151)]:
+  - @tanstack/query-core@5.100.13
+
+## 5.100.12
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.100.12
+
+## 5.100.11
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.100.11
+
+## 5.100.10
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.100.10
+
+## 5.100.9
+
+### Patch Changes
+
+- Updated dependencies [[`fcee7bd`](https://github.com/TanStack/query/commit/fcee7bdc429385ae8ffa224fa8a7a9ec7b8ee380)]:
+  - @tanstack/query-core@5.100.9
+
+## 5.100.8
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.100.8
+
+## 5.100.7
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.100.7
+
+## 5.100.6
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.100.6
+
+## 5.100.5
+
+### Patch Changes
+
+- Updated dependencies [[`a53ef97`](https://github.com/TanStack/query/commit/a53ef97f87decb8ea2431710f5199431d3c94c8d)]:
+  - @tanstack/query-core@5.100.5
+
+## 5.100.4
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.100.4
+
+## 5.100.3
+
+### Patch Changes
+
+- Updated dependencies [[`f85d825`](https://github.com/TanStack/query/commit/f85d825e02efbbff02e2081528ed28f5e5382f7a)]:
+  - @tanstack/query-core@5.100.3
+
+## 5.100.2
+
+### Patch Changes
+
+- Updated dependencies [[`ea4497e`](https://github.com/TanStack/query/commit/ea4497e8aa00d8c1c3a36fb1e17563a889d6ab31), [`d6a7bf3`](https://github.com/TanStack/query/commit/d6a7bf3e3e024c1a77d0536813238cc8007a5fa7), [`645d5d1`](https://github.com/TanStack/query/commit/645d5d130f5e8017cb1bf1a37987f7b980aed705)]:
+  - @tanstack/query-core@5.100.2
+
+## 5.100.1
+
+### Patch Changes
+
+- Updated dependencies [[`1bb0d23`](https://github.com/TanStack/query/commit/1bb0d234280fd4ae1725c439088426a20593a8df)]:
+  - @tanstack/query-core@5.100.1
+
+## 5.100.0
+
+### Patch Changes
+
+- Updated dependencies [[`6540a41`](https://github.com/TanStack/query/commit/6540a4126b1c087d86d64525e78f32d9920dcd31)]:
+  - @tanstack/query-core@5.100.0
+
+## 5.99.2
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.99.2
+
+## 5.99.1
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.99.1
+
+## 5.99.0
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.99.0
+
+## 5.98.0
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.98.0
+
+## 5.97.0
+
+### Patch Changes
+
+- Updated dependencies [[`2bfb12c`](https://github.com/TanStack/query/commit/2bfb12cc44f1d8495106136e4ddacb817135f8f9)]:
+  - @tanstack/query-core@5.97.0
+
+## 5.96.2
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.96.2
+
+## 5.96.1
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.96.1
+
+## 5.96.0
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.96.0
+
+## 5.95.2
+
+### Patch Changes
+
+- Updated dependencies [[`cd5a35b`](https://github.com/TanStack/query/commit/cd5a35b328837781aa4f9305bb2bd7877ca934e9)]:
+  - @tanstack/query-core@5.95.2
+
+## 5.95.1
+
+### Patch Changes
+
+- Updated dependencies [[`1f1775c`](https://github.com/TanStack/query/commit/1f1775ca92f2b6c035682947ff3b3424804ff31a)]:
+  - @tanstack/query-core@5.95.1
+
+## 5.95.0
+
+### Patch Changes
+
+- Updated dependencies []:
+  - @tanstack/query-core@5.95.0
+
+## 5.94.5
+
+### Patch Changes
+
+- fix(\*): resolve issue about excluded build directory ([#10312](https://github.com/TanStack/query/pull/10312))
+
+- Updated dependencies [[`4b6536d`](https://github.com/TanStack/query/commit/4b6536dfce99036f4e37f52943c6fed3ad0e0a18)]:
+  - @tanstack/query-core@5.94.5
+
+## 5.94.4
+
+### Patch Changes
+
+- chore: fixed version ([#10064](https://github.com/TanStack/query/pull/10064))
+
+- Updated dependencies [[`4c75210`](https://github.com/TanStack/query/commit/4c75210ce8235fe3d39b67e1029eff11278927cc)]:
+  - @tanstack/query-core@5.94.4
+
+## 5.90.23
+
+### Patch Changes
+
+- fix(streamedQuery): maintain error state on reset refetch with initialData defined ([#10287](https://github.com/TanStack/query/pull/10287))
+
+- Updated dependencies [[`248975e`](https://github.com/TanStack/query/commit/248975e896f585f6eaa505c796e73fcf7bfd1eec)]:
+  - @tanstack/query-core@5.91.2
+
+## 5.90.22
+
+### Patch Changes
+
+- Updated dependencies [[`a89aab9`](https://github.com/TanStack/query/commit/a89aab975581c25c113a26c8af486b4cafad272a)]:
+  - @tanstack/query-core@5.91.1
+
+## 5.90.21
+
+### Patch Changes
+
+- Updated dependencies [[`6fa901b`](https://github.com/TanStack/query/commit/6fa901b97a22a80d0fca3f6ed86237ff0cbdd13b)]:
+  - @tanstack/query-core@5.91.0
+
+## 5.90.20
+
+### Patch Changes
+
+- Updated dependencies [[`e7258c5`](https://github.com/TanStack/query/commit/e7258c5cb30cafa456cdb4e6bc75b43bf619954d)]:
+  - @tanstack/query-core@5.90.20
+
+## 5.90.19
+
+### Patch Changes
+
+- Updated dependencies [[`53fc74e`](https://github.com/TanStack/query/commit/53fc74ebb16730bd3317f039a69c6821386bae93)]:
+  - @tanstack/query-core@5.90.19
+
+## 5.90.18
+
+### Patch Changes
+
+- Updated dependencies [[`dea1614`](https://github.com/TanStack/query/commit/dea1614aaad5c572cf43cea54b64ac09dc4d5b41)]:
+  - @tanstack/query-core@5.90.18
+
+## 5.90.17
+
+### Patch Changes
+
+- Updated dependencies [[`269351b`](https://github.com/TanStack/query/commit/269351b8ce4b4846da3d320ac5b850ee6aada0d6)]:
+  - @tanstack/query-core@5.90.17
+
+## 5.90.16
+
+### Patch Changes
+
+- Updated dependencies [[`7f47906`](https://github.com/TanStack/query/commit/7f47906eaccc3f3aa5ce24b77a83bd7a620a237b)]:
+  - @tanstack/query-core@5.90.16
+
+## 5.90.15
+
+### Patch Changes
+
+- Updated dependencies [[`fccef79`](https://github.com/TanStack/query/commit/fccef797d57d4a9566517bba87c8377f363920f2)]:
+  - @tanstack/query-core@5.90.15
+
+## 5.90.14
+
+### Patch Changes
+
+- Updated dependencies [[`d576092`](https://github.com/TanStack/query/commit/d576092e2ece4ca3936add3eb0da5234c1d82ed4)]:
+  - @tanstack/query-core@5.90.14
+
+## 5.90.13
+
+### Patch Changes
+
+- Updated dependencies [[`4a0a78a`](https://github.com/TanStack/query/commit/4a0a78afbc2432f8cb6828035965853fa98c86a0)]:
+  - @tanstack/query-core@5.90.13
+
+## 5.90.12
+
+### Patch Changes
+
+- Updated dependencies [[`72d8ac5`](https://github.com/TanStack/query/commit/72d8ac5c592004b8f9c3ee086fcb9c3cd615ca05)]:
+  - @tanstack/query-core@5.90.12
+
+## 5.90.11
+
+### Patch Changes
+
+- Updated dependencies [[`c01b150`](https://github.com/TanStack/query/commit/c01b150e3673e11d6533768529a5e6fe3ebee68c)]:
+  - @tanstack/query-core@5.90.11
+
+## 5.90.10
+
+### Patch Changes
+
+- Updated dependencies [[`8e2e174`](https://github.com/TanStack/query/commit/8e2e174e9fd2e7b94cd232041e49c9d014d74e26), [`eb559a6`](https://github.com/TanStack/query/commit/eb559a66dc0d77dd46435f624fa64fc068bef9ae)]:
+  - @tanstack/query-core@5.90.10
+
+## 5.90.9
+
+### Patch Changes
+
+- Updated dependencies [[`08b211f`](https://github.com/TanStack/query/commit/08b211f8aa475e05d2f13a36517fc556861ef962)]:
+  - @tanstack/query-core@5.90.9
+
+## 5.90.8
+
+### Patch Changes
+
+- Updated dependencies [[`c0ec9fe`](https://github.com/TanStack/query/commit/c0ec9fe0d1426fe3f233adda3ebf23989ffaa110)]:
+  - @tanstack/query-core@5.90.8
+
+## 5.90.7
+
+### Patch Changes
+
+- Updated dependencies [[`b4cd121`](https://github.com/TanStack/query/commit/b4cd121a39d07cefaa3a3411136d342cc54ce8fb)]:
+  - @tanstack/query-core@5.90.7
+
+## 5.90.6
+
+### Patch Changes
+
+- Updated dependencies [[`1638c02`](https://github.com/TanStack/query/commit/1638c028df55648995d04431179904371a189772)]:
+  - @tanstack/query-core@5.90.6
+
+## 5.90.5
+
+### Patch Changes
+
+- Updated dependencies [[`e42ddfe`](https://github.com/TanStack/query/commit/e42ddfe919f34f847ca101aeef162c69845f9a1e)]:
+  - @tanstack/query-core@5.90.5
+
+## 5.90.4
+
+### Patch Changes
+
+- Updated dependencies [[`20ef922`](https://github.com/TanStack/query/commit/20ef922a0a7c3aee00150bf69123c338b0922922)]:
+  - @tanstack/query-core@5.90.4
+
+## 5.90.3
+
+### Patch Changes
+
+- Updated dependencies [[`4e1c433`](https://github.com/TanStack/query/commit/4e1c4338a72f7384600bbda99e44bc1891695df4)]:
+  - @tanstack/query-core@5.90.3
--- a/packages/query-broadcast-client-experimental/eslint.config.js
+++ b/packages/query-broadcast-client-experimental/eslint.config.js
@@ -0,0 +1,5 @@
+// @ts-check
+
+import rootConfig from './root.eslint.config.js'
+
+export default [...rootConfig]
--- a/packages/query-broadcast-client-experimental/package.json
+++ b/packages/query-broadcast-client-experimental/package.json
@@ -0,0 +1,67 @@
+{
+  "name": "@tanstack/query-broadcast-client-experimental",
+  "version": "5.102.8",
+  "description": "An experimental plugin to for broadcasting the state of your queryClient between browser tabs/windows",
+  "author": "tannerlinsley",
+  "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/TanStack/query.git",
+    "directory": "packages/query-broadcast-client-experimental"
+  },
+  "homepage": "https://tanstack.com/query",
+  "funding": {
+    "type": "github",
+    "url": "https://github.com/sponsors/tannerlinsley"
+  },
+  "scripts": {
+    "clean": "premove ./build ./coverage ./dist-ts ./.cache/test-types",
+    "compile": "tsc --project tsconfig.json",
+    "test:eslint": "eslint --concurrency=auto ./src",
+    "test:types": "npm-run-all --serial test:types:*",
+    "test:types:ts56": "node ../../node_modules/typescript56/lib/tsc.js --project tsconfig.json --outDir .cache/test-types/ts56 --tsBuildInfoFile .cache/test-types/ts56.tsbuildinfo",
+    "test:types:ts57": "node ../../node_modules/typescript57/lib/tsc.js --project tsconfig.json --outDir .cache/test-types/ts57 --tsBuildInfoFile .cache/test-types/ts57.tsbuildinfo",
+    "test:types:ts58": "node ../../node_modules/typescript58/lib/tsc.js --project tsconfig.json --outDir .cache/test-types/ts58 --tsBuildInfoFile .cache/test-types/ts58.tsbuildinfo",
+    "test:types:ts59": "node ../../node_modules/typescript59/lib/tsc.js --project tsconfig.json --outDir .cache/test-types/ts59 --tsBuildInfoFile .cache/test-types/ts59.tsbuildinfo",
+    "test:types:tscurrent": "tsc --project tsconfig.json --outDir .cache/test-types/tscurrent --tsBuildInfoFile .cache/test-types/tscurrent.tsbuildinfo",
+    "test:types:ts70": "node ../../node_modules/typescript70/lib/tsc.js --project tsconfig.json --outDir .cache/test-types/ts70 --tsBuildInfoFile .cache/test-types/ts70.tsbuildinfo",
+    "test:lib": "vitest",
+    "test:lib:dev": "pnpm run test:lib --watch",
+    "test:build": "publint --strict && attw --pack",
+    "build": "tsdown --tsconfig tsconfig.prod.json"
+  },
+  "type": "module",
+  "types": "build/legacy/index.d.ts",
+  "main": "build/legacy/index.cjs",
+  "module": "build/legacy/index.js",
+  "exports": {
+    ".": {
+      "@tanstack/custom-condition": "./src/index.ts",
+      "import": {
+        "types": "./build/modern/index.d.ts",
+        "default": "./build/modern/index.js"
+      },
+      "require": {
+        "types": "./build/modern/index.d.cts",
+        "default": "./build/modern/index.cjs"
+      }
+    },
+    "./package.json": "./package.json"
+  },
+  "sideEffects": false,
+  "files": [
+    "build",
+    "src",
+    "!src/__tests__"
+  ],
+  "dependencies": {
+    "@tanstack/query-core": "workspace:*",
+    "broadcast-channel": "^7.0.0"
+  },
+  "devDependencies": {
+    "@tanstack/query-test-utils": "workspace:*",
+    "@testing-library/react": "^16.1.0",
+    "@vitejs/plugin-react": "^4.3.4",
+    "npm-run-all2": "^5.0.0"
+  }
+}
--- a/packages/query-broadcast-client-experimental/root.eslint.config.js
+++ b/packages/query-broadcast-client-experimental/root.eslint.config.js
@@ -0,0 +1 @@
+../../eslint.config.js
--- a/packages/query-broadcast-client-experimental/root.tsdown.config.js
+++ b/packages/query-broadcast-client-experimental/root.tsdown.config.js
@@ -0,0 +1 @@
+../../scripts/getTsdownConfig.js
--- a/packages/query-broadcast-client-experimental/src/tests/index.test.ts
+++ b/packages/query-broadcast-client-experimental/src/tests/index.test.ts
@@ -0,0 +1,352 @@
+import { QueryClient } from '@tanstack/query-core'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { queryKey, sleep } from '@tanstack/query-test-utils'
+import { broadcastQueryClient } from '..'
+import type { BroadcastErrorEvent } from '..'
+import type { QueryCache } from '@tanstack/query-core'
+
+const mockPostMessage = vi.fn().mockResolvedValue(undefined)
+const mockClose = vi.fn()
+let lastCreatedChannel: { onmessage: ((action: any) => void) | null }
+
+vi.mock('broadcast-channel', async (importOriginal) => {
+  const actual = await importOriginal()
+  return {
+    ...(actual as object),
+    BroadcastChannel: class MockBroadcastChannel {
+      onmessage = null
+      postMessage = mockPostMessage
+      close = mockClose
+      constructor() {
+        lastCreatedChannel = this
+      }
+    },
+  }
+})
+
+describe('broadcastQueryClient', () => {
+  let queryClient: QueryClient
+  let queryCache: QueryCache
+
+  beforeEach(() => {
+    queryClient = new QueryClient()
+    queryCache = queryClient.getQueryCache()
+    mockPostMessage.mockResolvedValue(undefined)
+    mockClose.mockReset()
+  })
+
+  it('should subscribe to the query cache', () => {
+    broadcastQueryClient({
+      queryClient,
+      broadcastChannel: 'test_channel',
+    })
+    expect(queryCache.hasListeners()).toBe(true)
+  })
+
+  it('should not have any listeners after cleanup', () => {
+    const unsubscribe = broadcastQueryClient({
+      queryClient,
+      broadcastChannel: 'test_channel',
+    })
+    unsubscribe()
+    expect(queryCache.hasListeners()).toBe(false)
+  })
+
+  describe('incoming message handling', () => {
+    it('should keep broadcasting local changes after applying an incoming message throws', () => {
+      const remoteKey = queryKey()
+      const localKey = queryKey()
+
+      broadcastQueryClient({
+        queryClient,
+        broadcastChannel: 'test_channel',
+      })
+
+      // Simulate some other part of the app (e.g. another cache subscriber)
+      // throwing synchronously while an incoming cross-tab message is being
+      // applied locally.
+      const explodingUnsubscribe = queryCache.subscribe(() => {
+        throw new Error('boom from an unrelated cache listener')
+      })
+
+      expect(() => {
+        lastCreatedChannel.onmessage?.({
+          type: 'added',
+          queryHash: JSON.stringify(remoteKey),
+          queryKey: remoteKey,
+          state: { data: 1 },
+        })
+      }).toThrow('boom')
+
+      explodingUnsubscribe()
+      mockPostMessage.mockClear()
+
+      // A later local change must still be broadcast to other tabs, instead
+      // of being silently swallowed because the transaction flag got stuck.
+      queryClient.setQueryData(localKey, { value: 1 })
+
+      expect(mockPostMessage).toHaveBeenCalled()
+    })
+
+    it('should keep broadcasting local changes after query.setState throws for an existing query', () => {
+      const existingKey = queryKey()
+      const localKey = queryKey()
+
+      broadcastQueryClient({
+        queryClient,
+        broadcastChannel: 'test_channel',
+      })
+
+      // Populate the cache with an existing query so the incoming message
+      // below is applied via `query.setState` rather than `queryCache.build`.
+      queryClient.setQueryData(existingKey, { value: 0 })
+      const existingQuery = queryCache.find({ queryKey: existingKey })!
+
+      const explodingUnsubscribe = queryCache.subscribe(() => {
+        throw new Error('boom from an unrelated cache listener')
+      })
+
+      expect(() => {
+        lastCreatedChannel.onmessage?.({
+          type: 'updated',
+          queryHash: existingQuery.queryHash,
+          queryKey: existingKey,
+          state: { data: 2 },
+        })
+      }).toThrow('boom')
+
+      explodingUnsubscribe()
+      mockPostMessage.mockClear()
+
+      queryClient.setQueryData(localKey, { value: 1 })
+
+      expect(mockPostMessage).toHaveBeenCalled()
+    })
+  })
+
+  describe('postMessage error handling', () => {
+    let originalEnv: string | undefined
+
+    beforeEach(() => {
+      originalEnv = process.env['NODE_ENV']
+    })
+
+    afterEach(() => {
+      process.env['NODE_ENV'] = originalEnv
+    })
+
+    it('should not cause an unhandled rejection when onBroadcastError itself throws', async () => {
+      const key = queryKey()
+      const cloneError = new DOMException('DataCloneError', 'DataCloneError')
+      mockPostMessage.mockRejectedValueOnce(cloneError)
+
+      const unhandledRejections: Array<unknown> = []
+      const onUnhandledRejection = (reason: unknown) => {
+        unhandledRejections.push(reason)
+      }
+      process.on('unhandledRejection', onUnhandledRejection)
+
+      try {
+        const onBroadcastError = vi.fn().mockImplementation(() => {
+          throw new Error('boom')
+        })
+
+        broadcastQueryClient({
+          queryClient,
+          broadcastChannel: 'test_channel',
+          onBroadcastError,
+        })
+
+        queryClient.setQueryData(key, { value: 1 })
+
+        await sleep(0)
+
+        expect(onBroadcastError).toHaveBeenCalledWith(
+          cloneError,
+          expect.objectContaining<BroadcastErrorEvent>({
+            type: 'added',
+            queryHash: expect.any(String) as string,
+            queryKey: key,
+          }),
+        )
+        expect(unhandledRejections).toHaveLength(0)
+      } finally {
+        process.off('unhandledRejection', onUnhandledRejection)
+      }
+    })
+
+    it('should warn in dev when onBroadcastError itself throws', async () => {
+      const key = queryKey()
+      process.env['NODE_ENV'] = 'development'
+      const cloneError = new DOMException('DataCloneError', 'DataCloneError')
+      const callbackError = new Error('boom')
+      mockPostMessage.mockRejectedValueOnce(cloneError)
+
+      const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {})
+
+      try {
+        broadcastQueryClient({
+          queryClient,
+          broadcastChannel: 'test_channel',
+          onBroadcastError: () => {
+            throw callbackError
+          },
+        })
+
+        queryClient.setQueryData(key, { value: 1 })
+
+        await sleep(0)
+
+        expect(warnSpy).toHaveBeenCalledWith(
+          expect.stringContaining('onBroadcastError threw while handling'),
+          callbackError,
+        )
+      } finally {
+        warnSpy.mockRestore()
+      }
+    })
+
+    it('should not cause an unhandled rejection when async onBroadcastError rejects', async () => {
+      const key = queryKey()
+      const cloneError = new DOMException('DataCloneError', 'DataCloneError')
+      mockPostMessage.mockRejectedValueOnce(cloneError)
+
+      const unhandledRejections: Array<unknown> = []
+      const onUnhandledRejection = (reason: unknown) => {
+        unhandledRejections.push(reason)
+      }
+      process.on('unhandledRejection', onUnhandledRejection)
+
+      try {
+        const onBroadcastError = vi
+          .fn()
+          .mockRejectedValueOnce(new Error('async boom'))
+
+        broadcastQueryClient({
+          queryClient,
+          broadcastChannel: 'test_channel',
+          onBroadcastError,
+        })
+
+        queryClient.setQueryData(key, { value: 1 })
+
+        await sleep(10)
+
+        expect(onBroadcastError).toHaveBeenCalledWith(
+          cloneError,
+          expect.objectContaining<BroadcastErrorEvent>({
+            type: 'added',
+            queryHash: expect.any(String) as string,
+            queryKey: key,
+          }),
+        )
+        expect(unhandledRejections).toHaveLength(0)
+      } finally {
+        process.off('unhandledRejection', onUnhandledRejection)
+      }
+    })
+
+    it('should warn in dev when async onBroadcastError rejects', async () => {
+      const key = queryKey()
+      process.env['NODE_ENV'] = 'development'
+      const cloneError = new DOMException('DataCloneError', 'DataCloneError')
+      const asyncError = new Error('async boom')
+      mockPostMessage.mockRejectedValueOnce(cloneError)
+
+      const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {})
+
+      try {
+        broadcastQueryClient({
+          queryClient,
+          broadcastChannel: 'test_channel',
+          onBroadcastError: () => Promise.reject(asyncError),
+        })
+
+        queryClient.setQueryData(key, { value: 1 })
+
+        await sleep(10)
+
+        expect(warnSpy).toHaveBeenCalledWith(
+          expect.stringContaining('onBroadcastError threw while handling'),
+          asyncError,
+        )
+      } finally {
+        warnSpy.mockRestore()
+      }
+    })
+
+    it('should call onBroadcastError when postMessage fails', async () => {
+      const key = queryKey()
+      const cloneError = new DOMException('DataCloneError', 'DataCloneError')
+      mockPostMessage.mockRejectedValueOnce(cloneError)
+
+      const onBroadcastError = vi.fn()
+      broadcastQueryClient({
+        queryClient,
+        broadcastChannel: 'test_channel',
+        onBroadcastError,
+      })
+
+      queryClient.setQueryData(key, { value: 1 })
+
+      await sleep(0)
+      expect(onBroadcastError).toHaveBeenCalledWith(
+        cloneError,
+        expect.objectContaining<BroadcastErrorEvent>({
+          type: 'added',
+          queryHash: expect.any(String) as string,
+          queryKey: key,
+        }),
+      )
+    })
+
+    it('should warn in dev when postMessage fails and onBroadcastError is not provided', async () => {
+      const key = queryKey()
+      process.env['NODE_ENV'] = 'development'
+      const cloneError = new DOMException('DataCloneError', 'DataCloneError')
+      mockPostMessage.mockRejectedValueOnce(cloneError)
+
+      const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {})
+
+      try {
+        broadcastQueryClient({
+          queryClient,
+          broadcastChannel: 'test_channel',
+        })
+
+        queryClient.setQueryData(key, { value: 1 })
+
+        await sleep(0)
+        expect(warnSpy).toHaveBeenCalledWith(
+          expect.stringContaining('cross-tab sync for this query was skipped'),
+          cloneError,
+        )
+      } finally {
+        warnSpy.mockRestore()
+      }
+    })
+
+    it('should not warn in production when postMessage fails', async () => {
+      const key = queryKey()
+      process.env['NODE_ENV'] = 'production'
+      const cloneError = new DOMException('DataCloneError', 'DataCloneError')
+      mockPostMessage.mockRejectedValueOnce(cloneError)
+
+      const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {})
+
+      try {
+        broadcastQueryClient({
+          queryClient,
+          broadcastChannel: 'test_channel',
+        })
+
+        queryClient.setQueryData(key, { value: 1 })
+
+        await sleep(0)
+        expect(warnSpy).not.toHaveBeenCalled()
+      } finally {
+        warnSpy.mockRestore()
+      }
+    })
+  })
+})
--- a/packages/query-broadcast-client-experimental/src/index.ts
+++ b/packages/query-broadcast-client-experimental/src/index.ts
@@ -0,0 +1,196 @@
+import { BroadcastChannel } from 'broadcast-channel'
+import type { BroadcastChannelOptions } from 'broadcast-channel'
+import type { QueryClient, QueryKey } from '@tanstack/query-core'
+
+/**
+ * Metadata describing a broadcast that failed to be delivered to other tabs.
+ * Passed to {@link BroadcastQueryClientOptions.onBroadcastError} so callers
+ * can correlate failures with the originating query.
+ */
+export interface BroadcastErrorEvent {
+  type: 'updated' | 'removed' | 'added'
+  queryHash: string
+  queryKey: QueryKey
+}
+
+type BroadcastMessage =
+  | { type: 'updated'; queryHash: string; queryKey: QueryKey; state: unknown }
+  | { type: 'removed'; queryHash: string; queryKey: QueryKey }
+  | { type: 'added'; queryHash: string; queryKey: QueryKey; state: unknown }
+
+interface BroadcastQueryClientOptions {
+  /** The QueryClient to sync. */
+  queryClient: QueryClient
+  /**
+   * Unique channel name used to communicate between tabs and windows.
+   * @default 'tanstack-query'
+   */
+  broadcastChannel?: string
+  /** Options forwarded to the underlying `BroadcastChannel`. */
+  options?: BroadcastChannelOptions
+  /**
+   * Called when a query event fails to broadcast to other tabs — most
+   * commonly because the query's `state.data`, `state.error`, or `queryKey`
+   * contains a value the structured-clone algorithm cannot serialize
+   * (e.g. `ReadableStream`, `File`, functions, Vue `reactive` proxies).
+   *
+   * Provide this to route failures to an error tracker. If omitted, a
+   * `console.warn` is emitted in development so failures are never silent.
+   *
+   * May return a `Promise`; any rejection is caught internally so it cannot
+   * cause a secondary unhandled rejection.
+   */
+  onBroadcastError?: (
+    error: unknown,
+    event: BroadcastErrorEvent,
+  ) => void | Promise<void>
+}
+
+export function broadcastQueryClient({
+  queryClient,
+  broadcastChannel = 'tanstack-query',
+  options,
+  onBroadcastError,
+}: BroadcastQueryClientOptions): () => void {
+  let transaction = false
+  const tx = (cb: () => void) => {
+    transaction = true
+    try {
+      cb()
+    } finally {
+      // Guard against `cb` throwing (e.g. `query.setState`/`queryCache.build`
+      // triggering a listener that throws while applying an incoming
+      // cross-tab message). Without this, `transaction` would stay `true`
+      // forever, silently disabling this tab's own broadcasts to other tabs
+      // for the rest of the session.
+      transaction = false
+    }
+  }
+
+  const channel = new BroadcastChannel(broadcastChannel, {
+    webWorkerSupport: false,
+    ...options,
+  })
+
+  const queryCache = queryClient.getQueryCache()
+
+  const safePost = (message: BroadcastMessage): void => {
+    channel.postMessage(message).catch((error: unknown) => {
+      const event: BroadcastErrorEvent = {
+        type: message.type,
+        queryHash: message.queryHash,
+        queryKey: message.queryKey,
+      }
+
+      if (onBroadcastError) {
+        const warnCallbackError = (callbackError: unknown) => {
+          if (process.env.NODE_ENV !== 'production') {
+            console.warn(
+              `[broadcastQueryClient] onBroadcastError threw while handling "${event.type}" for query ${event.queryHash}.`,
+              callbackError,
+            )
+          }
+        }
+        let result: void | Promise<void>
+        try {
+          result = onBroadcastError(error, event)
+        } catch (callbackError) {
+          warnCallbackError(callbackError)
+          return
+        }
+        result?.catch(warnCallbackError)
+      } else if (process.env.NODE_ENV !== 'production') {
+        console.warn(
+          `[broadcastQueryClient] Failed to broadcast "${event.type}" event for query ${event.queryHash}. ` +
+            'The query value could not be structured-cloned; cross-tab sync for this query was skipped.',
+          error,
+        )
+      }
+    })
+  }
+
+  const unsubscribe = queryCache.subscribe((queryEvent) => {
+    if (transaction) {
+      return
+    }
+
+    const {
+      query: { queryHash, queryKey, state, observers },
+    } = queryEvent
+
+    if (queryEvent.type === 'updated' && queryEvent.action.type === 'success') {
+      safePost({
+        type: 'updated',
+        queryHash,
+        queryKey,
+        state,
+      })
+    }
+
+    if (queryEvent.type === 'removed' && observers.length > 0) {
+      safePost({
+        type: 'removed',
+        queryHash,
+        queryKey,
+      })
+    }
+
+    if (queryEvent.type === 'added') {
+      safePost({
+        type: 'added',
+        queryHash,
+        queryKey,
+        state,
+      })
+    }
+  })
+
+  channel.onmessage = (action) => {
+    if (!action?.type) {
+      return
+    }
+
+    tx(() => {
+      const { type, queryHash, queryKey, state } = action
+
+      const query = queryCache.get(queryHash)
+
+      if (type === 'updated') {
+        if (query) {
+          query.setState(state)
+          return
+        }
+
+        queryCache.build(
+          queryClient,
+          {
+            queryKey,
+            queryHash,
+          },
+          state,
+        )
+      } else if (type === 'removed') {
+        if (query) {
+          queryCache.remove(query)
+        }
+      } else if (type === 'added') {
+        if (query) {
+          query.setState(state)
+          return
+        }
+        queryCache.build(
+          queryClient,
+          {
+            queryKey,
+            queryHash,
+          },
+          state,
+        )
+      }
+    })
+  }
+  return () => {
+    unsubscribe()
+    channel.close()
+  }
+}
--- a/packages/query-broadcast-client-experimental/test-setup.ts
+++ b/packages/query-broadcast-client-experimental/test-setup.ts
@@ -0,0 +1,14 @@
+import '@testing-library/jest-dom/vitest'
+import { act, cleanup as cleanupRTL } from '@testing-library/react'
+import { afterEach } from 'vitest'
+import { notifyManager } from '@tanstack/query-core'
+
+// https://testing-library.com/docs/react-testing-library/api#cleanup
+afterEach(() => {
+  cleanupRTL()
+})
+
+// Wrap notifications with act to make sure React knows about React Query updates
+notifyManager.setNotifyFunction((fn) => {
+  act(fn)
+})
--- a/packages/query-broadcast-client-experimental/tsconfig.json
+++ b/packages/query-broadcast-client-experimental/tsconfig.json
@@ -0,0 +1,15 @@
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "outDir": "./dist-ts",
+    "rootDir": "."
+  },
+  "include": [
+    "src",
+    "test-setup.ts",
+    "*.config.ts",
+    "*.config.js",
+    "package.json"
+  ],
+  "references": [{ "path": "../query-core" }]
+}
--- a/packages/query-broadcast-client-experimental/tsconfig.prod.json
+++ b/packages/query-broadcast-client-experimental/tsconfig.prod.json
@@ -0,0 +1,10 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "incremental": false,
+    "composite": false,
+    "rootDir": "../../"
+  },
+  "include": ["src"],
+  "exclude": ["src/__tests__"]
+}
--- a/packages/query-broadcast-client-experimental/tsdown.config.ts
+++ b/packages/query-broadcast-client-experimental/tsdown.config.ts
@@ -0,0 +1,7 @@
+import { defineConfig } from 'tsdown'
+import { legacyConfig, modernConfig } from './root.tsdown.config.js'
+
+export default defineConfig([
+  modernConfig({ entry: ['src/*.ts'] }),
+  legacyConfig({ entry: ['src/*.ts'] }),
+])
--- a/packages/query-broadcast-client-experimental/vite.config.ts
+++ b/packages/query-broadcast-client-experimental/vite.config.ts
@@ -0,0 +1,35 @@
+import { defineConfig } from 'vitest/config'
+import react from '@vitejs/plugin-react'
+
+import packageJson from './package.json'
+
+export default defineConfig({
+  plugins: [react()],
+  // fix from https://github.com/vitest-dev/vitest/issues/6992#issuecomment-2509408660
+  resolve: {
+    conditions: ['@tanstack/custom-condition'],
+  },
+  environments: {
+    ssr: {
+      resolve: {
+        conditions: ['@tanstack/custom-condition'],
+      },
+    },
+  },
+  test: {
+    name: packageJson.name,
+    dir: './src',
+    watch: false,
+    environment: 'jsdom',
+    setupFiles: ['test-setup.ts'],
+    coverage: {
+      enabled: !!process.env.CI,
+      provider: 'istanbul',
+      include: ['src/**/*'],
+      exclude: ['src/__tests__/**'],
+    },
+    typecheck: { enabled: true },
+    restoreMocks: true,
+    retry: process.env.CI ? 3 : 0,
+  },
+})