fix(core): Resolve mock fixture types without @data-client/endpoint

.agents/skills/changeset/no-agent-impact.json

@@ -1,4 +1,4 @@
 {
   "drop-typescript-3": "Agents don't install or keep TypeScript 3.x, so no realistic task hits the old behavior.",
-  "test-mock-reexports": "Agent-written test code and imports are the same before and after; only install-time peer resolution changes, for projects pinned to @data-client/react 0.14 or older."
+  "test-mock-reexports": "Agent-written test code and imports are the same before and after; only install-time peer resolution changes, for projects pinned to @data-client/react 0.15.2 or older."
 }

.changeset/core-mock-fixture-types.md

@@ -0,0 +1,12 @@
+---
+'@data-client/core': patch
+'@data-client/react': patch
+'@data-client/test': patch
+---
+
+Fix fixture types needing `@data-client/endpoint` installed
+
+`Fixture` and the other fixture types from `@data-client/react/mock`, `@data-client/core/mock` and `@data-client/test` no
+longer resolve `@data-client/endpoint`, which those packages don't depend on. Projects that install only
+`@data-client/react` and `@data-client/test` (for example with pnpm's strict layout) no longer get
+`Cannot find module '@data-client/endpoint'` when type-checking fixtures.

.changeset/test-mock-reexports.md

@@ -2,10 +2,11 @@
 '@data-client/test': minor
 ---
 
-BREAKING: `@data-client/test` requires `@data-client/react` 0.15 or later
+BREAKING: `@data-client/test` requires `@data-client/react` 0.15.3 or later
 
-Support for `@data-client/react` 0.12 through 0.14 is dropped, since `@data-client/test` imports
-`@data-client/react/mock`, which first shipped in 0.15. Upgrade `@data-client/react` along with `@data-client/test`.
+Support for `@data-client/react` 0.12 through 0.15.2 is dropped, since `@data-client/test` imports
+`@data-client/react/mock`, which first loads in Jest and other CommonJS tests in 0.15.3. Upgrade `@data-client/react`
+along with `@data-client/test`.
 
 ```diff title="package.json"
 - "@data-client/react": "^0.14.0",

packages/core/src/mock/fixtureTypes.ts

@@ -1,4 +1,4 @@
-import type { EndpointInterface, ResolveType } from '@data-client/endpoint';
+import type { EndpointInterface, ResolveType } from '@data-client/normalizr';
 
 type Updater = (
   result: any,

packages/test/package.json

@@ -109,7 +109,7 @@
     "@testing-library/react": "^16.0.0"
   },
   "peerDependencies": {
-    "@data-client/react": "^0.15.0 || ^0.16.0 || ^0.17.0 || ^0.18.0",
+    "@data-client/react": "^0.15.3 || ^0.16.0 || ^0.17.0 || ^0.18.0",
     "@testing-library/react-hooks": "^8.0.0",
     "@testing-library/react-native": "^13.0.0 || ^14.0.0",
     "@types/react": "^16.14.0 || ^17.0.0 || ^18.0.0 || ^19.0.0-0 || ^19.0.0",

website/blog/2026-10-03-v0.19-batch-set.md

@@ -60,7 +60,7 @@ Coding agents also get a Claude Code plugin, Vue skills and llms.txt; see
 
 - [TypeScript 4.0 or later is required](/blog/2026/10/03/v0.19-batch-set#typescript-4) - the TypeScript 3.x declarations are removed ([#4151](https://github.com/reactive/data-client/pull/4151))
 - [Managers must define `middleware`](/blog/2026/10/03/v0.19-batch-set#manager-middleware) - `getMiddleware()` is removed ([#4378](https://github.com/reactive/data-client/pull/4378), [#4382](https://github.com/reactive/data-client/pull/4382))
-- [@data-client/test requires @data-client/react 0.15 or later](/blog/2026/10/03/v0.19-batch-set#test-react-0.15) ([#4414](https://github.com/reactive/data-client/pull/4414))
+- [@data-client/test requires @data-client/react 0.15.3 or later](/blog/2026/10/03/v0.19-batch-set#test-react-0.15) ([#4414](https://github.com/reactive/data-client/pull/4414))
 
 **[Get ready for future releases:](/blog/2026/10/03/v0.19-batch-set#future-releases)**
 
@@ -797,14 +797,14 @@ class LoggingManager implements Manager {
 
 [#4382](https://github.com/reactive/data-client/pull/4382)
 
-### @data-client/test requires @data-client/react 0.15 {#test-react-0.15}
+### @data-client/test requires @data-client/react 0.15.3 {#test-react-0.15}
 
 Skip this section if you don't use [@data-client/test](https://www.npmjs.com/package/@data-client/test).
 
-`@data-client/test` now builds on `@data-client/react/mock`, which first shipped in `@data-client/react` 0.15, so
-support for 0.12 through 0.14 is dropped. Upgrade `@data-client/react` to the same version as `@data-client/test`, as
-the install command above does. Fixture types imported from `@data-client/test` and from `@data-client/react/mock` are
-now the same types. [#4414](https://github.com/reactive/data-client/pull/4414)
+`@data-client/test` now builds on `@data-client/react/mock`, which first loads in Jest and other CommonJS tests in
+`@data-client/react` 0.15.3, so support for 0.12 through 0.15.2 is dropped. Upgrade `@data-client/react` to the same
+version as `@data-client/test`, as the install command above does. Fixture types imported from `@data-client/test` and
+from `@data-client/react/mock` are now the same types. [#4414](https://github.com/reactive/data-client/pull/4414)
 
 ### Get ready for future releases {#future-releases}