fix(store): support null-prototype objects on the server

.changeset/server-null-prototype-stores.md

@@ -0,0 +1,5 @@
+---
+"solid-js": patch
+---
+
+Support null-prototype objects in server store producers, reconciliation, and nested partial updates.

packages/solid/store/src/server.ts

@@ -18,10 +18,11 @@ export type {
 export const $RAW = Symbol("state-raw");
 
 export function isWrappable(obj: any) {
+  let proto;
   return (
     obj != null &&
     typeof obj === "object" &&
-    (Object.getPrototypeOf(obj) === Object.prototype || Array.isArray(obj))
+    (!(proto = Object.getPrototypeOf(obj)) || proto === Object.prototype || Array.isArray(obj))
   );
 }
 

packages/solid/test/server/null-prototype-store.spec.ts

@@ -0,0 +1,41 @@
+import { describe, expect, test } from "vitest";
+import { createStore, produce, reconcile } from "../../store/src/server.js";
+
+describe("null-prototype stores on the server", () => {
+  test("runs producers on a null-prototype object", () => {
+    const original = Object.assign(Object.create(null), { count: 1 });
+    const [state, setState] = createStore<{ count: number }>(original);
+
+    setState(produce(state => state.count++));
+
+    expect(state.count).toBe(2);
+    expect(state).toBe(original);
+    expect(Object.getPrototypeOf(state)).toBeNull();
+  });
+
+  test("reconciles removed properties of a null-prototype object", () => {
+    const original = Object.assign(Object.create(null), { count: 1, removed: true });
+    const [state, setState] = createStore<{ count: number; removed?: boolean }>(original);
+
+    setState(reconcile({ count: 2 }));
+
+    expect(state.count).toBe(2);
+    expect("removed" in state).toBe(false);
+    expect(state).toBe(original);
+    expect(Object.getPrototypeOf(state)).toBeNull();
+  });
+
+  test("merges partial updates into a nested null-prototype object", () => {
+    const original = Object.assign(Object.create(null), { count: 1, label: "kept" });
+    const [state, setState] = createStore<{ data: { count: number; label: string } }>({
+      data: original
+    });
+
+    setState("data", { count: 2 });
+
+    expect(state.data.count).toBe(2);
+    expect(state.data.label).toBe("kept");
+    expect(state.data).toBe(original);
+    expect(Object.getPrototypeOf(state.data)).toBeNull();
+  });
+});