From 9abd71d3bdcdc1ff4c5d64d5969eb7e495ee0bad Mon Sep 17 00:00:00 2001
From: Junaid Khan <khanjunaid80121@gmail.com>
Date: Thu, 5 Nov 2026 17:29:12 +0530
Subject: [PATCH] fix(signals): skip IMMUTABLE_UPDATE_IN_STORE for shallow/raw
 leaves

---
 .changeset/shallow-immutable-update-4686.md   |  5 ++++
 packages/signals/src/store/store.ts           |  7 ++++++
 .../attribution-immutable-update.test.ts      | 23 ++++++++++++++++++-
 3 files changed, 34 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/shallow-immutable-update-4686.md

diff --git a/.changeset/shallow-immutable-update-4686.md b/.changeset/shallow-immutable-update-4686.md
new file mode 100644
index 0000000000..a78908e974
--- /dev/null
+++ b/.changeset/shallow-immutable-update-4686.md
@@ -0,0 +1,5 @@
+---
+"@solidjs/signals": patch
+---
+
+`IMMUTABLE_UPDATE_IN_STORE` no longer reports wholesale replacements on a shallow store, or of a `markRaw` / unwrappable leaf (#4686). Those values are invalidated as a unit, so leaf draft assignment does not narrow who re-runs — the diagnostic's advice does not apply.
diff --git a/packages/signals/src/store/store.ts b/packages/signals/src/store/store.ts
index 2d865f3b79..29bef12d46 100644
--- a/packages/signals/src/store/store.ts
+++ b/packages/signals/src/store/store.ts
@@ -1071,6 +1071,10 @@ function reportReplacedContainers(
   pb: Record<PropertyKey, any>,
   writtenKeys: Iterable<PropertyKey> | null
 ): void {
+  // Shallow stores (and raw / unwrappable leaves) invalidate the whole
+  // replaced value as one unit — leaf draft assignment does not narrow
+  // who re-runs (#4686). The spread-copy diagnostic only helps deep stores.
+  if (t.s) return;
   const keys = writtenKeys ?? Reflect.ownKeys(pb);
   const isArray = Array.isArray(pb);
   const owner = storeRootOwner(t);
@@ -1091,6 +1095,9 @@ function reportReplacedContainers(
       targetsEqual(ov, nv)
     )
       continue;
+    // A raw / unwrappable previous value is itself a leaf: replacing it is
+    // the write, not a container copy the store could have mutated in place.
+    if (isRawValue(ov) || !isWrappable(ov)) continue;
     if (isArray) {
       if (oldArrayItems === null) {
         oldArrayItems = new Set<unknown>();
diff --git a/packages/signals/tests/attribution-immutable-update.test.ts b/packages/signals/tests/attribution-immutable-update.test.ts
index 8cd1685888..9424d1e4b7 100644
--- a/packages/signals/tests/attribution-immutable-update.test.ts
+++ b/packages/signals/tests/attribution-immutable-update.test.ts
@@ -6,7 +6,7 @@
  */
 import { afterEach, describe, expect, it, vi } from "vitest";
 import { attribution } from "../src/attribution.js";
-import { createStore, flush, reconcile, OBSERVE } from "../src/index.js";
+import { createStore, flush, markRaw, reconcile, OBSERVE } from "../src/index.js";
 import type { DiagnosticEvent } from "../src/core/dev.js";
 
 afterEach(() => {
@@ -174,4 +174,25 @@ describe("IMMUTABLE_UPDATE_IN_STORE", () => {
     expect(hits).toHaveLength(1);
     expect(hits[0].data!.path).toBe("store.a.b");
   });
+
+  it("does not report replacing a value in a shallow store (#4686)", () => {
+    const hits = arm();
+    const [, setStore] = createStore([{ a: 1, b: 2, c: 3 }], { shallow: true });
+    setStore(s => {
+      s[0] = { a: 1, b: 2, c: 4 };
+    });
+    flush();
+    expect(hits).toEqual([]);
+  });
+
+  it("does not report replacing a markRaw leaf (#4686)", () => {
+    const hits = arm();
+    const leaf = markRaw({ a: 1, b: 2, c: 3 });
+    const [, setStore] = createStore({ item: leaf });
+    setStore(s => {
+      s.item = { a: 1, b: 2, c: 4 };
+    });
+    flush();
+    expect(hits).toEqual([]);
+  });
 });