From 1151f463bf925250cadf341f81fa688f649e8e3e Mon Sep 17 00:00:00 2001
From: Jovi De Croock <decroockjovi@gmail.com>
Date: Wed, 12 Nov 2025 18:35:51 +0100
Subject: [PATCH 1/4] Delay subscribing to a component until its fully mounted

---
 .changeset/nasty-rings-float.md               |   5 +
 packages/react/runtime/src/index.ts           |  19 +
 .../runtime/test/browser/suspense.test.tsx    | 363 ++++++++++++++++++
 3 files changed, 387 insertions(+)
 create mode 100644 .changeset/nasty-rings-float.md

diff --git a/.changeset/nasty-rings-float.md b/.changeset/nasty-rings-float.md
new file mode 100644
index 000000000..c606c5a20
--- /dev/null
+++ b/.changeset/nasty-rings-float.md
@@ -0,0 +1,5 @@
+---
+"@preact/signals-react": major
+---
+
+Delay subscribing to signals until the component is actually mounted
diff --git a/packages/react/runtime/src/index.ts b/packages/react/runtime/src/index.ts
index f7985d6a7..454049d16 100644
--- a/packages/react/runtime/src/index.ts
+++ b/packages/react/runtime/src/index.ts
@@ -94,6 +94,8 @@ export interface EffectStore {
 	getSnapshot(): number;
 	/** startEffect - begin tracking signals used in this component */
 	_start(): void;
+	_subscribers: Array<{ signal: Signal; node: any }>;
+	_sub: typeof Signal.prototype._subscribe;
 	/** finishEffect - stop tracking the signals used in this component */
 	f(): void;
 	[symDispose](): void;
@@ -101,10 +103,15 @@ export interface EffectStore {
 
 let currentStore: EffectStore | undefined;
 
+const realSubscribe = Signal.prototype._subscribe;
 function startComponentEffect(
 	prevStore: EffectStore | undefined,
 	nextStore: EffectStore
 ) {
+	nextStore._sub = Signal.prototype._subscribe;
+	Signal.prototype._subscribe = function (this: Signal, node: any) {
+		nextStore._subscribers.push({ signal: this, node });
+	};
 	const endEffect = nextStore.effect._start();
 	currentStore = nextStore;
 
@@ -116,6 +123,7 @@ function finishComponentEffect(
 	prevStore: EffectStore | undefined,
 	endEffect: () => void
 ) {
+	Signal.prototype._subscribe = this._sub;
 	endEffect();
 	currentStore = prevStore;
 }
@@ -157,6 +165,8 @@ function createEffectStore(_usage: EffectStoreUsage): EffectStore {
 
 	return {
 		_usage,
+		_subscribers: [],
+		_sub: realSubscribe,
 		effect: effectInstance,
 		subscribe(onStoreChange) {
 			onChangeNotifyReact = onStoreChange;
@@ -291,6 +301,8 @@ const noop = () => {};
 
 function createEmptyEffectStore(): EffectStore {
 	return {
+		_subscribers: [],
+		_sub: noop as any,
 		_usage: UNMANAGED,
 		effect: {
 			_sources: undefined,
@@ -354,6 +366,13 @@ export function _useSignalsImplementation(
 	// note: _usage is a constant here, so conditional is okay
 	if (_usage === UNMANAGED) useIsomorphicLayoutEffect(cleanupTrailingStore);
 
+	useIsomorphicLayoutEffect(() => {
+		store._subscribers.forEach(({ signal, node }) => {
+			realSubscribe.call(signal, node);
+		});
+		store._subscribers = [];
+	});
+
 	return store;
 }
 
diff --git a/packages/react/runtime/test/browser/suspense.test.tsx b/packages/react/runtime/test/browser/suspense.test.tsx
index 5142ada70..0cb1be2ea 100644
--- a/packages/react/runtime/test/browser/suspense.test.tsx
+++ b/packages/react/runtime/test/browser/suspense.test.tsx
@@ -161,4 +161,367 @@ describe("Suspense", () => {
 			`<p>1</p><div data-foo="1"><span>lazy</span></div>`
 		);
 	});
+
+	it("should clean up signals after unmount with multiple suspense boundaries", async () => {
+		let watchedCallCount = 0;
+		let unwatchedCallCount = 0;
+
+		// Create a signal with watched/unwatched callbacks to track cleanup
+		const trackedSignal = signal(0, {
+			name: "trackedSignal",
+			watched: function () {
+				watchedCallCount++;
+			},
+			unwatched: function () {
+				unwatchedCallCount++;
+			},
+		});
+
+		let resolveFirstProm!: () => void;
+		let firstPromResolved = false;
+		const firstProm = new Promise(resolve => {
+			resolveFirstProm = () => {
+				firstPromResolved = true;
+				resolve(undefined);
+			};
+		});
+
+		let resolveSecondProm!: () => void;
+		let secondPromResolved = false;
+		const secondProm = new Promise(resolve => {
+			resolveSecondProm = () => {
+				secondPromResolved = true;
+				resolve(undefined);
+			};
+		});
+
+		function FirstSuspendingComponent() {
+			useSignals(0);
+			// Access the signal before any suspense
+			const value = trackedSignal.value;
+			if (!firstPromResolved) throw firstProm;
+			return <div data-first={value}>First</div>;
+		}
+
+		function SecondSuspendingComponent() {
+			useSignals();
+			// Access the signal after first suspense
+			const value = trackedSignal.value;
+			if (!secondPromResolved) throw secondProm;
+			return <div data-second={value}>Second</div>;
+		}
+
+		function RegularComponent() {
+			useSignals();
+			// Access the signal normally
+			return <div data-regular={trackedSignal.value}>Regular</div>;
+		}
+
+		function Parent() {
+			useSignals();
+			// Access the signal at the top level
+			const value = trackedSignal.value;
+			return (
+				<div data-parent={value}>
+					<RegularComponent />
+					<Suspense fallback={<span>Loading first...</span>}>
+						<FirstSuspendingComponent />
+					</Suspense>
+					<Suspense fallback={<span>Loading second...</span>}>
+						<SecondSuspendingComponent />
+					</Suspense>
+				</div>
+			);
+		}
+
+		// Initial render - should trigger watched callback
+		await render(<Parent />);
+		expect(scratch.innerHTML).to.contain("Loading first...");
+		expect(scratch.innerHTML).to.contain("Loading second...");
+		expect(scratch.innerHTML).to.contain("Regular");
+
+		// Signal should be watched by now
+		expect(watchedCallCount).to.be.greaterThan(0);
+		expect(unwatchedCallCount).to.equal(0);
+
+		// Resolve first suspense
+		await act(async () => {
+			resolveFirstProm();
+			await firstProm;
+		});
+
+		expect(scratch.innerHTML).to.contain("First");
+		expect(scratch.innerHTML).to.contain("Loading second...");
+
+		// Resolve second suspense
+		await act(async () => {
+			resolveSecondProm();
+			await secondProm;
+		});
+
+		expect(scratch.innerHTML).to.contain("First");
+		expect(scratch.innerHTML).to.contain("Second");
+		expect(scratch.innerHTML).to.contain("Regular");
+
+		// Update signal to verify it's still being watched
+		await act(async () => {
+			trackedSignal.value = 42;
+		});
+
+		expect(scratch.innerHTML).to.contain('data-parent="42"');
+		expect(scratch.innerHTML).to.contain('data-regular="42"');
+		expect(scratch.innerHTML).to.contain('data-first="42"');
+		expect(scratch.innerHTML).to.contain('data-second="42"');
+
+		// Now unmount the entire tree
+		await act(async () => {
+			root.unmount();
+		});
+
+		expect(scratch.innerHTML).to.equal("");
+
+		// Wait for cleanup to complete
+		await new Promise(resolve => setTimeout(resolve, 10));
+
+		// After unmount, the signal should be unwatched
+		expect(unwatchedCallCount).to.be.greaterThan(0);
+
+		// Verify the signal is no longer being watched by trying to update it
+		// (this won't trigger any re-renders since no components are subscribed)
+		trackedSignal.value = 999;
+
+		// The signal value should have changed but no components should re-render
+		expect(trackedSignal.value).to.equal(999);
+		expect(scratch.innerHTML).to.equal("");
+	});
+
+	it("should clean up signals after unmount with multiple suspense boundaries and use of try catch", async () => {
+		let watchedCallCount = 0;
+		let unwatchedCallCount = 0;
+
+		// Create a signal with watched/unwatched callbacks to track cleanup
+		const trackedSignal = signal(0, {
+			name: "trackedSignal",
+			watched: function () {
+				watchedCallCount++;
+			},
+			unwatched: function () {
+				unwatchedCallCount++;
+			},
+		});
+
+		let resolveFirstProm!: () => void;
+		let firstPromResolved = false;
+		const firstProm = new Promise(resolve => {
+			resolveFirstProm = () => {
+				firstPromResolved = true;
+				resolve(undefined);
+			};
+		});
+
+		let resolveSecondProm!: () => void;
+		let secondPromResolved = false;
+		const secondProm = new Promise(resolve => {
+			resolveSecondProm = () => {
+				secondPromResolved = true;
+				resolve(undefined);
+			};
+		});
+
+		function FirstSuspendingComponent() {
+			const store = useSignals(1);
+			try {
+				// Access the signal before any suspense
+				const value = trackedSignal.value;
+				if (!firstPromResolved) throw firstProm;
+				return <div data-first={value}>First</div>;
+			} finally {
+				store.f();
+			}
+		}
+
+		function SecondSuspendingComponent() {
+			const store = useSignals(1);
+			try {
+				// Access the signal after first suspense
+				const value = trackedSignal.value;
+				if (!secondPromResolved) throw secondProm;
+				return <div data-second={value}>Second</div>;
+			} finally {
+				store.f();
+			}
+		}
+
+		function RegularComponent() {
+			const store = useSignals(1);
+			try {
+				// Access the signal normally
+				return <div data-regular={trackedSignal.value}>Regular</div>;
+			} finally {
+				store.f();
+			}
+		}
+
+		function Parent() {
+			const store = useSignals(1);
+			try {
+				// Access the signal at the top level
+				const value = trackedSignal.value;
+				return (
+					<div data-parent={value}>
+						<RegularComponent />
+						<Suspense fallback={<span>Loading first...</span>}>
+							<FirstSuspendingComponent />
+						</Suspense>
+						<Suspense fallback={<span>Loading second...</span>}>
+							<SecondSuspendingComponent />
+						</Suspense>
+					</div>
+				);
+			} finally {
+				store.f();
+			}
+		}
+
+		// Initial render - should trigger watched callback
+		await render(<Parent />);
+		expect(scratch.innerHTML).to.contain("Loading first...");
+		expect(scratch.innerHTML).to.contain("Loading second...");
+		expect(scratch.innerHTML).to.contain("Regular");
+
+		// Signal should be watched by now
+		expect(watchedCallCount).to.be.greaterThan(0);
+		expect(unwatchedCallCount).to.equal(0);
+
+		// Resolve first suspense
+		await act(async () => {
+			resolveFirstProm();
+			await firstProm;
+		});
+
+		expect(scratch.innerHTML).to.contain("First");
+		expect(scratch.innerHTML).to.contain("Loading second...");
+
+		// Resolve second suspense
+		await act(async () => {
+			resolveSecondProm();
+			await secondProm;
+		});
+
+		expect(scratch.innerHTML).to.contain("First");
+		expect(scratch.innerHTML).to.contain("Second");
+		expect(scratch.innerHTML).to.contain("Regular");
+
+		// Update signal to verify it's still being watched
+		await act(async () => {
+			trackedSignal.value = 42;
+		});
+
+		expect(scratch.innerHTML).to.contain('data-parent="42"');
+		expect(scratch.innerHTML).to.contain('data-regular="42"');
+		expect(scratch.innerHTML).to.contain('data-first="42"');
+		expect(scratch.innerHTML).to.contain('data-second="42"');
+
+		// Now unmount the entire tree
+		await act(async () => {
+			root.unmount();
+		});
+
+		expect(scratch.innerHTML).to.equal("");
+
+		// Wait for cleanup to complete
+		await new Promise(resolve => setTimeout(resolve, 10));
+
+		// After unmount, the signal should be unwatched
+		expect(unwatchedCallCount).to.be.greaterThan(0);
+
+		// Verify the signal is no longer being watched by trying to update it
+		// (this won't trigger any re-renders since no components are subscribed)
+		trackedSignal.value = 999;
+
+		// The signal value should have changed but no components should re-render
+		expect(trackedSignal.value).to.equal(999);
+		expect(scratch.innerHTML).to.equal("");
+	});
+
+	it("should maintain signal watching and clean up after unmount", async () => {
+		let watchedCallCount = 0;
+		let unwatchedCallCount = 0;
+
+		// Create a signal with watched/unwatched callbacks to track cleanup
+		const trackedSignal = signal(0, {
+			name: "trackedSignal",
+			watched: function () {
+				watchedCallCount++;
+			},
+			unwatched: function () {
+				unwatchedCallCount++;
+			},
+		});
+
+		function RegularComponent() {
+			useSignals();
+			// Access the signal normally
+			return <div data-regular={trackedSignal.value}>Regular</div>;
+		}
+
+		function Parent() {
+			useSignals();
+			// Access the signal at the top level
+			const value = trackedSignal.value;
+			return (
+				<div data-parent={value}>
+					<RegularComponent />
+				</div>
+			);
+		}
+
+		// Initial render - should trigger watched callback
+		await render(<Parent />);
+		expect(scratch.innerHTML).to.contain("Regular");
+
+		// Signal should be watched by now
+		expect(watchedCallCount).to.be.greaterThan(0);
+		expect(unwatchedCallCount).to.equal(0);
+
+		// Update signal - should work normally
+		await act(async () => {
+			trackedSignal.value = 10;
+		});
+
+		expect(scratch.innerHTML).to.contain('data-parent="10"');
+		expect(scratch.innerHTML).to.contain('data-regular="10"');
+
+		// Update signal again
+		await act(async () => {
+			trackedSignal.value = 20;
+		});
+
+		expect(scratch.innerHTML).to.contain('data-parent="20"');
+		expect(scratch.innerHTML).to.contain('data-regular="20"');
+
+		// Signal should still be watched (no unwatched calls yet)
+		expect(unwatchedCallCount).to.equal(0);
+
+		// Now unmount the entire tree
+		await act(async () => {
+			root.unmount();
+		});
+
+		expect(scratch.innerHTML).to.equal("");
+
+		// Wait for cleanup to complete
+		await new Promise(resolve => setTimeout(resolve, 10));
+
+		// After unmount, the signal should be unwatched
+		expect(unwatchedCallCount).to.be.greaterThan(0);
+
+		// Verify the signal is no longer being watched by trying to update it
+		// (this won't trigger any re-renders since no components are subscribed)
+		trackedSignal.value = 999;
+
+		// The signal value should have changed but no components should re-render
+		expect(trackedSignal.value).to.equal(999);
+		expect(scratch.innerHTML).to.equal("");
+	});
 });

From 69e6c7ff3f32df8decf55e4cac3add0e370e816e Mon Sep 17 00:00:00 2001
From: Jovi De Croock <decroockjovi@gmail.com>
Date: Wed, 12 Nov 2025 19:58:59 +0100
Subject: [PATCH 2/4] Update packages/react/runtime/src/index.ts

---
 packages/react/runtime/src/index.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/react/runtime/src/index.ts b/packages/react/runtime/src/index.ts
index 454049d16..e609a7397 100644
--- a/packages/react/runtime/src/index.ts
+++ b/packages/react/runtime/src/index.ts
@@ -108,7 +108,7 @@ function startComponentEffect(
 	prevStore: EffectStore | undefined,
 	nextStore: EffectStore
 ) {
-	nextStore._sub = Signal.prototype._subscribe;
+	nextStore._sub = prevStore ? prevStore._sub : Signal.prototype._subscribe;
 	Signal.prototype._subscribe = function (this: Signal, node: any) {
 		nextStore._subscribers.push({ signal: this, node });
 	};

From 54f6443e066d99ac6f1b3da1207ebfdb5a8b17cd Mon Sep 17 00:00:00 2001
From: Jovi De Croock <decroockjovi@gmail.com>
Date: Wed, 12 Nov 2025 20:09:12 +0100
Subject: [PATCH 3/4] Add tests

---
 .../runtime/test/browser/suspense.test.tsx    | 31 ++++++++++++++++---
 .../runtime/test/browser/useSignals.test.tsx  |  3 ++
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/packages/react/runtime/test/browser/suspense.test.tsx b/packages/react/runtime/test/browser/suspense.test.tsx
index 0cb1be2ea..d924255c4 100644
--- a/packages/react/runtime/test/browser/suspense.test.tsx
+++ b/packages/react/runtime/test/browser/suspense.test.tsx
@@ -2,7 +2,7 @@
 globalThis.IS_REACT_ACT_ENVIRONMENT = true;
 
 import { createElement, lazy, useLayoutEffect, Suspense } from "react";
-import { signal } from "@preact/signals-core";
+import { signal, Signal } from "@preact/signals-core";
 import {
 	useComputed,
 	useSignalEffect,
@@ -19,6 +19,7 @@ import {
 describe("Suspense", () => {
 	let scratch: HTMLDivElement;
 	let root: Root;
+	let originalSubscribe: typeof Signal.prototype._subscribe;
 
 	async function render(element: Parameters<Root["render"]>[0]) {
 		await act(() => root.render(element));
@@ -29,6 +30,7 @@ describe("Suspense", () => {
 		document.body.appendChild(scratch);
 		root = await createRoot(scratch);
 		getConsoleErrorSpy().resetHistory();
+		originalSubscribe = Signal.prototype._subscribe;
 	});
 
 	afterEach(async () => {
@@ -40,6 +42,7 @@ describe("Suspense", () => {
 		//
 		// checkConsoleErrorLogs();
 		checkHangingAct();
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
 	});
 
 	it("should handle suspending and unsuspending", async () => {
@@ -122,15 +125,19 @@ describe("Suspense", () => {
 			signal1.value++;
 			signal2.value++;
 		});
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
+
 		await act(async () => {
 			signal1.value--;
 			signal2.value--;
 		});
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
 
 		await act(async () => {
 			resolveMiddleProm();
 			await middleProm;
 		});
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
 
 		expect(scratch.innerHTML).to.be.oneOf([
 			// react 17+
@@ -143,6 +150,7 @@ describe("Suspense", () => {
 			unsuspend();
 			await prom;
 		});
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
 
 		// react 16 uses `style.setProperty()` to clear display value, which leaves an empty style attr in innerHTML.
 		// react 17 does not do this, so we normalize 16 behavior to 17 here.
@@ -157,6 +165,8 @@ describe("Suspense", () => {
 			signal1.value++;
 			signal2.value++;
 		});
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
+
 		expect(scratch.innerHTML).to.equal(
 			`<p>1</p><div data-foo="1"><span>lazy</span></div>`
 		);
@@ -236,6 +246,7 @@ describe("Suspense", () => {
 
 		// Initial render - should trigger watched callback
 		await render(<Parent />);
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
 		expect(scratch.innerHTML).to.contain("Loading first...");
 		expect(scratch.innerHTML).to.contain("Loading second...");
 		expect(scratch.innerHTML).to.contain("Regular");
@@ -249,6 +260,7 @@ describe("Suspense", () => {
 			resolveFirstProm();
 			await firstProm;
 		});
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
 
 		expect(scratch.innerHTML).to.contain("First");
 		expect(scratch.innerHTML).to.contain("Loading second...");
@@ -258,6 +270,7 @@ describe("Suspense", () => {
 			resolveSecondProm();
 			await secondProm;
 		});
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
 
 		expect(scratch.innerHTML).to.contain("First");
 		expect(scratch.innerHTML).to.contain("Second");
@@ -267,6 +280,7 @@ describe("Suspense", () => {
 		await act(async () => {
 			trackedSignal.value = 42;
 		});
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
 
 		expect(scratch.innerHTML).to.contain('data-parent="42"');
 		expect(scratch.innerHTML).to.contain('data-regular="42"');
@@ -281,7 +295,7 @@ describe("Suspense", () => {
 		expect(scratch.innerHTML).to.equal("");
 
 		// Wait for cleanup to complete
-		await new Promise(resolve => setTimeout(resolve, 10));
+		await new Promise(resolve => setTimeout(resolve, 100));
 
 		// After unmount, the signal should be unwatched
 		expect(unwatchedCallCount).to.be.greaterThan(0);
@@ -385,6 +399,7 @@ describe("Suspense", () => {
 
 		// Initial render - should trigger watched callback
 		await render(<Parent />);
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
 		expect(scratch.innerHTML).to.contain("Loading first...");
 		expect(scratch.innerHTML).to.contain("Loading second...");
 		expect(scratch.innerHTML).to.contain("Regular");
@@ -399,6 +414,7 @@ describe("Suspense", () => {
 			await firstProm;
 		});
 
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
 		expect(scratch.innerHTML).to.contain("First");
 		expect(scratch.innerHTML).to.contain("Loading second...");
 
@@ -408,6 +424,7 @@ describe("Suspense", () => {
 			await secondProm;
 		});
 
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
 		expect(scratch.innerHTML).to.contain("First");
 		expect(scratch.innerHTML).to.contain("Second");
 		expect(scratch.innerHTML).to.contain("Regular");
@@ -417,6 +434,7 @@ describe("Suspense", () => {
 			trackedSignal.value = 42;
 		});
 
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
 		expect(scratch.innerHTML).to.contain('data-parent="42"');
 		expect(scratch.innerHTML).to.contain('data-regular="42"');
 		expect(scratch.innerHTML).to.contain('data-first="42"');
@@ -427,10 +445,11 @@ describe("Suspense", () => {
 			root.unmount();
 		});
 
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
 		expect(scratch.innerHTML).to.equal("");
 
 		// Wait for cleanup to complete
-		await new Promise(resolve => setTimeout(resolve, 10));
+		await new Promise(resolve => setTimeout(resolve, 100));
 
 		// After unmount, the signal should be unwatched
 		expect(unwatchedCallCount).to.be.greaterThan(0);
@@ -478,6 +497,7 @@ describe("Suspense", () => {
 
 		// Initial render - should trigger watched callback
 		await render(<Parent />);
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
 		expect(scratch.innerHTML).to.contain("Regular");
 
 		// Signal should be watched by now
@@ -488,6 +508,7 @@ describe("Suspense", () => {
 		await act(async () => {
 			trackedSignal.value = 10;
 		});
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
 
 		expect(scratch.innerHTML).to.contain('data-parent="10"');
 		expect(scratch.innerHTML).to.contain('data-regular="10"');
@@ -497,6 +518,7 @@ describe("Suspense", () => {
 			trackedSignal.value = 20;
 		});
 
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
 		expect(scratch.innerHTML).to.contain('data-parent="20"');
 		expect(scratch.innerHTML).to.contain('data-regular="20"');
 
@@ -508,10 +530,11 @@ describe("Suspense", () => {
 			root.unmount();
 		});
 
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
 		expect(scratch.innerHTML).to.equal("");
 
 		// Wait for cleanup to complete
-		await new Promise(resolve => setTimeout(resolve, 10));
+		await new Promise(resolve => setTimeout(resolve, 100));
 
 		// After unmount, the signal should be unwatched
 		expect(unwatchedCallCount).to.be.greaterThan(0);
diff --git a/packages/react/runtime/test/browser/useSignals.test.tsx b/packages/react/runtime/test/browser/useSignals.test.tsx
index 987faec9c..8457fbdd3 100644
--- a/packages/react/runtime/test/browser/useSignals.test.tsx
+++ b/packages/react/runtime/test/browser/useSignals.test.tsx
@@ -15,6 +15,7 @@ const MANAGED_HOOK = 2;
 describe("useSignals", () => {
 	let scratch: HTMLDivElement;
 	let root: Root;
+	let originalSubscribe: typeof Signal.prototype._subscribe;
 
 	async function render(element: Parameters<Root["render"]>[0]) {
 		await act(() => root.render(element));
@@ -53,6 +54,7 @@ describe("useSignals", () => {
 		document.body.appendChild(scratch);
 		root = await createRoot(scratch);
 		getConsoleErrorSpy().resetHistory();
+		originalSubscribe = Signal.prototype._subscribe;
 	});
 
 	afterEach(async () => {
@@ -64,6 +66,7 @@ describe("useSignals", () => {
 		//
 		// checkConsoleErrorLogs();
 		checkHangingAct();
+		expect(Signal.prototype._subscribe).to.equal(originalSubscribe);
 	});
 
 	it("should rerender components when signals they use change", async () => {

From 2f22abefbc5712ebe179b1b2827e1ea0ed24d335 Mon Sep 17 00:00:00 2001
From: Jovi De Croock <decroockjovi@gmail.com>
Date: Wed, 12 Nov 2025 20:10:28 +0100
Subject: [PATCH 4/4] Ensure we do things correctly in finish effect handoff

---
 packages/react/runtime/src/index.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/react/runtime/src/index.ts b/packages/react/runtime/src/index.ts
index e609a7397..d8317fcd9 100644
--- a/packages/react/runtime/src/index.ts
+++ b/packages/react/runtime/src/index.ts
@@ -108,7 +108,7 @@ function startComponentEffect(
 	prevStore: EffectStore | undefined,
 	nextStore: EffectStore
 ) {
-	nextStore._sub = prevStore ? prevStore._sub : Signal.prototype._subscribe;
+	nextStore._sub = prevStore ? prevStore._sub : realSubscribe;
 	Signal.prototype._subscribe = function (this: Signal, node: any) {
 		nextStore._subscribers.push({ signal: this, node });
 	};
@@ -123,7 +123,7 @@ function finishComponentEffect(
 	prevStore: EffectStore | undefined,
 	endEffect: () => void
 ) {
-	Signal.prototype._subscribe = this._sub;
+	Signal.prototype._subscribe = prevStore ? prevStore._sub : realSubscribe;
 	endEffect();
 	currentStore = prevStore;
 }