feat: more efficient ownership widening

packages/svelte/src/internal/client/dev/ownership.js

@@ -1,6 +1,7 @@
 /** @typedef {{ file: string, line: number, column: number }} Location */
 
 import { STATE_SYMBOL } from '../constants.js';
+import { unstate } from '../proxy.js';
 import { untrack } from '../runtime.js';
 import { get_descriptors } from '../utils.js';
 
@@ -92,88 +93,44 @@ export function mark_module_end() {
 	}
 }
 
-let add_owner_visited = new Set();
-
 /**
  *
  * @param {any} object
  * @param {any} owner
  */
 export function add_owner(object, owner) {
-	// Needed because ownership addition can invoke getters on a proxy,
-	// calling add_owner anew, so just keeping the set as part of
-	// add_owner_to_object would not be enough.
-	const prev = add_owner_visited;
-	try {
-		add_owner_visited = new Set(add_owner_visited);
-		untrack(() => {
-			add_owner_to_object(object, owner, add_owner_visited);
-		});
-	} finally {
-		add_owner_visited = prev;
-	}
+	untrack(() => {
+		var previous_owner = current_owner;
+		current_owner = owner;
+		add_owner_to_object(object);
+		current_owner = previous_owner;
+	});
 }
 
-/**
- * @param {any} object
- * @param {Function} owner
- * @param {Set<any>} visited
- */
-function add_owner_to_object(object, owner, visited) {
-	if (visited.has(object)) return;
-	visited.add(object);
-
-	if (object?.[STATE_SYMBOL]?.o && !object[STATE_SYMBOL].o.has(owner)) {
-		object[STATE_SYMBOL].o.add(owner);
-	}
-	// Not inside previous if-block; there could be normal objects in-between
-	traverse_for_owners(object, (nested) => add_owner_to_object(nested, owner, visited));
-}
-
-let strip_owner_visited = new Set();
+/** @type {any} */
+export var current_owner = null;
 
 /**
  * @param {any} object
+ * @param {Set<any>} [seen]
  */
-export function strip_owner(object) {
-	// Needed because ownership stripping can invoke getters on a proxy,
-	// calling strip_owner anew, so just keeping the set as part of
-	// strip_owner_from_object would not be enough.
-	const prev = strip_owner_visited;
-	try {
-		untrack(() => {
-			strip_owner_from_object(object, strip_owner_visited);
-		});
-	} finally {
-		strip_owner_visited = prev;
+function add_owner_to_object(object, seen = new Set()) {
+	if (seen.has(object) || typeof object !== 'object' || object === null) {
+		return;
 	}
-}
-
-/**
- * @param {any} object
- * @param {Set<any>} visited
- */
-function strip_owner_from_object(object, visited) {
-	if (visited.has(object)) return;
-	visited.add(object);
 
 	if (object?.[STATE_SYMBOL]?.o) {
-		object[STATE_SYMBOL].o = null;
-	}
-	// Not inside previous if-block; there could be normal objects in-between
-	traverse_for_owners(object, (nested) => strip_owner_from_object(nested, visited));
-}
-
-/**
- * @param {any} object
- * @param {(obj: any) => void} cb
- */
-function traverse_for_owners(object, cb) {
-	if (typeof object === 'object' && object !== null && !(object instanceof EventTarget)) {
-		for (const key in object) {
-			cb(object[key]);
+		object[STATE_SYMBOL].o.add(current_owner);
+	} else {
+		seen.add(object);
+
+		for (let key in object) {
+			try {
+				add_owner_to_object(object[key], seen);
+			} catch (e) {
+				// continue
+			}
 		}
-		// deal with state on classes
 		const proto = Object.getPrototypeOf(object);
 		if (
 			proto !== Object.prototype &&
@@ -187,7 +144,7 @@ function traverse_for_owners(object, cb) {
 				const get = descriptors[key].get;
 				if (get) {
 					try {
-						cb(object[key]);
+						get.call(object);
 					} catch (e) {
 						// continue
 					}
@@ -197,6 +154,28 @@ function traverse_for_owners(object, cb) {
 	}
 }
 
+/**
+ * @param {any} object
+ */
+export function strip_owner(object) {
+	untrack(() => {
+		strip_owner_from_object(object);
+	});
+}
+
+/**
+ * @param {any} object
+ */
+function strip_owner_from_object(object) {
+	if (object?.[STATE_SYMBOL]?.o) {
+		object[STATE_SYMBOL].o = null;
+
+		for (const key in object) {
+			strip_owner(object[key]);
+		}
+	}
+}
+
 /**
  * @param {Set<Function>} owners
  */

packages/svelte/src/internal/client/runtime.js

@@ -25,7 +25,7 @@ import {
 	ROOT_EFFECT
 } from './constants.js';
 import { flush_tasks } from './dom/task.js';
-import { add_owner } from './dev/ownership.js';
+import { add_owner, current_owner } from './dev/ownership.js';
 import { mutate, set, source } from './reactivity/sources.js';
 import { update_derived } from './reactivity/deriveds.js';
 
@@ -758,6 +758,10 @@ export function get(signal) {
 		}
 	}
 
+	if (current_owner !== null && signal.v?.[STATE_SYMBOL]?.o) {
+		signal.v[STATE_SYMBOL].o.add(current_owner);
+	}
+
 	return signal.v;
 }
 

packages/svelte/src/internal/client/utils.js

@@ -47,3 +47,15 @@ export function map_get(map, key) {
 export function is_function(thing) {
 	return typeof thing === 'function';
 }
+
+/** @param {any} object */
+export function is_exotic_object(object) {
+	const proto = Object.getPrototypeOf(object);
+	return (
+		proto !== Object.prototype &&
+		proto !== Array.prototype &&
+		proto !== Map.prototype &&
+		proto !== Set.prototype &&
+		proto !== Date.prototype
+	);
+}