fix: prevent false positive ownership warning when reassigning state

When a proxy is reassigned, we call `$.proxy` again. There are cases where there's a component context set but the reassignment actually happens for variable that is ownerless within shared state or somewhere else. In that case we get false positives right now. The fix is to pass the previous value in to copy over the owners from it.

Fixes #11525

Author: dummdidumm

.changeset/modern-apricots-promise.md

@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+fix: prevent false positive ownership warning when reassigning state

packages/svelte/src/compiler/phases/3-transform/client/utils.js

@@ -203,7 +203,7 @@ export function serialize_set_binding(node, context, fallback, options) {
 							assignment.right =
 								private_state.kind === 'frozen_state'
 									? b.call('$.freeze', value)
-									: b.call('$.proxy', value);
+									: b.call('$.proxy', value, b.true, b.null, b.member(b.this, private_state.id));
 							return assignment;
 						}
 					}
@@ -216,7 +216,7 @@ export function serialize_set_binding(node, context, fallback, options) {
 							should_proxy_or_freeze(value, context.state.scope)
 							? private_state.kind === 'frozen_state'
 								? b.call('$.freeze', value)
-								: b.call('$.proxy', value)
+								: b.call('$.proxy', value, b.true, b.null, b.member(b.this, private_state.id))
 							: value
 					);
 				}
@@ -240,7 +240,7 @@ export function serialize_set_binding(node, context, fallback, options) {
 					assignment.right =
 						public_state.kind === 'frozen_state'
 							? b.call('$.freeze', value)
-							: b.call('$.proxy', value);
+							: b.call('$.proxy', value, b.true, b.null, b.member(b.this, public_state.id));
 					return assignment;
 				}
 			}
@@ -305,7 +305,7 @@ export function serialize_set_binding(node, context, fallback, options) {
 						context.state.analysis.runes &&
 							!options?.skip_proxy_and_freeze &&
 							should_proxy_or_freeze(value, context.state.scope)
-							? b.call('$.proxy', value)
+							? b.call('$.proxy', value, b.true, b.null, b.id(left_name))
 							: value
 					);
 				} else if (binding.kind === 'frozen_state') {

packages/svelte/src/compiler/phases/3-transform/client/visitors/javascript-runes.js

@@ -139,7 +139,15 @@ export const javascript_visitors_runes = {
 									'set',
 									definition.key,
 									[value],
-									[b.stmt(b.call('$.set', member, b.call('$.proxy', value)))]
+									[
+										b.stmt(
+											b.call(
+												'$.set',
+												member,
+												b.call('$.proxy', value, b.true, b.null, b.member(b.this, field.id))
+											)
+										)
+									]
 								)
 							);
 						}

packages/svelte/src/compiler/utils/builders.js

@@ -99,7 +99,7 @@ export function labeled(name, body) {
 
 /**
  * @param {string | import('estree').Expression} callee
- * @param {...(import('estree').Expression | import('estree').SpreadElement | false | undefined)} args
+ * @param {...(import('estree').Expression | import('estree').SpreadElement | import('estree').PrivateIdentifier | false | undefined)} args
  * @returns {import('estree').CallExpression}
  */
 export function call(callee, ...args) {
@@ -469,6 +469,7 @@ export function do_while(test, body) {
 
 const true_instance = literal(true);
 const false_instance = literal(false);
+const null_instane = literal(null);
 
 /** @type {import('estree').DebuggerStatement} */
 const debugger_builder = {
@@ -630,6 +631,7 @@ export {
 	return_builder as return,
 	if_builder as if,
 	this_instance as this,
+	null_instane as null,
 	debugger_builder as debugger
 };
 

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

@@ -27,9 +27,10 @@ import * as e from './errors.js';
  * @param {T} value
  * @param {boolean} [immutable]
  * @param {import('#client').ProxyMetadata | null} [parent]
+ * @param {import('#client').Source<T>} [prev]
  * @returns {import('#client').ProxyStateObject<T> | T}
  */
-export function proxy(value, immutable = true, parent = null) {
+export function proxy(value, immutable = true, parent = null, prev) {
 	if (typeof value === 'object' && value != null && !is_frozen(value)) {
 		// If we have an existing proxy, return it...
 		if (STATE_SYMBOL in value) {
@@ -70,14 +71,21 @@ export function proxy(value, immutable = true, parent = null) {
 			if (DEV) {
 				// @ts-expect-error
 				value[STATE_SYMBOL].parent = parent;
-
 				// @ts-expect-error
-				value[STATE_SYMBOL].owners =
-					parent === null
-						? current_component_context !== null
-							? new Set([current_component_context.function])
-							: null
-						: new Set();
+				prev = prev?.v?.[STATE_SYMBOL];
+
+				if (prev) {
+					// @ts-expect-error reuse owners from previous state; necessary because creation could happen in the wrong context
+					value[STATE_SYMBOL].owners = prev.owners ? new Set(prev.owners) : null;
+				} else {
+					// @ts-expect-error
+					value[STATE_SYMBOL].owners =
+						parent === null
+							? current_component_context !== null
+								? new Set([current_component_context.function])
+								: null
+							: new Set();
+				}
 			}
 
 			return proxy;