working?

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

@@ -439,7 +439,16 @@ export function client_component(source, analysis, options) {
 
 	if (options.dev && state.options.filename) {
 		body.unshift(b.stmt(b.call(b.id('$.push_module'), b.literal(state.options.filename))));
-		body.push(b.stmt(b.call(b.id('$.pop_module'), b.literal(state.options.filename))));
+		body.push(
+			b.stmt(
+				b.assignment(
+					'=',
+					b.member(b.id(analysis.name), b.id('filename')),
+					b.literal(state.options.filename)
+				)
+			)
+		);
+		body.push(b.stmt(b.call(b.id('$.pop_module'))));
 	}
 
 	return {

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

@@ -763,6 +763,8 @@ function serialize_inline_component(node, component_name, context) {
 	/** @type {import('estree').Identifier | import('estree').MemberExpression | null} */
 	let bind_this = null;
 
+	const binding_initializers = [];
+
 	/**
 	 * If this component has a slot property, it is a named slot within another component. In this case
 	 * the slot scope applies to the component itself, too, and not just its children.
@@ -850,14 +852,21 @@ function serialize_inline_component(node, component_name, context) {
 			if (attribute.name === 'this') {
 				bind_this = attribute.expression;
 			} else {
-				push_prop(
-					b.get(attribute.name, [
-						b.return(
-							/** @type {import('estree').Expression} */ (context.visit(attribute.expression))
+				const expression = /** @type {import('estree').Expression} */ (
+					context.visit(attribute.expression)
+				);
+
+				binding_initializers.push(
+					b.stmt(
+						b.call(
+							b.id('$.pre_effect'),
+							b.thunk(b.call(b.id('$.add_owner'), expression, b.id(component_name)))
 						)
-					])
+					)
 				);
 
+				push_prop(b.get(attribute.name, [b.return(expression)]));
+
 				const assignment = b.assignment('=', attribute.expression, b.id('$$value'));
 				push_prop(
 					b.set(attribute.name, [
@@ -997,14 +1006,11 @@ function serialize_inline_component(node, component_name, context) {
 			);
 	}
 
-	/** @type {import('estree').Statement} */
-	let statement = b.stmt(fn(context.state.node));
+	const statements = [...snippet_declarations, ...binding_initializers];
 
-	if (snippet_declarations.length > 0) {
-		statement = b.block([...snippet_declarations, statement]);
-	}
+	statements.push(b.stmt(fn(context.state.node)));
 
-	return statement;
+	return statements.length > 1 ? b.block(statements) : statements[0];
 }
 
 /**

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

@@ -1,5 +1,7 @@
 /** @typedef {{ file: string, line: number, column: number }} Location */
 
+import { deep_read, set_current_owner, set_current_owner_override, untrack } from './runtime.js';
+
 /** @type {Record<string, Array<{ start: Location, end: Location, filename: string }>>} */
 const boundaries = {};
 
@@ -61,10 +63,7 @@ export function push_module(filename) {
 	}
 }
 
-/**
- * @param {string} filename
- */
-export function pop_module(filename) {
+export function pop_module() {
 	const end = get_stack()?.[1];
 
 	if (end) {
@@ -72,3 +71,16 @@ export function pop_module(filename) {
 		boundaries[end.file].at(-1).end = end;
 	}
 }
+
+/**
+ *
+ * @param {any} object
+ * @param {any} owner
+ */
+export function add_owner(object, owner) {
+	untrack(() => {
+		set_current_owner_override(owner.filename);
+		deep_read(object);
+		set_current_owner_override(null);
+	});
+}

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

@@ -8,7 +8,10 @@ import {
 	updating_derived,
 	UNINITIALIZED,
 	mutable_source,
-	batch_inspect
+	batch_inspect,
+	set_current_owner,
+	current_component_context,
+	current_owner
 } from './runtime.js';
 import {
 	array_prototype,
@@ -54,7 +57,7 @@ export function proxy(value, immutable = true) {
 					i: immutable,
 					p: proxy,
 					t: value,
-					o: DEV ? get_module() : ''
+					o: DEV && (current_owner ?? current_component_context?.f)
 				}),
 				writable: true,
 				enumerable: false
@@ -178,12 +181,18 @@ const state_proxy_handler = {
 			(effect_active() || updating_derived) &&
 			(!(prop in target) || get_descriptor(target, prop)?.writable)
 		) {
+			console.log('setting current owner', metadata.o);
+			const previous_owner = current_owner;
+			if (!current_owner) set_current_owner(metadata.o);
 			s = (metadata.i ? source : mutable_source)(proxy(target[prop], metadata.i));
+			set_current_owner(previous_owner);
 			metadata.s.set(prop, s);
 		}
 
 		if (s !== undefined) {
+			// set_current_owner(metadata.o);
 			const value = get(s);
+			// set_current_owner(null);
 			return value === UNINITIALIZED ? undefined : value;
 		}
 
@@ -251,13 +260,6 @@ const state_proxy_handler = {
 		// @ts-ignore
 		target[prop] = value;
 
-		if (DEV) {
-			const site = get_module();
-			if (site !== metadata.o) {
-				console.error(`mutating state outside the component where it was created: ${site}`);
-			}
-		}
-
 		if (not_has) {
 			// If we have mutated an array directly, we might need to
 			// signal that length has also changed. Do it before updating metadata

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

@@ -19,6 +19,7 @@ import {
 } from '../../constants.js';
 import { STATE_SYMBOL, unstate } from './proxy.js';
 import { EACH_BLOCK, IF_BLOCK } from './block.js';
+import { get_module } from './dev.js';
 
 export const SOURCE = 1;
 export const DERIVED = 1 << 1;
@@ -106,6 +107,26 @@ export let current_component_context = null;
 
 export let updating_derived = false;
 
+/** @type {string | null} */
+export let current_owner = null;
+
+/**
+ * @param {string | null} owner
+ */
+export function set_current_owner(owner) {
+	current_owner = owner;
+}
+
+/** @type {string | null} */
+export let current_owner_override = null;
+
+/**
+ * @param {string | null} owner
+ */
+export function set_current_owner_override(owner) {
+	current_owner_override = owner;
+}
+
 /**
  * @param {null | import('./types.js').ComponentContext} context
  * @returns {boolean}
@@ -913,11 +934,17 @@ export function unsubscribe_on_destroy(stores) {
  * @returns {V}
  */
 export function get(signal) {
-	// @ts-expect-error
-	if (DEV && signal.inspect && inspect_fn) {
-		/** @type {import('./types.js').SignalDebug} */ (signal).inspect.add(inspect_fn);
+	if (DEV) {
+		if (signal.o && (current_owner_override || current_owner)) {
+			signal.o.add(current_owner_override || current_owner);
+		}
+
 		// @ts-expect-error
-		inspect_captured_signals.push(signal);
+		if (signal.inspect && inspect_fn) {
+			/** @type {import('./types.js').SignalDebug} */ (signal).inspect.add(inspect_fn);
+			// @ts-expect-error
+			inspect_captured_signals.push(signal);
+		}
 	}
 
 	const flags = signal.f;
@@ -983,6 +1010,13 @@ export function get(signal) {
  * @returns {V}
  */
 export function set(signal, value) {
+	if (DEV && 'o' in signal) {
+		const site = get_module();
+		if (site && !signal.o.has(site)) {
+			console.error(`mutating state outside the component where it was created: ${site}`);
+		}
+	}
+
 	set_signal_value(signal, value);
 	return value;
 }
@@ -1295,6 +1329,13 @@ export function source(initial_value) {
  * @param {import('./types.js').Signal} signal
  */
 function bind_signal_to_component_context(signal) {
+	if (DEV) {
+		const owner = current_owner ?? current_component_context?.f;
+		if (owner) {
+			(signal.o ??= new Set()).add(owner);
+		}
+	}
+
 	if (current_component_context === null || !current_component_context.r) return;
 
 	const signals = current_component_context.d;
@@ -1858,7 +1899,6 @@ function on_destroy(fn) {
  */
 export function push(props, runes = false) {
 	current_component_context = {
-		// accessors
 		a: null,
 		// context
 		c: null,
@@ -1875,7 +1915,9 @@ export function push(props, runes = false) {
 		// runes
 		r: runes,
 		// update_callbacks
-		u: null
+		u: null,
+		// filename
+		f: (DEV && get_module()) || ''
 	};
 }
 
@@ -1956,7 +1998,7 @@ export function init() {
  * @param {Set<any>} visited
  * @returns {void}
  */
-function deep_read(value, visited = new Set()) {
+export function deep_read(value, visited = new Set()) {
 	if (typeof value === 'object' && value !== null && !visited.has(value)) {
 		visited.add(value);
 		for (let key in value) {

packages/svelte/src/internal/client/types.d.ts

@@ -61,6 +61,8 @@ export type ComponentContext = {
 		/** onMount callbacks */
 		m: Array<() => any>;
 	};
+	/** filename */
+	f: string;
 };
 
 // We keep two shapes rather than a single monomorphic shape to improve the memory usage.
@@ -77,6 +79,8 @@ export type SourceSignal<V = unknown> = {
 	f: SignalFlags;
 	/** value: The latest value for this signal */
 	v: V;
+	/** owners: The components that can write to this signal */
+	o: Set<string>;
 };
 
 export type SourceSignalDebug = {