make internal sources ownerless (#13013)

* make internal sources ownerless

* WIP

* WIP

* WIP

* same for mutable_state

* oops

* DRY

* unrelated

* changeset

* fix

Author: Rich-Harris

.changeset/six-moons-invent.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: make internal sources ownerless

benchmarking/benchmarks/kairo/kairo_avoidable.js

@@ -3,7 +3,7 @@ import * as $ from '../../../packages/svelte/src/internal/client/index.js';
 import { busy } from './util.js';
 
 function setup() {
-	let head = $.source(0);
+	let head = $.state(0);
 	let computed1 = $.derived(() => $.get(head));
 	let computed2 = $.derived(() => ($.get(computed1), 0));
 	let computed3 = $.derived(() => (busy(), $.get(computed2) + 1)); // heavy computation

benchmarking/benchmarks/kairo/kairo_broad.js

@@ -2,7 +2,7 @@ import { assert, fastest_test } from '../../utils.js';
 import * as $ from '../../../packages/svelte/src/internal/client/index.js';
 
 function setup() {
-	let head = $.source(0);
+	let head = $.state(0);
 	let last = head;
 	let counter = 0;
 

benchmarking/benchmarks/kairo/kairo_deep.js

@@ -5,7 +5,7 @@ let len = 50;
 const iter = 50;
 
 function setup() {
-	let head = $.source(0);
+	let head = $.state(0);
 	let current = head;
 	for (let i = 0; i < len; i++) {
 		let c = current;

benchmarking/benchmarks/kairo/kairo_diamond.js

@@ -4,7 +4,7 @@ import * as $ from '../../../packages/svelte/src/internal/client/index.js';
 let width = 5;
 
 function setup() {
-	let head = $.source(0);
+	let head = $.state(0);
 	let current = [];
 	for (let i = 0; i < width; i++) {
 		current.push(

benchmarking/benchmarks/kairo/kairo_mux.js

@@ -2,7 +2,7 @@ import { assert, fastest_test } from '../../utils.js';
 import * as $ from '../../../packages/svelte/src/internal/client/index.js';
 
 function setup() {
-	let heads = new Array(100).fill(null).map((_) => $.source(0));
+	let heads = new Array(100).fill(null).map((_) => $.state(0));
 	const mux = $.derived(() => {
 		return Object.fromEntries(heads.map((h) => $.get(h)).entries());
 	});

benchmarking/benchmarks/kairo/kairo_repeated.js

@@ -4,7 +4,7 @@ import * as $ from '../../../packages/svelte/src/internal/client/index.js';
 let size = 30;
 
 function setup() {
-	let head = $.source(0);
+	let head = $.state(0);
 	let current = $.derived(() => {
 		let result = 0;
 		for (let i = 0; i < size; i++) {

benchmarking/benchmarks/kairo/kairo_triangle.js

@@ -11,7 +11,7 @@ function count(number) {
 }
 
 function setup() {
-	let head = $.source(0);
+	let head = $.state(0);
 	let current = head;
 	let list = [];
 	for (let i = 0; i < width; i++) {

benchmarking/benchmarks/kairo/kairo_unstable.js

@@ -2,7 +2,7 @@ import { assert, fastest_test } from '../../utils.js';
 import * as $ from '../../../packages/svelte/src/internal/client/index.js';
 
 function setup() {
-	let head = $.source(0);
+	let head = $.state(0);
 	const double = $.derived(() => $.get(head) * 2);
 	const inverse = $.derived(() => -$.get(head));
 	let current = $.derived(() => {

benchmarking/benchmarks/mol_bench.js

@@ -20,8 +20,8 @@ const numbers = Array.from({ length: 5 }, (_, i) => i);
 
 function setup() {
 	let res = [];
-	const A = $.source(0);
-	const B = $.source(0);
+	const A = $.state(0);
+	const B = $.state(0);
 	const C = $.derived(() => ($.get(A) % 2) + ($.get(B) % 2));
 	const D = $.derived(() => numbers.map((i) => i + ($.get(A) % 2) - ($.get(B) % 2)));
 	D.equals = function (/** @type {number[]} */ l) {

benchmarking/benchmarks/sbench.js

@@ -9,7 +9,7 @@ const COUNT = 1e5;
  */
 function create_data_signals(n, sources) {
 	for (let i = 0; i < n; i++) {
-		sources[i] = $.source(i);
+		sources[i] = $.state(i);
 	}
 	return sources;
 }

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

@@ -207,7 +207,7 @@ export function client_component(analysis, options) {
 
 	for (const [name, binding] of analysis.instance.scope.declarations) {
 		if (binding.kind === 'legacy_reactive') {
-			legacy_reactive_declarations.push(b.const(name, b.call('$.mutable_source')));
+			legacy_reactive_declarations.push(b.const(name, b.call('$.mutable_state')));
 		}
 		if (binding.kind === 'store_sub') {
 			if (store_setup.length === 0) {

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

@@ -113,17 +113,17 @@ export function ClassBody(node, context) {
 					value =
 						field.kind === 'state'
 							? b.call(
-									'$.source',
+									'$.state',
 									should_proxy(init, context.state.scope) ? b.call('$.proxy', init) : init
 								)
 							: field.kind === 'raw_state'
-								? b.call('$.source', init)
+								? b.call('$.state', init)
 								: field.kind === 'derived_by'
 									? b.call('$.derived', init)
 									: b.call('$.derived', b.thunk(init));
 				} else {
 					// if no arguments, we know it's state as `$derived()` is a compile error
-					value = b.call('$.source');
+					value = b.call('$.state');
 				}
 
 				if (is_private) {

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

@@ -126,7 +126,7 @@ export function VariableDeclaration(node, context) {
 						value = b.call('$.proxy', value);
 					}
 					if (is_state_source(binding, context.state.analysis)) {
-						value = b.call('$.source', value);
+						value = b.call('$.state', value);
 					}
 					return value;
 				};
@@ -291,7 +291,7 @@ export function VariableDeclaration(node, context) {
  */
 function create_state_declarators(declarator, scope, value) {
 	if (declarator.id.type === 'Identifier') {
-		return [b.declarator(declarator.id, b.call('$.mutable_source', value))];
+		return [b.declarator(declarator.id, b.call('$.mutable_state', value))];
 	}
 
 	const tmp = scope.generate('tmp');
@@ -303,7 +303,7 @@ function create_state_declarators(declarator, scope, value) {
 			const binding = scope.get(/** @type {Identifier} */ (path.node).name);
 			return b.declarator(
 				path.node,
-				binding?.kind === 'state' ? b.call('$.mutable_source', value) : value
+				binding?.kind === 'state' ? b.call('$.mutable_state', value) : value
 			);
 		})
 	];

packages/svelte/src/internal/client/dom/blocks/await.js

@@ -52,10 +52,8 @@ export function await_block(node, get_input, pending_fn, then_fn, catch_fn) {
 	/** @type {Effect | null} */
 	var catch_effect;
 
-	var input_source = runes
-		? source(/** @type {V} */ (undefined))
-		: mutable_source(/** @type {V} */ (undefined));
-	var error_source = runes ? source(undefined) : mutable_source(undefined);
+	var input_source = (runes ? source : mutable_source)(/** @type {V} */ (undefined));
+	var error_source = (runes ? source : mutable_source)(undefined);
 	var resolved = false;
 
 	/**

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

@@ -105,7 +105,7 @@ export {
 	user_effect,
 	user_pre_effect
 } from './reactivity/effects.js';
-export { mutable_source, mutate, source, set } from './reactivity/sources.js';
+export { mutable_state, mutate, set, state } from './reactivity/sources.js';
 export {
 	prop,
 	rest_props,

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

@@ -118,7 +118,7 @@ export function proxy(value, parent = null, prev) {
 
 			// create a source, but only if it's an own property and not a prototype property
 			if (s === undefined && (!exists || get_descriptor(target, prop)?.writable)) {
-				s = source(proxy(exists ? target[prop] : UNINITIALIZED, metadata), null);
+				s = source(proxy(exists ? target[prop] : UNINITIALIZED, metadata));
 				sources.set(prop, s);
 			}
 
@@ -170,7 +170,7 @@ export function proxy(value, parent = null, prev) {
 				(current_effect !== null && (!has || get_descriptor(target, prop)?.writable))
 			) {
 				if (s === undefined) {
-					s = source(has ? proxy(target[prop], metadata) : UNINITIALIZED, null);
+					s = source(has ? proxy(target[prop], metadata) : UNINITIALIZED);
 					sources.set(prop, s);
 				}
 

packages/svelte/src/internal/client/reactivity/sources.js

@@ -34,39 +34,34 @@ let inspect_effects = new Set();
 /**
  * @template V
  * @param {V} v
- * @param {Reaction | null} [owner]
  * @returns {Source<V>}
  */
-/*#__NO_SIDE_EFFECTS__*/
-export function source(v, owner = current_reaction) {
-	var source = {
+export function source(v) {
+	return {
 		f: 0, // TODO ideally we could skip this altogether, but it causes type errors
 		v,
 		reactions: null,
 		equals,
 		version: 0
 	};
+}
 
-	if (owner !== null && (owner.f & DERIVED) !== 0) {
-		if (derived_sources === null) {
-			set_derived_sources([source]);
-		} else {
-			derived_sources.push(source);
-		}
-	}
-
-	return source;
+/**
+ * @template V
+ * @param {V} v
+ */
+export function state(v) {
+	return push_derived_source(source(v));
 }
 
 /**
  * @template V
  * @param {V} initial_value
- * @param {Reaction | null} [owner]
  * @returns {Source<V>}
  */
 /*#__NO_SIDE_EFFECTS__*/
-export function mutable_source(initial_value, owner) {
-	const s = source(initial_value, owner);
+export function mutable_source(initial_value) {
+	const s = source(initial_value);
 	s.equals = safe_equals;
 
 	// bind the signal to the component context, in case we need to
@@ -78,6 +73,32 @@ export function mutable_source(initial_value, owner) {
 	return s;
 }
 
+/**
+ * @template V
+ * @param {V} v
+ * @returns {Source<V>}
+ */
+export function mutable_state(v) {
+	return push_derived_source(mutable_source(v));
+}
+
+/**
+ * @template V
+ * @param {Source<V>} source
+ */
+/*#__NO_SIDE_EFFECTS__*/
+function push_derived_source(source) {
+	if (current_reaction !== null && (current_reaction.f & DERIVED) !== 0) {
+		if (derived_sources === null) {
+			set_derived_sources([source]);
+		} else {
+			derived_sources.push(source);
+		}
+	}
+
+	return source;
+}
+
 /**
  * @template V
  * @param {Value<V>} source

packages/svelte/src/internal/client/reactivity/store.js

@@ -19,7 +19,7 @@ import { mutable_source, set } from './sources.js';
 export function store_get(store, store_name, stores) {
 	const entry = (stores[store_name] ??= {
 		store: null,
-		source: mutable_source(undefined, null),
+		source: mutable_source(undefined),
 		unsubscribe: noop
 	});