chore: remove stack-based module boundaries (#15711)

Author: Rich-Harris

documentation/docs/98-reference/.generated/client-errors.md

@@ -21,7 +21,7 @@ A component is attempting to bind to a non-bindable property `%key%` belonging t
 ### component_api_changed
 
 ```
-%parent% called `%method%` on an instance of %component%, which is no longer valid in Svelte 5
+Calling `%method%` on a component instance (of %component%) is no longer valid in Svelte 5
 ```
 
 See the [migration guide](/docs/svelte/v5-migration-guide#Components-are-no-longer-classes) for more information.

packages/svelte/messages/client-errors/errors.md

@@ -12,7 +12,7 @@
 
 ## component_api_changed
 
-> %parent% called `%method%` on an instance of %component%, which is no longer valid in Svelte 5
+> Calling `%method%` on a component instance (of %component%) is no longer valid in Svelte 5
 
 See the [migration guide](/docs/svelte/v5-migration-guide#Components-are-no-longer-classes) for more information.
 

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

@@ -536,9 +536,6 @@ export function client_component(analysis, options) {
 				b.assignment('=', b.member(b.id(analysis.name), '$.FILENAME', true), b.literal(filename))
 			)
 		);
-
-		body.unshift(b.stmt(b.call(b.id('$.mark_module_start'))));
-		body.push(b.stmt(b.call(b.id('$.mark_module_end'), b.id(analysis.name))));
 	}
 
 	if (!analysis.runes) {

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

@@ -1,7 +1,6 @@
 import * as e from '../errors.js';
 import { component_context } from '../context.js';
 import { FILENAME } from '../../../constants.js';
-import { get_component } from './ownership.js';
 
 /** @param {Function & { [FILENAME]: string }} target */
 export function check_target(target) {
@@ -15,9 +14,7 @@ export function legacy_api() {
 
 	/** @param {string} method */
 	function error(method) {
-		// @ts-expect-error
-		const parent = get_component()?.[FILENAME] ?? 'Something';
-		e.component_api_changed(parent, method, component[FILENAME]);
+		e.component_api_changed(method, component[FILENAME]);
 	}
 
 	return {

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

@@ -7,103 +7,6 @@ import { component_context } from '../context.js';
 import * as w from '../warnings.js';
 import { sanitize_location } from '../../../utils.js';
 
-/** @type {Record<string, Array<{ start: Location, end: Location, component: Function }>>} */
-const boundaries = {};
-
-const chrome_pattern = /at (?:.+ \()?(.+):(\d+):(\d+)\)?$/;
-const firefox_pattern = /@(.+):(\d+):(\d+)$/;
-
-function get_stack() {
-	const stack = new Error().stack;
-	if (!stack) return null;
-
-	const entries = [];
-
-	for (const line of stack.split('\n')) {
-		let match = chrome_pattern.exec(line) ?? firefox_pattern.exec(line);
-
-		if (match) {
-			entries.push({
-				file: match[1],
-				line: +match[2],
-				column: +match[3]
-			});
-		}
-	}
-
-	return entries;
-}
-
-/**
- * Determines which `.svelte` component is responsible for a given state change
- * @returns {Function | null}
- */
-export function get_component() {
-	// first 4 lines are svelte internals; adjust this number if we change the internal call stack
-	const stack = get_stack()?.slice(4);
-	if (!stack) return null;
-
-	for (let i = 0; i < stack.length; i++) {
-		const entry = stack[i];
-		const modules = boundaries[entry.file];
-		if (!modules) {
-			// If the first entry is not a component, that means the modification very likely happened
-			// within a .svelte.js file, possibly triggered by a component. Since these files are not part
-			// of the bondaries/component context heuristic, we need to bail in this case, else we would
-			// have false positives when the .svelte.ts file provides a state creator function, encapsulating
-			// the state and its mutations, and is being called from a component other than the one who
-			// called the state creator function.
-			if (i === 0) return null;
-			continue;
-		}
-
-		for (const module of modules) {
-			if (module.end == null) {
-				return null;
-			}
-			if (module.start.line < entry.line && module.end.line > entry.line) {
-				return module.component;
-			}
-		}
-	}
-
-	return null;
-}
-
-/**
- * Together with `mark_module_end`, this function establishes the boundaries of a `.svelte` file,
- * such that subsequent calls to `get_component` can tell us which component is responsible
- * for a given state change
- */
-export function mark_module_start() {
-	const start = get_stack()?.[2];
-
-	if (start) {
-		(boundaries[start.file] ??= []).push({
-			start,
-			// @ts-expect-error
-			end: null,
-			// @ts-expect-error we add the component at the end, since HMR will overwrite the function
-			component: null
-		});
-	}
-}
-
-/**
- * @param {Function} component
- */
-export function mark_module_end(component) {
-	const end = get_stack()?.[2];
-
-	if (end) {
-		const boundaries_file = boundaries[end.file];
-		const boundary = boundaries_file[boundaries_file.length - 1];
-
-		boundary.end = end;
-		boundary.component = component;
-	}
-}
-
 /**
  * Sets up a validator that
  * - traverses the path of a prop to find out if it is allowed to be mutated

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

@@ -54,15 +54,14 @@ export function bind_not_bindable(key, component, name) {
 }
 
 /**
- * %parent% called `%method%` on an instance of %component%, which is no longer valid in Svelte 5
- * @param {string} parent
+ * Calling `%method%` on a component instance (of %component%) is no longer valid in Svelte 5
  * @param {string} method
  * @param {string} component
  * @returns {never}
  */
-export function component_api_changed(parent, method, component) {
+export function component_api_changed(method, component) {
 	if (DEV) {
-		const error = new Error(`component_api_changed\n${parent} called \`${method}\` on an instance of ${component}, which is no longer valid in Svelte 5\nhttps://svelte.dev/e/component_api_changed`);
+		const error = new Error(`component_api_changed\nCalling \`${method}\` on a component instance (of ${component}) is no longer valid in Svelte 5\nhttps://svelte.dev/e/component_api_changed`);
 
 		error.name = 'Svelte error';
 		throw error;

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

@@ -4,7 +4,7 @@ export { assign, assign_and, assign_or, assign_nullish } from './dev/assign.js';
 export { cleanup_styles } from './dev/css.js';
 export { add_locations } from './dev/elements.js';
 export { hmr } from './dev/hmr.js';
-export { mark_module_start, mark_module_end, create_ownership_validator } from './dev/ownership.js';
+export { create_ownership_validator } from './dev/ownership.js';
 export { check_target, legacy_api } from './dev/legacy.js';
 export { trace } from './dev/tracing.js';
 export { inspect } from './dev/inspect.js';