fix: remove buggy `validate_dynamic_component` check (#12960)

closes #12857

.changeset/young-peaches-agree.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: remove buggy `validate_dynamic_component` check

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

@@ -348,14 +348,7 @@ export function build_component(node, component_name, context, anchor = context.
 				b.thunk(/** @type {Expression} */ (context.visit(node.expression))),
 				b.arrow(
 					[b.id('$$anchor'), b.id(component_name)],
-					b.block([
-						...binding_initializers,
-						b.stmt(
-							dev
-								? b.call('$.validate_dynamic_component', b.thunk(prev(b.id('$$anchor'))))
-								: prev(b.id('$$anchor'))
-						)
-					])
+					b.block([...binding_initializers, b.stmt(prev(b.id('$$anchor')))])
 				)
 			);
 		};

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

@@ -144,12 +144,7 @@ export {
 	setContext,
 	hasContext
 } from './runtime.js';
-export {
-	validate_binding,
-	validate_dynamic_component,
-	validate_each_keys,
-	validate_prop_bindings
-} from './validate.js';
+export { validate_binding, validate_each_keys, validate_prop_bindings } from './validate.js';
 export { raf } from './timing.js';
 export { proxy } from './proxy.js';
 export { create_custom_element } from './dom/elements/custom-element.js';

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

@@ -14,31 +14,6 @@ function is_void(tag) {
 	return void_element_names.test(tag) || tag.toLowerCase() === '!doctype';
 }
 
-/**
- * @template Component
- * @param {() => Component} component_fn
- * @returns {Component}
- */
-export function validate_dynamic_component(component_fn) {
-	try {
-		const instance = component_fn();
-
-		if (instance !== undefined && typeof instance !== 'object') {
-			e.svelte_component_invalid_this_value();
-		}
-
-		return instance;
-	} catch (err) {
-		const { message } = /** @type {Error} */ (err);
-
-		if (typeof message === 'string' && message.indexOf('is not a function') !== -1) {
-			e.svelte_component_invalid_this_value();
-		}
-
-		throw err;
-	}
-}
-
 /**
  * @param {() => any} collection
  * @param {(item: any, index: number) => string} key_fn

packages/svelte/tests/runtime-legacy/samples/component-not-constructor-dev/_config.js

@@ -1,12 +0,0 @@
-import { test } from '../../test';
-
-export default test({
-	mode: ['client'],
-
-	compileOptions: {
-		dev: true
-	},
-
-	error:
-		'svelte_component_invalid_this_value\nThe `this={...}` property of a `<svelte:component>` must be a Svelte component, if defined'
-});

packages/svelte/tests/runtime-legacy/samples/component-not-constructor-dev/main.svelte

@@ -1,5 +0,0 @@
-<script>
-	let banana = {};
-</script>
-
-<svelte:component this={banana} />

packages/svelte/tests/runtime-legacy/samples/component-not-constructor2-dev/Sub.svelte

@@ -1 +0,0 @@
-<div>Sub</div>

packages/svelte/tests/runtime-legacy/samples/component-not-constructor2-dev/_config.js

@@ -1,24 +0,0 @@
-import { test } from '../../test';
-
-export default test({
-	compileOptions: {
-		dev: true
-	},
-	get props() {
-		return { componentName: 'Sub' };
-	},
-	html: '<div>Sub</div>',
-	test({ assert, component, target }) {
-		component.componentName = 'Proxy';
-		assert.htmlEqual(target.innerHTML, '<div>Sub</div>');
-		try {
-			component.componentName = 'banana';
-			throw new Error('Expected an error');
-		} catch (err) {
-			assert.include(
-				/** @type {Error} */ (err).message,
-				'svelte_component_invalid_this_value\nThe `this={...}` property of a `<svelte:component>` must be a Svelte component, if defined'
-			);
-		}
-	}
-});

packages/svelte/tests/runtime-legacy/samples/component-not-constructor2-dev/main.svelte

@@ -1,14 +0,0 @@
-<script>
-	import Sub from './Sub.svelte';
-	export let componentName = 'Sub';
-	let proxy = new Proxy(Sub, {});
-	let banana = {};
-	let component;
-	$: {
-		if (componentName === 'Sub') component = Sub;
-		else if (componentName === 'Proxy') component = proxy;
-		else component = banana;
-	};
-</script>
-
-<svelte:component this={component} />