fix: warn on undeclared shorthand event handlers on svelte:window/document/body (#18480)

Same as we already did on regular elements.
Fixes #18275

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>

.changeset/cool-spoons-tap.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: warn on undeclared shorthand event handlers on `<svelte:window>`, `<svelte:document>` and `<svelte:body>`

packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteBody.js

@@ -3,6 +3,7 @@
 import * as e from '../../../errors.js';
 import { is_event_attribute } from '../../../utils/ast.js';
 import { disallow_children } from './shared/special-element.js';
+import { check_global_event_reference } from './shared/utils.js';
 
 /**
  * @param {AST.SvelteBody} node
@@ -11,10 +12,9 @@ import { disallow_children } from './shared/special-element.js';
 export function SvelteBody(node, context) {
 	disallow_children(node);
 	for (const attribute of node.attributes) {
-		if (
-			attribute.type === 'SpreadAttribute' ||
-			(attribute.type === 'Attribute' && !is_event_attribute(attribute))
-		) {
+		if (attribute.type === 'Attribute' && is_event_attribute(attribute)) {
+			check_global_event_reference(attribute, context);
+		} else if (attribute.type === 'SpreadAttribute' || attribute.type === 'Attribute') {
 			e.svelte_body_illegal_attribute(attribute);
 		}
 	}

packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteDocument.js

@@ -3,6 +3,7 @@
 import { disallow_children } from './shared/special-element.js';
 import * as e from '../../../errors.js';
 import { is_event_attribute } from '../../../utils/ast.js';
+import { check_global_event_reference } from './shared/utils.js';
 
 /**
  * @param {AST.SvelteDocument} node
@@ -12,10 +13,9 @@ export function SvelteDocument(node, context) {
 	disallow_children(node);
 
 	for (const attribute of node.attributes) {
-		if (
-			attribute.type === 'SpreadAttribute' ||
-			(attribute.type === 'Attribute' && !is_event_attribute(attribute))
-		) {
+		if (attribute.type === 'Attribute' && is_event_attribute(attribute)) {
+			check_global_event_reference(attribute, context);
+		} else if (attribute.type === 'SpreadAttribute' || attribute.type === 'Attribute') {
 			e.illegal_element_attribute(attribute, 'svelte:document');
 		}
 	}

packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteWindow.js

@@ -3,6 +3,7 @@
 import { disallow_children } from './shared/special-element.js';
 import * as e from '../../../errors.js';
 import { is_event_attribute } from '../../../utils/ast.js';
+import { check_global_event_reference } from './shared/utils.js';
 
 /**
  * @param {AST.SvelteWindow} node
@@ -12,10 +13,9 @@ export function SvelteWindow(node, context) {
 	disallow_children(node);
 
 	for (const attribute of node.attributes) {
-		if (
-			attribute.type === 'SpreadAttribute' ||
-			(attribute.type === 'Attribute' && !is_event_attribute(attribute))
-		) {
+		if (attribute.type === 'Attribute' && is_event_attribute(attribute)) {
+			check_global_event_reference(attribute, context);
+		} else if (attribute.type === 'SpreadAttribute' || attribute.type === 'Attribute') {
 			e.illegal_element_attribute(attribute, 'svelte:window');
 		}
 	}

packages/svelte/src/compiler/phases/2-analyze/visitors/shared/element.js

@@ -9,6 +9,7 @@ import {
 	validate_attribute_name,
 	validate_slot_attribute
 } from './attribute.js';
+import { check_global_event_reference } from './utils.js';
 
 const EVENT_MODIFIERS = [
 	'preventDefault',
@@ -64,14 +65,7 @@ export function validate_element(node, context) {
 					e.attribute_invalid_event_handler(attribute);
 				}
 
-				const value = get_attribute_expression(attribute);
-				if (
-					value.type === 'Identifier' &&
-					value.name === attribute.name &&
-					!context.state.scope.get(value.name)
-				) {
-					w.attribute_global_event_reference(attribute, attribute.name);
-				}
+				check_global_event_reference(attribute, context);
 			}
 
 			if (attribute.name === 'slot') {

packages/svelte/src/compiler/phases/2-analyze/visitors/shared/utils.js

@@ -4,7 +4,11 @@
 /** @import { Scope } from '../../../scope' */
 /** @import { NodeLike } from '../../../../errors.js' */
 import * as e from '../../../../errors.js';
-import { extract_identifiers, get_parent } from '../../../../utils/ast.js';
+import {
+	extract_identifiers,
+	get_attribute_expression,
+	get_parent
+} from '../../../../utils/ast.js';
 import * as w from '../../../../warnings.js';
 import * as b from '#compiler/builders';
 import { get_rune } from '../../../scope.js';
@@ -298,3 +302,21 @@ export function validate_export(node, scope, name) {
 		e.state_invalid_export(node);
 	}
 }
+
+/**
+ * Warns when an event attribute uses the shorthand form (`{onclick}`) but the
+ * referenced name isn't declared, so it silently resolves to the global handler.
+ * @param {AST.Attribute & { value: [AST.ExpressionTag] | AST.ExpressionTag }} attribute
+ * @param {Context} context
+ */
+export function check_global_event_reference(attribute, context) {
+	const value = get_attribute_expression(attribute);
+
+	if (
+		value.type === 'Identifier' &&
+		value.name === attribute.name &&
+		!context.state.scope.get(value.name)
+	) {
+		w.attribute_global_event_reference(attribute, attribute.name);
+	}
+}

packages/svelte/tests/validator/samples/global-event-reference-special-elements/_config.js

@@ -0,0 +1,3 @@
+import { test } from '../../test';
+
+export default test({});

packages/svelte/tests/validator/samples/global-event-reference-special-elements/input.svelte

@@ -0,0 +1,7 @@
+<script>
+	let onkeydown;
+</script>
+
+<svelte:window {onkeydown} {onresize} />
+<svelte:document {onvisibilitychange} />
+<svelte:body {onfocus} />

packages/svelte/tests/validator/samples/global-event-reference-special-elements/warnings.json

@@ -0,0 +1,38 @@
+[
+	{
+		"code": "attribute_global_event_reference",
+		"message": "You are referencing `globalThis.onresize`. Did you forget to declare a variable with that name?",
+		"start": {
+			"column": 27,
+			"line": 5
+		},
+		"end": {
+			"column": 37,
+			"line": 5
+		}
+	},
+	{
+		"code": "attribute_global_event_reference",
+		"message": "You are referencing `globalThis.onvisibilitychange`. Did you forget to declare a variable with that name?",
+		"start": {
+			"column": 17,
+			"line": 6
+		},
+		"end": {
+			"column": 37,
+			"line": 6
+		}
+	},
+	{
+		"code": "attribute_global_event_reference",
+		"message": "You are referencing `globalThis.onfocus`. Did you forget to declare a variable with that name?",
+		"start": {
+			"column": 13,
+			"line": 7
+		},
+		"end": {
+			"column": 22,
+			"line": 7
+		}
+	}
+]