fix: parser error when using semicolon inside quotes in style

.changeset/seven-hornets-smile.md

@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+fix: correctly parse at-rules containing special characters in strings

packages/svelte/src/compiler/phases/1-parse/read/style.js

@@ -9,7 +9,6 @@ const REGEX_PERCENTAGE = /^\d+(\.\d+)?%/;
 const REGEX_NTH_OF =
 	/^(even|odd|\+?(\d+|\d*n(\s*[+-]\s*\d+)?)|-\d*n(\s*\+\s*\d+))((?=\s*[,)])|\s+of\s+)/;
 const REGEX_WHITESPACE_OR_COLON = /[\s:]/;
-const REGEX_BRACE_OR_SEMICOLON = /[{;]/;
 const REGEX_LEADING_HYPHEN_OR_DIGIT = /-?\d/;
 const REGEX_VALID_IDENTIFIER_CHAR = /[a-zA-Z0-9_-]/;
 const REGEX_COMMENT_CLOSE = /\*\//;
@@ -79,7 +78,7 @@ function read_at_rule(parser) {
 
 	const name = read_identifier(parser);
 
-	const prelude = parser.read_until(REGEX_BRACE_OR_SEMICOLON).trim();
+	const prelude = read_value(parser);
 
 	/** @type {import('#compiler').Css.Block | null} */
 	let block = null;
@@ -398,7 +397,7 @@ function read_declaration(parser) {
 	parser.eat(':');
 	parser.allow_whitespace();
 
-	const value = read_declaration_value(parser);
+	const value = read_value(parser);
 
 	const end = parser.index;
 
@@ -419,7 +418,7 @@ function read_declaration(parser) {
  * @param {import('../index.js').Parser} parser
  * @returns {string}
  */
-function read_declaration_value(parser) {
+function read_value(parser) {
 	let value = '';
 	let escaped = false;
 	let in_url = false;
@@ -443,7 +442,7 @@ function read_declaration_value(parser) {
 			quote_mark = char;
 		} else if (char === '(' && value.slice(-3) === 'url') {
 			in_url = true;
-		} else if ((char === ';' || char === '}') && !in_url && !quote_mark) {
+		} else if ((char === ';' || char === '{' || char === '}') && !in_url && !quote_mark) {
 			return value.trim();
 		}
 

packages/svelte/tests/parser-modern/samples/semicolon-inside-quotes/input.svelte

@@ -0,0 +1,10 @@
+<h1>
+	Semicolon inside quotes
+</h1>
+<style>
+	@import url("https://fonts.googleapis.com/css2?family=Poppins:wght@400;700&display=swap");
+	h1 {
+		font-weight: bold;
+		background: url("whatever");
+	}
+</style>

packages/svelte/tests/parser-modern/samples/semicolon-inside-quotes/output.json

@@ -0,0 +1,107 @@
+{
+	"css": {
+		"type": "Style",
+		"start": 36,
+		"end": 205,
+		"attributes": [],
+		"children": [
+			{
+				"type": "Atrule",
+				"start": 45,
+				"end": 135,
+				"name": "import",
+				"prelude": "url(\"https://fonts.googleapis.com/css2?family=Poppins:wght@400;700&display=swap\")",
+				"block": null
+			},
+			{
+				"type": "Rule",
+				"prelude": {
+					"type": "SelectorList",
+					"start": 137,
+					"end": 139,
+					"children": [
+						{
+							"type": "Selector",
+							"start": 137,
+							"end": 139,
+							"children": [
+								{
+									"type": "TypeSelector",
+									"name": "h1",
+									"start": 137,
+									"end": 139
+								}
+							]
+						}
+					]
+				},
+				"block": {
+					"type": "Block",
+					"start": 140,
+					"end": 196,
+					"children": [
+						{
+							"type": "Declaration",
+							"start": 144,
+							"end": 161,
+							"property": "font-weight",
+							"value": "bold"
+						},
+						{
+							"type": "Declaration",
+							"start": 165,
+							"end": 192,
+							"property": "background",
+							"value": "url(\"whatever\")"
+						}
+					]
+				},
+				"start": 137,
+				"end": 196
+			}
+		],
+		"content": {
+			"start": 43,
+			"end": 197,
+			"styles": "\n\t@import url(\"https://fonts.googleapis.com/css2?family=Poppins:wght@400;700&display=swap\");\n\th1 {\n\t\tfont-weight: bold;\n\t\tbackground: url(\"whatever\");\n\t}\n"
+		}
+	},
+	"js": [],
+	"start": 0,
+	"end": 35,
+	"type": "Root",
+	"fragment": {
+		"type": "Fragment",
+		"nodes": [
+			{
+				"type": "RegularElement",
+				"start": 0,
+				"end": 35,
+				"name": "h1",
+				"attributes": [],
+				"fragment": {
+					"type": "Fragment",
+					"nodes": [
+						{
+							"type": "Text",
+							"start": 4,
+							"end": 30,
+							"raw": "\n\tSemicolon inside quotes\n",
+							"data": "\n\tSemicolon inside quotes\n"
+						}
+					],
+					"transparent": true
+				}
+			},
+			{
+				"type": "Text",
+				"start": 35,
+				"end": 36,
+				"raw": "\n",
+				"data": "\n"
+			}
+		],
+		"transparent": false
+	},
+	"options": null
+}