fix: handle closing tags inside attribute values (#9486)

Related to https://github.com/sveltejs/language-tools/issues/2204

.changeset/twelve-ears-act.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: handle closing tags inside attribute values

packages/svelte/src/compiler/preprocess/index.js

@@ -252,8 +252,10 @@ function stringify_tag_attributes(attributes) {
 	return value;
 }
 
-const regex_style_tags = /<!--[^]*?-->|<style(\s[^]*?)?(?:>([^]*?)<\/style>|\/>)/gi;
-const regex_script_tags = /<!--[^]*?-->|<script(\s[^]*?)?(?:>([^]*?)<\/script>|\/>)/gi;
+const regex_style_tags =
+	/<!--[^]*?-->|<style((?:\s+[^=>'"\/]+=(?:"[^"]*"|'[^']*'|[^>\s])|\s+[^=>'"\/]+)*\s*)(?:\/>|>([\S\s]*?)<\/style>)/g;
+const regex_script_tags =
+	/<!--[^]*?-->|<script((?:\s+[^=>'"\/]+=(?:"[^"]*"|'[^']*'|[^>\s])|\s+[^=>'"\/]+)*\s*)(?:\/>|>([\S\s]*?)<\/script>)/g;
 
 /**
  * Calculate the updates required to process all instances of the specified tag.

packages/svelte/test/preprocess/samples/attributes-with-closing-tag/_config.js

@@ -0,0 +1,6 @@
+export default {
+	preprocess: {
+		script: ({ attributes }) =>
+			attributes.generics && attributes.generics.includes('>') ? { code: '' } : null
+	}
+};

packages/svelte/test/preprocess/samples/attributes-with-closing-tag/input.svelte

@@ -0,0 +1,3 @@
+<script generics="T extends Record<string, string>">
+	foo {}
+</script>

packages/svelte/test/preprocess/samples/attributes-with-closing-tag/output.svelte

@@ -0,0 +1 @@
+<script generics="T extends Record<string, string>"></script>