fix(language-plugin-pug): ignore duplicate attribute error of class (#5100)

Author: KazariEX

packages/language-plugin-pug/index.ts

@@ -1,7 +1,9 @@
 import { SourceMap } from '@volar/source-map';
-import type { VueLanguagePlugin } from '@vue/language-core';
+import type { CompilerDOM, VueLanguagePlugin } from '@vue/language-core';
 import * as pug from 'volar-service-pug/lib/languageService';
 
+const classRegex = /^class\s*=/;
+
 const plugin: VueLanguagePlugin = ({ modules }) => {
 
 	return {
@@ -71,6 +73,13 @@ const plugin: VueLanguagePlugin = ({ modules }) => {
 							options?.onWarn?.(createProxyObject(warning));
 						},
 						onError(error) {
+							// #5099
+							if (
+								error.code === 2 satisfies CompilerDOM.ErrorCodes.DUPLICATE_ATTRIBUTE
+								&& classRegex.test(pugFile.htmlCode.slice(error.loc?.start.offset))
+							) {
+								return;
+							}
 							options?.onError?.(createProxyObject(error));
 						},
 					});

test-workspace/tsc/passedFixtures/pug/#5099.vue

@@ -0,0 +1,6 @@
+<template lang="pug">
+div(
+    class="foo"
+    class="bar"
+)
+</template>