fix: update warning codes for svelte5

.changeset/eleven-pears-compare.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/vite-plugin-svelte': patch
+---
+
+use correct warning code to hide unused css selector warning coming from vite-plugin-svelte injected code during development

packages/e2e-tests/import-queries/svelte.config.js

@@ -4,7 +4,7 @@ export default {
 	preprocess: [vitePreprocess()],
 	onwarn(warning, defaultHandler) {
 		// import query test generates one of these
-		if (warning.code === 'custom-element-no-tag') return;
+		if (warning.code === 'options_missing_custom_element') return;
 		defaultHandler(warning);
 	}
 };

packages/vite-plugin-svelte/src/utils/error.js

@@ -101,6 +101,16 @@ function formatFrameForVite(frame) {
 		.join('\n');
 }
 
+/**
+ *
+ * @param {string} code the svelte error code
+ * @see https://github.com/sveltejs/svelte/blob/main/packages/svelte/src/compiler/errors.js
+ * @returns {boolean}
+ */
+function couldBeFixedByCssPreprocessor(code) {
+	return code === 'expected_token' || code === 'unexpected_eof' || code.startsWith('css_');
+}
+
 /**
  * @param {import('svelte/compiler').Warning & Error} err a svelte compiler error, which is a mix of Warning and an error
  * @param {string} originalCode
@@ -113,7 +123,7 @@ export function enhanceCompileError(err, originalCode, preprocessors) {
 	const additionalMessages = [];
 
 	// Handle incorrect CSS preprocessor usage
-	if (err.code === 'css-syntax-error') {
+	if (couldBeFixedByCssPreprocessor(err.code)) {
 		// Reference from Svelte: https://github.com/sveltejs/svelte/blob/9926347ad9dbdd0f3324d5538e25dcb7f5e442f8/packages/svelte/src/compiler/preprocess/index.js#L257
 		const styleRe =
 			/<!--[^]*?-->|<style((?:\s+[^=>'"/]+=(?:"[^"]*"|'[^']*'|[^>\s]+)|\s+[^=>'"/]+)*\s*)(?:\/>|>([\S\s]*?)<\/style>)/g;

packages/vite-plugin-svelte/src/utils/log.js

@@ -182,7 +182,7 @@ export function logCompilerWarnings(svelteRequest, warnings, options) {
  */
 function ignoreCompilerWarning(warning, isBuild, emitCss) {
 	return (
-		(!emitCss && warning.code === 'css-unused-selector') || // same as rollup-plugin-svelte
+		(!emitCss && warning.code === 'css_unused_selector') || // same as rollup-plugin-svelte
 		(!isBuild && isNoScopableElementWarning(warning))
 	);
 }
@@ -194,7 +194,7 @@ function ignoreCompilerWarning(warning, isBuild, emitCss) {
  */
 function isNoScopableElementWarning(warning) {
 	// see https://github.com/sveltejs/vite-plugin-svelte/issues/153
-	return warning.code === 'css-unused-selector' && warning.message.includes('"*"');
+	return warning.code === 'css_unused_selector' && warning.message.includes('"*"');
 }
 
 /**