fix: highlight line with error in the error overlay

.changeset/old-bats-travel.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes line with the error not being properly highlighted in the error overlay

packages/astro/e2e/errors.test.js

@@ -131,4 +131,12 @@ test.describe('Error display', () => {
 		const message = (await getErrorOverlayContent(page)).message;
 		expect(message).toMatch('The operation was aborted due to timeout');
 	});
+
+	test('properly highlight the line with the error', async ({ page, astro }) => {
+		await page.goto(astro.resolveUrl('/import-not-found'), { waitUntil: 'networkidle' });
+
+		const { codeFrame } = await getErrorOverlayContent(page);
+		const codeFrameContent = await codeFrame.innerHTML();
+		expect(codeFrameContent).toContain('error-line');
+	});
 });

packages/astro/e2e/test-utils.js

@@ -51,8 +51,8 @@ export function testFactory(inlineConfig) {
 
 /**
  *
- * @param {string} page
- * @returns {Promise<{message: string, hint: string, absoluteFileLocation: string, fileLocation: string}>}
+ * @param {import('@playwright/test').Page} page
+ * @returns {Promise<{message: string, hint: string, absoluteFileLocation: string, fileLocation: string, codeFrame: import('@playwright/test').ElementHandle}>}
  */
 export async function getErrorOverlayContent(page) {
 	const overlay = await page.waitForSelector('vite-error-overlay', {
@@ -68,7 +68,10 @@ export async function getErrorOverlayContent(page) {
 		m[0].title,
 		m[0].textContent,
 	]);
-	return { message, hint, absoluteFileLocation, fileLocation };
+
+	const codeFrame = await overlay.$('#code pre code');
+
+	return { message, hint, absoluteFileLocation, fileLocation, codeFrame };
 }
 
 /**

packages/astro/src/core/errors/dev/vite.ts

@@ -1,6 +1,7 @@
 import * as fs from 'node:fs';
 import { fileURLToPath } from 'node:url';
 import { codeToHtml, createCssVariablesTheme } from 'shiki';
+import type { ShikiTransformer } from 'shiki';
 import type { ErrorPayload } from 'vite';
 import type { ModuleLoader } from '../../module-loader/index.js';
 import { FailedToLoadModuleSSR, InvalidGlob, MdxIntegrationMissingError } from '../errors-data.js';
@@ -151,10 +152,13 @@ export async function getViteErrorPayload(err: ErrorWithMetadata): Promise<Astro
 	}
 	const highlightedCode = err.fullCode
 		? await codeToHtml(err.fullCode, {
-				// @ts-expect-error always assume that shiki can accept the lang string
-				lang: highlighterLang,
+				lang: highlighterLang ?? 'text',
 				theme: cssVariablesTheme(),
-				lineOptions: err.loc?.line ? [{ line: err.loc.line, classes: ['error-line'] }] : undefined,
+				transformers: [
+					transformerCompactLineOptions(
+						err.loc?.line ? [{ line: err.loc.line, classes: ['error-line'] }] : undefined
+					),
+				],
 			})
 		: undefined;
 
@@ -180,3 +184,27 @@ export async function getViteErrorPayload(err: ErrorWithMetadata): Promise<Astro
 		},
 	};
 }
+
+/**
+ * Transformer for `shiki`'s legacy `lineOptions`, allows to add classes to specific lines
+ * FROM: https://github.com/shikijs/shiki/blob/4a58472070a9a359a4deafec23bb576a73e24c6a/packages/transformers/src/transformers/compact-line-options.ts
+ * LICENSE: https://github.com/shikijs/shiki/blob/4a58472070a9a359a4deafec23bb576a73e24c6a/LICENSE
+ */
+export function transformerCompactLineOptions(
+	lineOptions: {
+		/**
+		 * 1-based line number.
+		 */
+		line: number;
+		classes?: string[];
+	}[] = []
+): ShikiTransformer {
+	return {
+		name: '@shikijs/transformers:compact-line-options',
+		line(node, line) {
+			const lineOption = lineOptions.find((o) => o.line === line);
+			if (lineOption?.classes) this.addClassToHast(node, lineOption.classes);
+			return node;
+		},
+	};
+}