feat: bubble up ESLint config errors

Author: spence-s

lib/handle-ts-files.ts

@@ -68,11 +68,13 @@ export async function handleTsconfig({cwd, files}: {cwd: string; files: string[]
 
 	tsConfig.files = unincludedFiles;
 
-	try {
-		await fs.mkdir(path.dirname(fallbackTsConfigPath), {recursive: true});
-		await fs.writeFile(fallbackTsConfigPath, JSON.stringify(tsConfig, null, 2));
-	} catch (error) {
-		console.error(error);
+	if (unincludedFiles.length > 0) {
+		try {
+			await fs.mkdir(path.dirname(fallbackTsConfigPath), {recursive: true});
+			await fs.writeFile(fallbackTsConfigPath, JSON.stringify(tsConfig, null, 2));
+		} catch (error) {
+			console.error(error);
+		}
 	}
 
 	return {unincludedFiles, fallbackTsConfigPath};

lib/resolve-config.ts

@@ -1,7 +1,6 @@
 import path from 'node:path';
 import process from 'node:process';
 import {cosmiconfig, defaultLoaders} from 'cosmiconfig';
-import pick from 'lodash.pick';
 import arrify from 'arrify';
 import {type FlatXoConfig, type LinterOptions, type XoConfigItem} from './types.js';
 import {moduleName} from './constants.js';
@@ -49,22 +48,7 @@ export async function resolveXoConfig(options: LinterOptions): Promise<{
 			filepath: flatConfigPath = '',
 		} = await (flatConfigExplorer.search(searchPath) as Promise<{config: FlatXoConfig | undefined; filepath: string}>) ?? {};
 
-		const globalKeys = [
-			'ignores',
-			'settings',
-			'parserOptions',
-			'prettier',
-			'semicolon',
-			'space',
-			'rules',
-			'env',
-			'extension',
-			'files',
-			'plugins',
-			'react',
-		];
-
-		flatOptions = arrify(flatOptions).map(config => pick(config, globalKeys));
+		flatOptions = arrify(flatOptions);
 
 		return {
 			flatOptions,

package.json

@@ -89,7 +89,6 @@
 		"get-tsconfig": "^4.10.0",
 		"globals": "^16.0.0",
 		"globby": "^14.1.0",
-		"lodash.pick": "^4.4.0",
 		"meow": "^13.2.0",
 		"micromatch": "^4.0.8",
 		"open-editor": "^5.1.0",
@@ -102,7 +101,6 @@
 		"@commitlint/cli": "^19.8.0",
 		"@commitlint/config-conventional": "^19.8.0",
 		"@types/eslint": "9.6.1",
-		"@types/lodash.pick": "^4.4.9",
 		"@types/micromatch": "^4.0.9",
 		"@types/prettier": "^3.0.0",
 		"ava": "^6.2.0",

test/cli.test.ts

@@ -335,3 +335,20 @@ test('gives helpful error message when config creates a circular dependency', as
 	const error = await t.throwsAsync<ExecaError>($`node ./dist/cli --cwd ${t.context.cwd}`);
 	t.true((error.stderr as string)?.includes('Error resolving XO config'));
 });
+
+test('Config errors bubble up from ESLint when incorrect config options are set', async t => {
+	const filePath = path.join(t.context.cwd, 'test.js');
+	await fs.writeFile(filePath, dedent`console.log('hello');\n`, 'utf8');
+	const xoConfigPath = path.join(t.context.cwd, 'xo.config.js');
+	const xoConfig = dedent`
+		export default [
+			{
+				invalidOption: 'some invalid value',
+				space: true
+			}
+		]
+	`;
+	await fs.writeFile(xoConfigPath, xoConfig, 'utf8');
+	const error = await t.throwsAsync<ExecaError>($`node ./dist/cli --cwd ${t.context.cwd}`);
+	t.true((error.stderr as string)?.includes('ConfigError:') && (error.stderr as string)?.includes('Unexpected key "invalidOption" found'));
+});