Check for --config file extensions after they fail to load, allowing custom loaders

lib/cli.js

@@ -250,8 +250,8 @@ export default async function loadCli() { // eslint-disable-line complexity
 	setChalk(chalkOptions);
 
 	if (confError) {
-		if (confError.parent) {
-			exit(`${confError.message}\n\n${chalk.gray((confError.parent && confError.parent.stack) || confError.parent)}`);
+		if (confError.cause) {
+			exit(`${confError.message}\n\n${chalk.gray(confError.cause?.stack ?? confError.cause)}`);
 		} else {
 			exit(confError.message);
 		}

lib/load-config.js

@@ -29,17 +29,13 @@ const loadConfigFile = async ({projectDir, configFile}) => {
 			return null;
 		}
 
-		throw Object.assign(new Error(`Error loading ${fileForErrorMessage}: ${error.message}`), {parent: error});
+		throw Object.assign(new Error(`Error loading ${fileForErrorMessage}: ${error.message}`), {cause: error});
 	}
 };
 
 function resolveConfigFile(configFile) {
 	if (configFile) {
 		configFile = path.resolve(configFile); // Relative to CWD
-
-		if (!configFile.endsWith('.js') && !configFile.endsWith('.cjs') && !configFile.endsWith('.mjs')) {
-			throw new Error('Config files must have .js, .cjs or .mjs extensions');
-		}
 	}
 
 	return configFile;
@@ -78,7 +74,7 @@ async function checkJsonFile(searchDir) {
 	}
 }
 
-export async function loadConfig({configFile, resolveFrom = process.cwd(), defaults = {}} = {}) {
+export async function loadConfig({configFile, resolveFrom = process.cwd(), defaults = {}} = {}) { // eslint-disable-line complexity
 	let packageConf = await packageConfig('ava', {cwd: resolveFrom});
 	const filepath = packageJsonPath(packageConf);
 	const projectDir = filepath === undefined ? resolveFrom : path.dirname(filepath);
@@ -94,7 +90,17 @@ export async function loadConfig({configFile, resolveFrom = process.cwd(), defau
 	let fileForErrorMessage;
 	let conflicting = [];
 	if (configFile) {
-		const loaded = await loadConfigFile({projectDir, configFile});
+		let loaded;
+		try {
+			loaded = await loadConfigFile({projectDir, configFile});
+		} catch (error) {
+			if (!configFile.endsWith('.js') && !configFile.endsWith('.cjs') && !configFile.endsWith('.mjs')) {
+				throw Object.assign(new Error('Could not load config file; it should have .js, .cjs or .mjs extension'), {cause: error});
+			}
+
+			throw error;
+		}
+
 		if (loaded !== null) {
 			({config: fileConf, fileForErrorMessage} = loaded);
 		}

test/config/loader.js

@@ -110,7 +110,7 @@ test.serial('receives a `projectDir` property', (...args) => ok('package-only')(
 });
 
 test.serial('rethrows wrapped module errors', notOk('throws'), (t, error) => {
-	t.is(error.parent.message, 'foo');
+	t.is(error.cause.message, 'foo');
 });
 
 test.serial('throws an error if a .js config file has no default export', notOk('no-default-export'));

test/config/snapshots/loader.js.md

@@ -14,7 +14,7 @@ Generated by [AVA](https://avajs.dev).
 
 > error message
 
-    'Config files must have .js, .cjs or .mjs extensions'
+    'Could not load config file; it should have .js, .cjs or .mjs extension'
 
 ## throws an error if a config factory does not return a plain object