Improve error message when user passes a single array argument

Author: ehmicky

lib/command.js

@@ -11,7 +11,7 @@ const NO_ESCAPE_REGEXP = /^[\w.-]+$/;
 const DOUBLE_QUOTES_REGEXP = /"/g;
 
 const escapeArg = arg => {
-	if (NO_ESCAPE_REGEXP.test(arg)) {
+	if (typeof arg !== 'string' || NO_ESCAPE_REGEXP.test(arg)) {
 		return arg;
 	}
 

test/command.js

@@ -41,6 +41,10 @@ test(testEscapedCommand, '"foo bar"', ['foo bar']);
 test(testEscapedCommand, '"\\"foo\\""', ['"foo"']);
 test(testEscapedCommand, '"*"', ['*']);
 
+test('validate against passing a single array argument', async t => {
+	await t.throwsAsync(execa(['echo test']), /Received an instance of Array/);
+});
+
 test('allow commands with spaces and no array arguments', async t => {
 	const {stdout} = await execa('command with space');
 	t.is(stdout, '');