Detached child process should not kill child - fixes #115 (#117)

fixtures/detach

@@ -0,0 +1,13 @@
+#!/usr/bin/env node
+const fs = require('fs');
+const execa = require('..');
+
+const fd = fs.openSync(process.argv[2], 'w');
+
+const cp = execa('noop', ['foo'], {
+	detached: true,
+	stdio: ['ignore', fd]
+});
+cp.unref();
+
+process.exit();

index.js

@@ -54,6 +54,11 @@ function handleArgs(cmd, args, opts) {
 		opts.env = npmRunPath.env(Object.assign({}, opts, {cwd: opts.localDir}));
 	}
 
+	if (opts.detached) {
+		// #115
+		opts.cleanup = false;
+	}
+
 	return {
 		cmd: parsed.command,
 		args: parsed.args,

test.js

@@ -489,3 +489,13 @@ test('do not buffer when streaming', async t => {
 
 	t.is(result, '....................\n');
 });
+
+test('detach child process', async t => {
+	const file = tempfile('.txt');
+
+	await m('detach', [file]);
+
+	await delay(2000);
+
+	t.is(fs.readFileSync(file, 'utf8'), 'foo\n');
+});