From 2ecc354cb703ef4ce5c5bc2b9bfc15edd56f733c Mon Sep 17 00:00:00 2001
From: oleg <oleg.korobenko@gmail.com>
Date: Wed, 2 Mar 2016 19:37:36 +0300
Subject: [PATCH] catch cmd errors at spawn + detail error message

---
 lib/command/spawn.js   | 20 +++++++++++++++++++-
 test/commands/shell.js |  2 +-
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/lib/command/spawn.js b/lib/command/spawn.js
index 40f614e..e136498 100644
--- a/lib/command/spawn.js
+++ b/lib/command/spawn.js
@@ -23,6 +23,8 @@ Command.prototype.run = function(params, callback) {
 		stdout = self.collectOut ? '' : null,
 		stderr = self.attachStderr ? '' : null;
 
+	callback = _(callback).once();
+
 	if (!params.cmd) return callback(new Error('`cmd` is not set'));
 	if (!params.args) return callback(new Error('`args` is not set'));
 	params.options = params.options || {};
@@ -34,6 +36,16 @@ Command.prototype.run = function(params, callback) {
 		self.emit('stdin', params.cmd + ' ' + params.args.join(' ') + '\n');
 	}
 
+	var extendError = function (err) {
+		err.message = (
+			'Error while spawn "' +
+			[params.cmd].concat(params.args || []).join(' ') + '": ' +
+			err.message
+		);
+
+		return err;
+	};
+
 	cmd.stdout.on('data', function(data) {
 		if (self.emitOut) self.emit('stdout', data);
 		if (self.collectOut) stdout += data;
@@ -47,11 +59,17 @@ Command.prototype.run = function(params, callback) {
 	cmd.on('close', function(code) {
 		var err = null;
 		if (code !== 0) {
-			err = new Error('Spawned command exits with non-zero code: ' + code);
+			err = extendError(
+				new Error('Spawned command exits with non-zero code: ' + code)
+			);
 			err.stderr = stderr;
 		}
 		callback(err, stdout);
 	});
 
+	cmd.on('error', function(err) {
+		callback(extendError(err));
+	});
+
 	return cmd;
 };
diff --git a/test/commands/shell.js b/test/commands/shell.js
index 49ed5ce..610fbe7 100644
--- a/test/commands/shell.js
+++ b/test/commands/shell.js
@@ -44,7 +44,7 @@ describe('Shell command', function() {
 			// messages and codes are slightly different across the OSes
 			// e.g. at linux and macos
 			expect(err.message).match(
-				/^Spawned command exits with non-zero code: \d+/
+				/Spawned command exits with non-zero code: \d+/
 			);
 			expect(err.stderr).match(/echo1:.*not found/);
 			expect(std.err).equal('');