Allow to fail a task with a message via Mage_Task_ErrorWithMessageException

Mage/Command/BuiltIn/Deploy.php

@@ -305,6 +305,10 @@ class Mage_Command_BuiltIn_Deploy
                     Mage_Console::output('<red>FAIL</red>', 0);
                     $result = false;
                 }
+            } catch (Mage_Task_ErrorWithMessageException $e) {
+            	Mage_Console::output('<red>FAIL</red> [Message: ' . $e->getMessage() . ']', 0);
+            	$result = false;
+
             } catch (Mage_Task_SkipException $e) {
                 Mage_Console::output('<yellow>SKIPPED</yellow>', 0);
                 $result = true;

Mage/Task/BuiltIn/Scm/ChangeBranch.php

@@ -2,7 +2,7 @@
 class Mage_Task_BuiltIn_Scm_ChangeBranch
     extends Mage_Task_TaskAbstract
 {
-	protected static $_startingBranch = 'master';
+	protected static $startingBranch = 'master';
     private $_name = 'SCM Changing branch [built-in]';
 
     public function getName()
@@ -25,10 +25,11 @@ class Mage_Task_BuiltIn_Scm_ChangeBranch
 
     public function run()
     {
-        switch ($this->getConfig()->general('scm')) {
+    	$scmConfig = $this->getConfig()->general('scm', array());
+        switch ((isset($scmConfig['type']) ? $scmConfig['type'] : false)) {
             case 'git':
             	if ($this->getParameter('_changeBranchRevert', false)) {
-            		$command = 'git checkout ' . self::$_startingBranch;
+            		$command = 'git checkout ' . self::$startingBranch;
             		$result = $this->_runLocalCommand($command);
 
             	} else {
@@ -37,19 +38,25 @@ class Mage_Task_BuiltIn_Scm_ChangeBranch
             		$result = $this->_runLocalCommand($command, $currentBranch);
 
             		$scmData = $this->getConfig()->deployment('scm', false);
-            		if ($result && is_array($scmData) && isset($scmData['branch'])) {
-            			$branch = $this->getParameter('branch', $scmData['branch']);
-            			$command = 'git checkout ' . $branch;
-            			$result = $this->_runLocalCommand($command);
 
-            			self::$_startingBranch = $currentBranch;
+            		if ($result && is_array($scmData) && isset($scmData['branch']) && $scmData['branch'] != $currentBranch) {
+        				$command = 'git branch | grep \'' . $scmData['branch'] . '\' | tr -s \' \' | sed \'s/^[ ]//g\'';
+        				$isBranchTracked = '';
+        				$result = $this->_runLocalCommand($command, $isBranchTracked);
+
+        				if ($isBranchTracked == '') {
+        					throw new Mage_Task_ErrorWithMessageException('The branch <purple>' . $scmData['branch'] . '</purple> must be tracked.');
+        				}
+
+        				$branch = $this->getParameter('branch', $scmData['branch']);
+        				$command = 'git checkout ' . $branch;
+        				$result = $this->_runLocalCommand($command);
 
+        				self::$startingBranch = $currentBranch;
             		} else {
             			throw new Mage_Task_SkipException;
             		}
             	}
-
-
                 break;
 
             default:

Mage/Task/ErrorWithMessageException.php

@@ -0,0 +1,6 @@
+<?php
+class Mage_Task_ErrorWithMessageException
+extends Exception
+{
+
+}

docs/example-config/.mage/config/environment/staging.yml

@@ -4,7 +4,7 @@ deployment:
   from: ./
   to: /var/www/
   scm:
-    branch: master
+    branch: master2
 releases:
   enabled: true
   max: 5