Change Branch on pre-deployment.

Mage/Command/BuiltIn/Deploy.php

@@ -49,7 +49,7 @@ class Mage_Command_BuiltIn_Deploy
 
                 if (count($tasksToRun) == 0) {
                     Mage_Console::output('<light_purple>Warning!</light_purple> <dark_gray>No </dark_gray><light_cyan>Deployment</light_cyan> <dark_gray>tasks defined.</dark_gray>', 2);
-                    Mage_Console::output('Deployment to <dark_gray>' . $config->getHost() . '</dark_gray> skipped!', 1, 3);
+                    Mage_Console::output('Deployment to <dark_gray>' . $host . '</dark_gray> skipped!', 1, 3);
 
                 } else {
                     foreach ($tasksToRun as $taskData) {
@@ -150,12 +150,29 @@ class Mage_Command_BuiltIn_Deploy
     {
         $tasksToRun = $config->getTasks($stage);
 
-        // Look for Remote Source
-        if (is_array($this->_config->deployment('source', null))) {
-            if ($stage == 'pre-deploy') {
-                array_unshift($tasksToRun, 'scm/clone');
-            } elseif ($stage == 'post-deploy') {
-                array_unshift($tasksToRun, 'scm/remove-clone');
+        // PreDeployment Hook
+        if ($stage == 'pre-deploy') {
+        	// Look for Remote Source
+        	if (is_array($this->_config->deployment('source', null))) {
+        		array_unshift($tasksToRun, 'scm/clone');
+        	}
+
+        	// Change Branch
+        	if ($this->getConfig()->deployment('scm', false)) {
+        		array_unshift($tasksToRun, 'scm/change-branch');
+        	}
+        }
+
+        // PostDeployment Hook
+        if ($stage == 'post-deploy') {
+        	// Change Branch Back
+        	if ($this->getConfig()->deployment('scm', false)) {
+        		array_unshift($tasksToRun, 'scm/change-branch-back');
+        	}
+
+        	// Remove Remote Source
+        	if (is_array($this->_config->deployment('source', null))) {
+        		 array_push($tasksToRun, 'scm/remove-clone');
             }
         }
 

Mage/Task/BuiltIn/Scm/ChangeBranch.php

@@ -0,0 +1,58 @@
+<?php
+class Mage_Task_BuiltIn_Scm_ChangeBranch
+    extends Mage_Task_TaskAbstract
+{
+    private $_name = 'SCM Changing branch [built-in]';
+
+    public function getName()
+    {
+        return $this->_name;
+    }
+
+    public function init()
+    {
+        switch ($this->getConfig()->scm('type')) {
+            case 'git':
+                $this->_name = 'SCM Changing branch (GIT) [built-in]';
+                break;
+
+            case 'svn':
+                $this->_name = 'SCM Changing branch (Subversion) [built-in]';
+                break;
+        }
+    }
+
+    public function run()
+    {
+        switch ($this->getConfig()->scm('type')) {
+            case 'git':
+            	$command = 'git branch | grep \'*\' | cut -d\' \' -f 2';
+            	$currentBranch = 'master';
+            	$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);
+
+                	$oldBranchFile = '.mage/' . $this->getConfig()->getEnvironment() . '.oldBranch';
+                	file_put_contents($oldBranchFile, $currentBranch);
+
+                } else {
+                    throw new Mage_Task_SkipException;
+                }
+
+                break;
+
+            default:
+                return false;
+                break;
+        }
+
+
+        $this->getConfig()->reload();
+
+        return $result;
+    }
+}

Mage/Task/BuiltIn/Scm/ChangeBranchBack.php

@@ -0,0 +1,47 @@
+<?php
+class Mage_Task_BuiltIn_Scm_ChangeBranchBack
+    extends Mage_Task_TaskAbstract
+{
+    private $_name = 'SCM Changing branch Back [built-in]';
+
+    public function getName()
+    {
+        return $this->_name;
+    }
+
+    public function init()
+    {
+        switch ($this->getConfig()->scm('type')) {
+            case 'git':
+                $this->_name = 'SCM Changing branch Back (GIT) [built-in]';
+                break;
+
+            case 'svn':
+                $this->_name = 'SCM Changing branch Back (Subversion) [built-in]';
+                break;
+        }
+    }
+
+    public function run()
+    {
+        switch ($this->getConfig()->scm('type')) {
+            case 'git':
+            	$oldBranchFile = '.mage/' . $this->getConfig()->getEnvironment() . '.oldBranch';
+            	$currentBranch = trim(file_get_contents($oldBranchFile));
+
+            	$command = 'git checkout ' . $currentBranch;
+            	$result = $this->_runLocalCommand($command);
+            	@unlink($oldBranchFile);
+                break;
+
+            default:
+                return false;
+                break;
+        }
+
+
+        $this->getConfig()->reload();
+
+        return $result;
+    }
+}

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

@@ -3,18 +3,20 @@ deployment:
   user: root
   from: ./
   to: /var/www/
+  scm:
+    branch: master
 releases:
   enabled: true
   max: 5
   symlink: current
   directory: releases
 hosts:
-  - localhost
-  - dbserver
+#  - localhost
+#  - dbserver
 tasks:
   pre-deploy:
     - sampleTask
-#    - scm/update
+    - scm/update
   on-deploy:
     - privileges
     - sampleTask