Merge branch '3.0-stable' into develop

Resolved conflicts:
	user_guide_src/source/changelog.rst
	user_guide_src/source/conf.py
	user_guide_src/source/installation/downloads.rst
	user_guide_src/source/installation/upgrading.rst

3 files changed, 91 insertions, 54 deletions

diff --git a/system/libraries/Form_validation.php b/system/libraries/Form_validation.php
index 9fb686892..e4a518957 100644
--- a/system/libraries/Form_validation.php
+++ b/system/libraries/Form_validation.php
@@ -486,7 +486,7 @@ class CI_Form_validation {
 		}
 
 		// Now we need to re-set the POST data with the new, processed data
-		$this->_reset_post_array();
+		empty($this->validation_data) && $this->_reset_post_array();
 
 		return ($total_errors === 0);
 	}
@@ -527,10 +527,7 @@ class CI_Form_validation {
 			{
 				if ($row['is_array'] === FALSE)
 				{
-					if (isset($_POST[$row['field']]))
-					{
-						$_POST[$row['field']] = $row['postdata'];
-					}
+					isset($_POST[$field]) && $_POST[$field] = $row['postdata'];
 				}
 				else
 				{
@@ -550,20 +547,7 @@ class CI_Form_validation {
 						}
 					}
 
-					if (is_array($row['postdata']))
-					{
-						$array = array();
-						foreach ($row['postdata'] as $k => $v)
-						{
-							$array[$k] = $v;
-						}
-
-						$post_ref = $array;
-					}
-					else
-					{
-						$post_ref = $row['postdata'];
-					}
+					$post_ref = $row['postdata'];
 				}
 			}
 		}
@@ -1515,10 +1499,11 @@ class CI_Form_validation {
 	 * This function allows HTML to be safely shown in a form.
 	 * Special characters are converted.
 	 *
-	 * @param	string
-	 * @return	string
+	 * @deprecated	3.0.6	Not used anywhere within the framework and pretty much useless
+	 * @param	mixed	$data	Input data
+	 * @return	mixed
 	 */
-	public function prep_for_form($data = '')
+	public function prep_for_form($data)
 	{
 		if ($this->_safe_form_data === FALSE OR empty($data))
 		{
diff --git a/system/libraries/Migration.php b/system/libraries/Migration.php
index 7aefb6c23..316c94ae3 100644
--- a/system/libraries/Migration.php
+++ b/system/libraries/Migration.php
@@ -96,9 +96,9 @@ class CI_Migration {
 	/**
 	 * Migration basename regex
 	 *
-	 * @var bool
+	 * @var string
 	 */
-	protected $_migration_regex = NULL;
+	protected $_migration_regex;
 
 	/**
 	 * Error message
@@ -217,31 +217,66 @@ class CI_Migration {
 
 		if ($target_version > $current_version)
 		{
-			// Moving Up
 			$method = 'up';
 		}
-		else
+		elseif ($target_version < $current_version)
 		{
-			// Moving Down, apply in reverse order
 			$method = 'down';
+			// We need this so that migrations are applied in reverse order
 			krsort($migrations);
 		}
-
-		if (empty($migrations))
+		else
 		{
+			// Well, there's nothing to migrate then ...
 			return TRUE;
 		}
 
-		$previous = FALSE;
-
-		// Validate all available migrations, and run the ones within our target range
+		// Validate all available migrations within our target range.
+		//
+		// Unfortunately, we'll have to use another loop to run them
+		// in order to avoid leaving the procedure in a broken state.
+		//
+		// See https://github.com/bcit-ci/CodeIgniter/issues/4539
+		$pending = array();
 		foreach ($migrations as $number => $file)
 		{
+			// Ignore versions out of our range.
+			//
+			// Because we've previously sorted the $migrations array depending on the direction,
+			// we can safely break the loop once we reach $target_version ...
+			if ($method === 'up')
+			{
+				if ($number <= $current_version)
+				{
+					continue;
+				}
+				elseif ($number > $target_version)
+				{
+					break;
+				}
+			}
+			else
+			{
+				if ($number > $current_version)
+				{
+					continue;
+				}
+				elseif ($number <= $target_version)
+				{
+					break;
+				}
+			}
+
 			// Check for sequence gaps
-			if ($this->_migration_type === 'sequential' && $previous !== FALSE && abs($number - $previous) > 1)
+			if ($this->_migration_type === 'sequential')
 			{
-				$this->_error_string = sprintf($this->lang->line('migration_sequence_gap'), $number);
-				return FALSE;
+				if (isset($previous) && abs($number - $previous) > 1)
+				{
+					$this->_error_string = sprintf($this->lang->line('migration_sequence_gap'), $number);
+					return FALSE;
+				}
+
+				$previous = $number;
 			}
 
 			include_once($file);
@@ -253,27 +288,27 @@ class CI_Migration {
 				$this->_error_string = sprintf($this->lang->line('migration_class_doesnt_exist'), $class);
 				return FALSE;
 			}
+			// method_exists() returns true for non-public methods,
+			// while is_callable() can't be used without instantiating.
+			// Only get_class_methods() satisfies both conditions.
+			elseif ( ! in_array($method, array_map('strtolower', get_class_methods($class))))
+			{
+				$this->_error_string = sprintf($this->lang->line('migration_missing_'.$method.'_method'), $class);
+				return FALSE;
+			}
 
-			$previous = $number;
+			$pending[$number] = array($class, $method);
+		}
 
-			// Run migrations that are inside the target range
-			if (
-				($method === 'up'   && $number > $current_version && $number <= $target_version) OR
-				($method === 'down' && $number <= $current_version && $number > $target_version)
-			)
-			{
-				$instance = new $class();
-				if ( ! is_callable(array($instance, $method)))
-				{
-					$this->_error_string = sprintf($this->lang->line('migration_missing_'.$method.'_method'), $class);
-					return FALSE;
-				}
+		// Now just run the necessary migrations
+		foreach ($pending as $number => $migration)
+		{
+			log_message('debug', 'Migrating '.$method.' from version '.$current_version.' to version '.$number);
 
-				log_message('debug', 'Migrating '.$method.' from version '.$current_version.' to version '.$number);
-				call_user_func(array($instance, $method));
-				$current_version = $number;
-				$this->_update_version($current_version);
-			}
+			$migration[0] = new $migration[0];
+			call_user_func($migration);
+			$current_version = $number;
+			$this->_update_version($current_version);
 		}
 
 		// This is necessary when moving down, since the the last migration applied
@@ -285,7 +320,6 @@ class CI_Migration {
 		}
 
 		log_message('debug', 'Finished migrating to '.$current_version);
-
 		return $current_version;
 	}
 
diff --git a/system/libraries/Session/Session.php b/system/libraries/Session/Session.php
index 77c56ae70..c9d2e8adc 100644
--- a/system/libraries/Session/Session.php
+++ b/system/libraries/Session/Session.php
@@ -584,6 +584,24 @@ class CI_Session {
 	// ------------------------------------------------------------------------
 
 	/**
+	 * __isset()
+	 *
+	 * @param	string	$key	'session_id' or a session data key
+	 * @return	bool
+	 */
+	public function __isset($key)
+	{
+		if ($key === 'session_id')
+		{
+			return (session_status() === PHP_SESSION_ACTIVE);
+		}
+
+		return isset($_SESSION[$key]);
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
 	 * __set()
 	 *
 	 * @param	string	$key	Session data key