diff --git a/build/build.xml b/build/build.xml
index f29be5326d..31782e6821 100644
--- a/build/build.xml
+++ b/build/build.xml
@@ -3,7 +3,7 @@
 <project name="phpBB" description="The phpBB forum software" default="all" basedir="../">
 	<!-- a few settings for the build -->
 	<property name="newversion" value="3.1.0-dev" />
-	<property name="prevversion" value="3.0.12-RC3" />
+	<property name="prevversion" value="3.0.12" />
 	<property name="olderversions" value="3.0.2, 3.0.3, 3.0.4, 3.0.5, 3.0.6, 3.0.7, 3.0.7-PL1, 3.0.8, 3.0.9, 3.0.10, 3.0.11" />
 	<!-- no configuration should be needed beyond this point -->
 
@@ -149,6 +149,24 @@
 		<exec dir="build" escape="false"
 			command="git diff --stat release-${prevversion}...HEAD >
 				save/save_${prevversion}_to_${newversion}/phpbb-${prevversion}_to_${newversion}_git_diffstat.txt" />
+
+		<phingcall target="checksum-dir">
+			<property name="dir" value="build/new_version/release_files" />
+		</phingcall>
+	</target>
+
+	<target name="checksum-dir">
+		<foreach param="filename" absparam="absfilename" target="checksum-file">
+			<fileset dir="${dir}">
+				<type type="file" />
+			</fileset>
+		</foreach>
+	</target>
+
+	<target name="checksum-file">
+		<echo msg="Creating checksum file for ${absfilename}" />
+		<php function="dirname" returnProperty="dir"><param value="${absfilename}"/></php>
+		<exec dir="${dir}" command="sha256sum ${filename} > ${filename}.sha256" />
 	</target>
 
 	<target name="changelog" depends="prepare">
diff --git a/build/build_diff.php b/build/build_diff.php
index 74630232b3..68bac65a66 100755
--- a/build/build_diff.php
+++ b/build/build_diff.php
@@ -83,9 +83,6 @@ if (!$echo_changes)
 
 		// Build Package
 		run_command("$compress_command ./../../new_version/release_files/{$code_changes_filename}.{$extension} *");
-
-		// Build MD5 Sum
-		run_command("md5sum ./../../new_version/release_files/{$code_changes_filename}.{$extension} > ./../../new_version/release_files/{$code_changes_filename}.{$extension}.md5");
 		flush();
 	}
 }
diff --git a/build/package.php b/build/package.php
index eef6765af6..d05448dfb4 100755
--- a/build/package.php
+++ b/build/package.php
@@ -287,9 +287,6 @@ if (sizeof($package->old_packages))
 
 		// Build Package
 		$package->run_command($compress_command . ' ../release_files/' . $package->get('release_filename') . '-patch.' . $extension . ' *');
-
-		// Build MD5 Sum
-		$package->run_command('md5sum ../release_files/' . $package->get('release_filename') . '-patch.' . $extension . ' > ../release_files/' . $package->get('release_filename') . '-patch.' . $extension . '.md5');
 	}
 
 	// Build Files Package
@@ -321,8 +318,6 @@ if (sizeof($package->old_packages))
 
 		chdir('./release');
 		$package->run_command("$compress_command ../../release_files/" . $package->get('release_filename') . '-files.' . $extension . ' *');
-		// Build MD5 Sum
-		$package->run_command('md5sum ../../release_files/' . $package->get('release_filename') . '-files.' . $extension . ' > ../../release_files/' . $package->get('release_filename') . '-files.' . $extension . '.md5');
 		chdir('..');
 
 		$package->run_command('rm -Rv ' . $package->get('files_directory') . '/release');
@@ -365,9 +360,6 @@ if (sizeof($package->old_packages))
 			// Copy last package over...
 			$package->run_command('rm -v ../release_files/phpBB-' . $last_version . ".$extension");
 			$package->run_command("$compress_command ../../release_files/phpBB-$last_version.$extension *");
-
-			// Build MD5 Sum
-			$package->run_command("md5sum ../../release_files/phpBB-$last_version.$extension > ../../release_files/phpBB-$last_version.$extension.md5");
 			chdir('..');
 		}
 
@@ -390,9 +382,6 @@ foreach ($compress_programs as $extension => $compress_command)
 
 	// Build Package
 	$package->run_command("$compress_command ./release_files/" . $package->get('release_filename') . '.' . $extension . ' ' . $package->get('package_name'));
-
-	// Build MD5 Sum
-	$package->run_command('md5sum ./release_files/' . $package->get('release_filename') . '.' . $extension . ' > ./release_files/' . $package->get('release_filename') . '.' . $extension . '.md5');
 }
 
 // Microsoft Web PI packaging
@@ -400,7 +389,6 @@ $package->begin_status('Packaging phpBB for Microsoft WebPI');
 $file = './release_files/' . $package->get('release_filename') . '.webpi.zip';
 $package->run_command('cp -p ./release_files/' . $package->get('release_filename') . ".zip $file");
 $package->run_command('cd ./../webpi && ' . $compress_programs['zip'] . " ./../new_version/$file *");
-$package->run_command("md5sum $file  > $file.md5");
 
 // verify results
 chdir($package->locations['root']);
diff --git a/phpBB/app.php b/phpBB/app.php
index f1023ff1b5..7dc778e3a8 100644
--- a/phpBB/app.php
+++ b/phpBB/app.php
@@ -25,6 +25,7 @@ $auth->acl($user->data);
 $user->setup('app');
 
 $http_kernel = $phpbb_container->get('http_kernel');
+$symfony_request = $phpbb_container->get('symfony_request');
 $response = $http_kernel->handle($symfony_request);
 $response->send();
 $http_kernel->terminate($symfony_request, $response);
diff --git a/phpBB/common.php b/phpBB/common.php
index 80375f7a9c..6bb3509ea1 100644
--- a/phpBB/common.php
+++ b/phpBB/common.php
@@ -47,19 +47,7 @@ if (!defined('PHPBB_INSTALLED'))
 
 	// Eliminate . and .. from the path
 	require($phpbb_root_path . 'phpbb/filesystem.' . $phpEx);
-	require($phpbb_root_path . 'phpbb/symfony_request.' . $phpEx);
-	require($phpbb_root_path . 'phpbb/request/deactivated_super_global.' . $phpEx);
-	require($phpbb_root_path . 'phpbb/request/type_cast_helper_interface.' . $phpEx);
-	require($phpbb_root_path . 'phpbb/request/type_cast_helper.' . $phpEx);
-	require($phpbb_root_path . 'phpbb/request/request_interface.' . $phpEx);
-	require($phpbb_root_path . 'phpbb/request/request.' . $phpEx);
-	$phpbb_filesystem = new phpbb\filesystem(
-		new phpbb\symfony_request(
-			new phpbb\request\request()
-		),
-		$phpbb_root_path,
-		$phpEx
-	);
+	$phpbb_filesystem = new phpbb\filesystem();
 	$script_path = $phpbb_filesystem->clean_path($script_path);
 
 	$url = (($secure) ? 'https://' : 'http://') . $server_name;
@@ -121,16 +109,13 @@ $db			= $phpbb_container->get('dbal.conn');
 // make sure request_var uses this request instance
 request_var('', 0, false, false, $request); // "dependency injection" for a function
 
-// Create a Symfony Request object from our phpbb_request object
-$symfony_request = $phpbb_container->get('symfony_request');
-$phpbb_filesystem = $phpbb_container->get('filesystem');
-
 // Grab global variables, re-cache if necessary
 $config = $phpbb_container->get('config');
 set_config(null, null, null, $config);
 set_config_count(null, null, null, $config);
 
 $phpbb_log = $phpbb_container->get('log');
+$phpbb_path_helper = $phpbb_container->get('path_helper');
 
 // load extensions
 $phpbb_extension_manager = $phpbb_container->get('ext.manager');
diff --git a/phpBB/config/services.yml b/phpBB/config/services.yml
index 7a0a215262..1af0457331 100644
--- a/phpBB/config/services.yml
+++ b/phpBB/config/services.yml
@@ -170,11 +170,6 @@ services:
 
     filesystem:
         class: phpbb\filesystem
-        arguments:
-            - @symfony_request
-            - %core.root_path%
-            - %core.php_ext%
-            - %core.adm_relative_path%
 
     groupposition.legend:
         class: phpbb\groupposition\legend
@@ -252,6 +247,15 @@ services:
             - %tables.notifications%
             - %tables.user_notifications%
 
+    path_helper:
+        class: phpbb\path_helper
+        arguments:
+            - @symfony_request
+            - @filesystem
+            - %core.root_path%
+            - %core.php_ext%
+            - %core.adm_relative_path%
+
     php_ini:
         class: phpbb\php\ini
 
@@ -266,7 +270,7 @@ services:
     template:
         class: phpbb\template\twig\twig
         arguments:
-            - @filesystem
+            - @path_helper
             - @config
             - @user
             - @template_context
diff --git a/phpBB/docs/CHANGELOG.html b/phpBB/docs/CHANGELOG.html
index c2eb48137a..2be63eb866 100644
--- a/phpBB/docs/CHANGELOG.html
+++ b/phpBB/docs/CHANGELOG.html
@@ -211,6 +211,7 @@
 <li>[<a href="http://tracker.phpbb.com/browse/PHPBB3-11368">PHPBB3-11368</a>] - Latest pm reports row count</li>
 <li>[<a href="http://tracker.phpbb.com/browse/PHPBB3-11583">PHPBB3-11583</a>] - InnoDB supports FULLTEXT index since MySQL 5.6.4.</li>
 <li>[<a href="http://tracker.phpbb.com/browse/PHPBB3-11740">PHPBB3-11740</a>] - Update link in FAQ to Ideas Centre</li>
+<li>[<a href="http://tracker.phpbb.com/browse/PHPBB3-11873">PHPBB3-11873</a>] - Prevent expensive hash computation in phpbb_check_hash() by rejecting very long passwords</li>
 </ul>
 <h4>Sub-task</h4>
 <ul>
diff --git a/phpBB/includes/bbcode.php b/phpBB/includes/bbcode.php
index cd2ca7ffce..c4076a0120 100644
--- a/phpBB/includes/bbcode.php
+++ b/phpBB/includes/bbcode.php
@@ -126,13 +126,13 @@ class bbcode
 	*/
 	function bbcode_cache_init()
 	{
-		global $phpbb_root_path, $phpEx, $config, $user, $phpbb_extension_manager, $phpbb_filesystem;
+		global $phpbb_root_path, $phpEx, $config, $user, $phpbb_extension_manager, $phpbb_path_helper;
 
 		if (empty($this->template_filename))
 		{
 			$this->template_bitfield = new bitfield($user->style['bbcode_bitfield']);
 
-			$template = new phpbb\template\twig\twig($phpbb_filesystem, $config, $user, new phpbb\template\context(), $phpbb_extension_manager);
+			$template = new phpbb\template\twig\twig($phpbb_path_helper, $config, $user, new phpbb\template\context(), $phpbb_extension_manager);
 			$template->set_style();
 			$template->set_filenames(array('bbcode.html' => 'bbcode.html'));
 			$this->template_filename = $template->get_source_file_for_handle('bbcode.html');
diff --git a/phpBB/includes/functions.php b/phpBB/includes/functions.php
index c49c1d809b..953c0a3b1c 100644
--- a/phpBB/includes/functions.php
+++ b/phpBB/includes/functions.php
@@ -1025,31 +1025,32 @@ else
 */
 function phpbb_clean_path($path)
 {
-	global $phpbb_container;
+	global $phpbb_path_helper, $phpbb_container;
 
-	if ($phpbb_container)
+	if (!$phpbb_path_helper && $phpbb_container)
 	{
-		$phpbb_filesystem = $phpbb_container->get('filesystem');
+		$phpbb_path_helper = $phpbb_container->get('path_helper');
 	}
-	else
+	else if (!$phpbb_path_helper)
 	{
 		// The container is not yet loaded, use a new instance
-		if (!class_exists('\phpbb\filesystem'))
+		if (!class_exists('\phpbb\path_helper'))
 		{
 			global $phpbb_root_path, $phpEx;
-			require($phpbb_root_path . 'includes/filesystem.' . $phpEx);
+			require($phpbb_root_path . 'phpbb/path_helper.' . $phpEx);
 		}
 
-		$phpbb_filesystem = new phpbb\filesystem(
+		$phpbb_path_helper = new phpbb\path_helper(
 			new phpbb\symfony_request(
 				new phpbb\request\request()
 			),
+			new phpbb\filesystem(),
 			$phpbb_root_path,
 			$phpEx
 		);
 	}
 
-	return $phpbb_filesystem->clean_path($path);
+	return $phpbb_path_helper->clean_path($path);
 }
 
 // functions used for building option fields
@@ -2414,7 +2415,7 @@ function phpbb_on_page($template, $user, $base_url, $num_items, $per_page, $star
 */
 function append_sid($url, $params = false, $is_amp = true, $session_id = false)
 {
-	global $_SID, $_EXTRA_URL, $phpbb_hook, $phpbb_filesystem;
+	global $_SID, $_EXTRA_URL, $phpbb_hook, $phpbb_path_helper;
 	global $phpbb_dispatcher;
 
 	if ($params === '' || (is_array($params) && empty($params)))
@@ -2424,9 +2425,9 @@ function append_sid($url, $params = false, $is_amp = true, $session_id = false)
 	}
 
 	// Update the root path with the correct relative web path
-	if ($phpbb_filesystem instanceof \phpbb\filesystem)
+	if ($phpbb_path_helper instanceof \phpbb\path_helper)
 	{
-		$url = $phpbb_filesystem->update_web_root_path($url);
+		$url = $phpbb_path_helper->update_web_root_path($url);
 	}
 
 	$append_sid_overwrite = false;
@@ -5245,8 +5246,8 @@ function page_header($page_title = '', $display_online_list = true, $item_id = 0
 	// This path is sent with the base template paths in the assign_vars()
 	// call below. We need to correct it in case we are accessing from a
 	// controller because the web paths will be incorrect otherwise.
-	$phpbb_filesystem = $phpbb_container->get('filesystem');
-	$corrected_path = $phpbb_filesystem->get_web_root_path();
+	$phpbb_path_helper = $phpbb_container->get('path_helper');
+	$corrected_path = $phpbb_path_helper->get_web_root_path();
 	$web_path = (defined('PHPBB_USE_BOARD_URL_PATH') && PHPBB_USE_BOARD_URL_PATH) ? $board_url : $corrected_path;
 
 	// Send a proper content-language to the output
diff --git a/phpBB/includes/functions_content.php b/phpBB/includes/functions_content.php
index 7ecc99b39c..863450a4b2 100644
--- a/phpBB/includes/functions_content.php
+++ b/phpBB/includes/functions_content.php
@@ -834,7 +834,7 @@ function bbcode_nl2br($text)
 */
 function smiley_text($text, $force_option = false)
 {
-	global $config, $user, $phpbb_filesystem;
+	global $config, $user, $phpbb_path_helper;
 
 	if ($force_option || !$config['allow_smilies'] || !$user->optionget('viewsmilies'))
 	{
@@ -842,7 +842,7 @@ function smiley_text($text, $force_option = false)
 	}
 	else
 	{
-		$root_path = (defined('PHPBB_USE_BOARD_URL_PATH') && PHPBB_USE_BOARD_URL_PATH) ? generate_board_url() . '/' : $phpbb_filesystem->get_web_root_path();
+		$root_path = (defined('PHPBB_USE_BOARD_URL_PATH') && PHPBB_USE_BOARD_URL_PATH) ? generate_board_url() . '/' : $phpbb_path_helper->get_web_root_path();
 		return preg_replace('#<!\-\- s(.*?) \-\-><img src="\{SMILIES_PATH\}\/(.*?) \/><!\-\- s\1 \-\->#', '<img class="smilies" src="' . $root_path . $config['smilies_path'] . '/\2 />', $text);
 	}
 }
diff --git a/phpBB/includes/functions_messenger.php b/phpBB/includes/functions_messenger.php
index f8b01bc770..5b343e616e 100644
--- a/phpBB/includes/functions_messenger.php
+++ b/phpBB/includes/functions_messenger.php
@@ -626,14 +626,14 @@ class messenger
 	*/
 	protected function setup_template()
 	{
-		global $config, $phpbb_filesystem, $user, $phpbb_extension_manager;
+		global $config, $phpbb_path_helper, $user, $phpbb_extension_manager;
 
 		if ($this->template instanceof \phpbb\template\template)
 		{
 			return;
 		}
 
-		$this->template = new \phpbb\template\twig\twig($phpbb_filesystem, $config, $user, new \phpbb\template\context(), $phpbb_extension_manager);
+		$this->template = new \phpbb\template\twig\twig($phpbb_path_helper, $config, $user, new \phpbb\template\context(), $phpbb_extension_manager);
 	}
 
 	/**
diff --git a/phpBB/includes/functions_user.php b/phpBB/includes/functions_user.php
index c248be0864..0a0656377c 100644
--- a/phpBB/includes/functions_user.php
+++ b/phpBB/includes/functions_user.php
@@ -388,12 +388,13 @@ function user_delete($mode, $user_ids, $retain_username = true)
 	* Event before a user is deleted
 	*
 	* @event core.delete_user_before
-	* @var	string	mode			Mode of deletion (retain/delete posts)
-	* @var	int		user_id			ID of the deleted user
-	* @var	mixed	post_username	Guest username that is being used or false
+	* @var	string	mode		Mode of deletion (retain/delete posts)
+	* @var	array	user_ids	IDs of the deleted user
+	* @var	mixed	retain_username	True if username should be retained
+	*				or false if not
 	* @since 3.1-A1
 	*/
-	$vars = array('mode', 'user_id', 'post_username');
+	$vars = array('mode', 'user_ids', 'retain_username');
 	extract($phpbb_dispatcher->trigger_event('core.delete_user_before', compact($vars)));
 
 	// Before we begin, we will remove the reports the user issued.
@@ -616,12 +617,13 @@ function user_delete($mode, $user_ids, $retain_username = true)
 	* Event after a user is deleted
 	*
 	* @event core.delete_user_after
-	* @var	string	mode			Mode of deletion (retain/delete posts)
-	* @var	int		user_id			ID of the deleted user
-	* @var	mixed	post_username	Guest username that is being used or false
+	* @var	string	mode		Mode of deletion (retain/delete posts)
+	* @var	array	user_ids	IDs of the deleted user
+	* @var	mixed	retain_username	True if username should be retained
+	*				or false if not
 	* @since 3.1-A1
 	*/
-	$vars = array('mode', 'user_id', 'post_username');
+	$vars = array('mode', 'user_ids', 'retain_username');
 	extract($phpbb_dispatcher->trigger_event('core.delete_user_after', compact($vars)));
 
 	// Reset newest user info if appropriate
diff --git a/phpBB/install/index.php b/phpBB/install/index.php
index 2a3bb36bf6..161dc78173 100644
--- a/phpBB/install/index.php
+++ b/phpBB/install/index.php
@@ -244,8 +244,8 @@ $config = new \phpbb\config\config(array(
 	'load_tplcompile'	=> '1'
 ));
 
-$phpbb_filesystem = $phpbb_container->get('filesystem');
-$template = new \phpbb\template\twig\twig($phpbb_filesystem, $config, $user, new \phpbb\template\context());
+$phpbb_path_helper = $phpbb_container->get('path_helper');
+$template = new \phpbb\template\twig\twig($phpbb_path_helper, $config, $user, new \phpbb\template\context());
 $paths = array($phpbb_root_path . 'install/update/new/adm/style', $phpbb_admin_path . 'style');
 $paths = array_filter($paths, 'is_dir');
 $template->set_custom_style('adm', $paths);
diff --git a/phpBB/phpbb/db/migration/data/v310/notification_options_reconvert.php b/phpBB/phpbb/db/migration/data/v310/notification_options_reconvert.php
index bd7614e1c2..4195623618 100644
--- a/phpBB/phpbb/db/migration/data/v310/notification_options_reconvert.php
+++ b/phpBB/phpbb/db/migration/data/v310/notification_options_reconvert.php
@@ -19,35 +19,44 @@ class notification_options_reconvert extends \phpbb\db\migration\migration
 	public function update_data()
 	{
 		return array(
+			array('custom', array(array($this, 'purge_notifications'))),
 			array('custom', array(array($this, 'convert_notifications'))),
 		);
 	}
 
-	public function convert_notifications()
+	public function purge_notifications()
 	{
-		$insert_table = $this->table_prefix . 'user_notifications';
-		$insert_buffer = new \phpbb\db\sql_insert_buffer($this->db, $insert_table);
+		$sql = 'DELETE FROM ' . $this->table_prefix . 'user_notifications';
+		$this->sql_query($sql);
+	}
 
-		$this->perform_conversion($insert_buffer, $insert_table);
+	public function convert_notifications($start)
+	{
+		$insert_buffer = new \phpbb\db\sql_insert_buffer($this->db, $this->table_prefix . 'user_notifications');
+
+		return $this->perform_conversion($insert_buffer, $start);
 	}
 
 	/**
 	* Perform the conversion (separate for testability)
 	*
-	* @param \phpbb\db\sql_insert_buffer $insert_buffer
-	* @param string $insert_table
+	* @param \phpbb\db\sql_insert_buffer		$insert_buffer
+	* @param int			$start		Start of staggering step
+	* @return		mixed		int start of the next step, null if the end was reached
 	*/
-	public function perform_conversion(\phpbb\db\sql_insert_buffer $insert_buffer, $insert_table)
+	public function perform_conversion(\phpbb\db\sql_insert_buffer $insert_buffer, $start)
 	{
-		$sql = 'DELETE FROM ' . $insert_table;
-		$this->db->sql_query($sql);
+		$limit = 250;
+		$converted_users = 0;
 
 		$sql = 'SELECT user_id, user_notify_type, user_notify_pm
-			FROM ' . USERS_TABLE;
-		$result = $this->db->sql_query($sql);
+			FROM ' . $this->table_prefix . 'users
+			ORDER BY user_id';
+		$result = $this->db->sql_query_limit($sql, $limit, $start);
 
 		while ($row = $this->db->sql_fetchrow($result))
 		{
+			$converted_users++;
 			$notification_methods = array();
 
 			// In-board notification
@@ -91,6 +100,14 @@ class notification_options_reconvert extends \phpbb\db\migration\migration
 		$this->db->sql_freeresult($result);
 
 		$insert_buffer->flush();
+
+		if ($converted_users < $limit)
+		{
+			// No more users left, we are done...
+			return;
+		}
+
+		return $start + $limit;
 	}
 
 	/**
diff --git a/phpBB/phpbb/db/migration/data/v310/softdelete_mcp_modules.php b/phpBB/phpbb/db/migration/data/v310/softdelete_mcp_modules.php
index 2db9780601..d1a31815b2 100644
--- a/phpBB/phpbb/db/migration/data/v310/softdelete_mcp_modules.php
+++ b/phpBB/phpbb/db/migration/data/v310/softdelete_mcp_modules.php
@@ -28,8 +28,8 @@ class softdelete_mcp_modules extends \phpbb\db\migration\migration
 	static public function depends_on()
 	{
 		return array(
-			'phpbb\db\migration\data\v310\dev',
-			'phpbb\db\migration\data\v310\softdelete_p2',
+			'\phpbb\db\migration\data\v310\dev',
+			'\phpbb\db\migration\data\v310\softdelete_p2',
 		);
 	}
 
diff --git a/phpBB/phpbb/db/migration/data/v310/softdelete_p1.php b/phpBB/phpbb/db/migration/data/v310/softdelete_p1.php
index 0418d5cc2b..f080c78c50 100644
--- a/phpBB/phpbb/db/migration/data/v310/softdelete_p1.php
+++ b/phpBB/phpbb/db/migration/data/v310/softdelete_p1.php
@@ -101,7 +101,8 @@ class softdelete_p1 extends \phpbb\db\migration\migration
 		return array(
 			array('custom', array(array($this, 'update_post_visibility'))),
 			array('custom', array(array($this, 'update_topic_visibility'))),
-			array('custom', array(array($this, 'update_topic_forum_counts'))),
+			array('custom', array(array($this, 'update_topics_post_counts'))),
+			array('custom', array(array($this, 'update_forums_topic_and_post_counts'))),
 
 			array('permission.add', array('f_softdelete', false)),
 			array('permission.add', array('m_softdelete', false)),
@@ -122,28 +123,43 @@ class softdelete_p1 extends \phpbb\db\migration\migration
 		$this->sql_query($sql);
 	}
 
-	public function update_topic_forum_counts()
+	public function update_topics_post_counts()
 	{
+		/*
+		* Using sql_case here to avoid "BIGINT UNSIGNED value is out of range" errors.
+		* As we update all topics in 2 queries, one broken topic would stop the conversion
+		* for all topics and the surpressed error will cause the admin to not even notice it.
+		*/
 		$sql = 'UPDATE ' . $this->table_prefix . 'topics
 			SET topic_posts_approved = topic_replies + 1,
-				topic_posts_unapproved = topic_replies_real - topic_replies
+				topic_posts_unapproved = ' . $this->db->sql_case('topic_replies_real > topic_replies', 'topic_replies_real - topic_replies', '0') . '
 			WHERE topic_visibility = ' . ITEM_APPROVED;
 		$this->sql_query($sql);
 
 		$sql = 'UPDATE ' . $this->table_prefix . 'topics
 			SET topic_posts_approved = 0,
-				topic_posts_unapproved = (topic_replies_real - topic_replies) + 1
+				topic_posts_unapproved = (' . $this->db->sql_case('topic_replies_real > topic_replies', 'topic_replies_real - topic_replies', '0') . ') + 1
 			WHERE topic_visibility = ' . ITEM_UNAPPROVED;
 		$this->sql_query($sql);
+	}
+
+	public function update_forums_topic_and_post_counts($start)
+	{
+		$start = (int) $start;
+		$limit = 10;
+		$converted_forums = 0;
 
 		$sql = 'SELECT forum_id, topic_visibility, COUNT(topic_id) AS sum_topics, SUM(topic_posts_approved) AS sum_posts_approved, SUM(topic_posts_unapproved) AS sum_posts_unapproved
 			FROM ' . $this->table_prefix . 'topics
-			GROUP BY forum_id, topic_visibility';
-		$result = $this->db->sql_query($sql);
+			GROUP BY forum_id, topic_visibility
+			ORDER BY forum_id, topic_visibility';
+		$result = $this->db->sql_query_limit($sql, $limit, $start);
 
 		$update_forums = array();
 		while ($row = $this->db->sql_fetchrow($result))
 		{
+			$converted_forums++;
+
 			$forum_id = (int) $row['forum_id'];
 			if (!isset($update_forums[$forum_id]))
 			{
@@ -169,5 +185,14 @@ class softdelete_p1 extends \phpbb\db\migration\migration
 				WHERE forum_id = ' . $forum_id;
 			$this->sql_query($sql);
 		}
+
+		if ($converted_forums < $limit)
+		{
+			// There are no more topics, we are done
+			return;
+		}
+
+		// There are still more topics to query, return the next start value
+		return $start + $limit;
 	}
 }
diff --git a/phpBB/phpbb/db/migrator.php b/phpBB/phpbb/db/migrator.php
index d7d2b3df59..7efb23a230 100644
--- a/phpBB/phpbb/db/migrator.php
+++ b/phpBB/phpbb/db/migrator.php
@@ -208,7 +208,7 @@ class migrator
 
 		if (!isset($this->migration_state[$name]))
 		{
-			if ($migration->effectively_installed())
+			if ($state['migration_start_time'] == 0 && $migration->effectively_installed())
 			{
 				$state = array(
 					'migration_depends_on'	=> $migration->depends_on(),
@@ -227,6 +227,8 @@ class migrator
 			}
 		}
 
+		$this->set_migration_state($name, $state);
+
 		if (!$state['migration_schema_done'])
 		{
 			$this->apply_schema_changes($migration->update_schema());
diff --git a/phpBB/phpbb/filesystem.php b/phpBB/phpbb/filesystem.php
index 662b6b866e..dbfaebe0fa 100644
--- a/phpBB/phpbb/filesystem.php
+++ b/phpBB/phpbb/filesystem.php
@@ -23,151 +23,6 @@ if (!defined('IN_PHPBB'))
 */
 class filesystem
 {
-	/** @var \phpbb\symfony_request */
-	protected $symfony_request;
-
-	/** @var string */
-	protected $phpbb_root_path;
-
-	/** @var string */
-	protected $adm_relative_path;
-
-	/** @var string */
-	protected $php_ext;
-
-	/** @var string */
-	protected $web_root_path;
-
-	/**
-	* Constructor
-	*
-	* @param \phpbb\symfony_request $symfony_request
-	* @param string $phpbb_root_path Relative path to phpBB root
-	* @param string $php_ext PHP extension (php)
-	*/
-	public function __construct(\phpbb\symfony_request $symfony_request, $phpbb_root_path, $php_ext, $adm_relative_path = null)
-	{
-		$this->symfony_request = $symfony_request;
-		$this->phpbb_root_path = $phpbb_root_path;
-		$this->php_ext = $php_ext;
-		$this->adm_relative_path = $adm_relative_path;
-	}
-
-	/**
-	* Get the phpBB root path
-	*
-	* @return string
-	*/
-	public function get_phpbb_root_path()
-	{
-		return $this->phpbb_root_path;
-	}
-
-	/**
-	* Get the adm root path
-	*
-	* @return string
-	*/
-	public function get_adm_relative_path()
-	{
-		return $this->adm_relative_path;
-	}
-
-	/**
-	* Get the php extension
-	*
-	* @return string
-	*/
-	public function get_php_ext()
-	{
-		return $this->php_ext;
-	}
-
-	/**
-	* Update a path to the correct relative root path
-	*
-	* This replaces $phpbb_root_path . some_url with
-	*	get_web_root_path() . some_url OR if $phpbb_root_path
-	*	is not at the beginning of $path, just prepends the
-	*	web root path
-	*
-	* @param string $path The path to be updated
-	* @return string
-	*/
-	public function update_web_root_path($path)
-	{
-		$web_root_path = $this->get_web_root_path($this->symfony_request);
-
-		if (strpos($path, $this->phpbb_root_path) === 0)
-		{
-			$path = substr($path, strlen($this->phpbb_root_path));
-		}
-
-		return $web_root_path . $path;
-	}
-
-	/**
-	* Get a relative root path from the current URL
-	*
-	* @return string
-	*/
-	public function get_web_root_path()
-	{
-		if ($this->symfony_request === null)
-		{
-			return $this->phpbb_root_path;
-		}
-
-		if (null !== $this->web_root_path)
-		{
-			return $this->web_root_path;
-		}
-
-		// Path info (e.g. /foo/bar)
-		$path_info = $this->clean_path($this->symfony_request->getPathInfo());
-
-		// Full request URI (e.g. phpBB/app.php/foo/bar)
-		$request_uri = $this->symfony_request->getRequestUri();
-
-		// Script name URI (e.g. phpBB/app.php)
-		$script_name = $this->symfony_request->getScriptName();
-
-		/*
-		* If the path info is empty (single /), then we're not using
-		*	a route like app.php/foo/bar
-		*/
-		if ($path_info === '/')
-		{
-			return $this->web_root_path = $this->phpbb_root_path;
-		}
-
-		// How many corrections might we need?
-		$corrections = substr_count($path_info, '/');
-
-		/*
-		* If the script name (e.g. phpBB/app.php) exists in the
-		*	requestUri (e.g. phpBB/app.php/foo/template), then we
-		*	are have a non-rewritten URL.
-		*/
-		if (strpos($request_uri, $script_name) === 0)
-		{
-			/*
-			* Append ../ to the end of the phpbb_root_path as many times
-			*	as / exists in path_info
-			*/
-			return $this->web_root_path = $this->phpbb_root_path . str_repeat('../', $corrections);
-		}
-
-		/*
-		* If we're here it means we're at a re-written path, so we must
-		*	correct the relative path for web URLs. We must append ../
-		*	to the end of the root path as many times as / exists in path_info
-		*	less one time (because the script, e.g. /app.php, doesn't exist in
-		*	the URL)
-		*/
-		return $this->web_root_path = $this->phpbb_root_path . str_repeat('../', $corrections - 1);
-	}
-
 	/**
 	* Eliminates useless . and .. components from specified path.
 	*
diff --git a/phpBB/phpbb/path_helper.php b/phpBB/phpbb/path_helper.php
new file mode 100644
index 0000000000..b2ed11a927
--- /dev/null
+++ b/phpBB/phpbb/path_helper.php
@@ -0,0 +1,175 @@
+<?php
+/**
+*
+* @package phpBB3
+* @copyright (c) 2013 phpBB Group
+* @license http://opensource.org/licenses/gpl-2.0.php GNU General Public License v2
+*
+*/
+
+namespace phpbb;
+
+/**
+* @ignore
+*/
+if (!defined('IN_PHPBB'))
+{
+	exit;
+}
+
+/**
+* A class with various functions that are related to paths, files and the filesystem
+* @package phpBB3
+*/
+class path_helper
+{
+	/** @var \phpbb\symfony_request */
+	protected $symfony_request;
+
+	/** @var \phpbb\filesystem */
+	protected $filesystem;
+
+	/** @var string */
+	protected $phpbb_root_path;
+
+	/** @var string */
+	protected $adm_relative_path;
+
+	/** @var string */
+	protected $php_ext;
+
+	/** @var string */
+	protected $web_root_path;
+
+	/**
+	* Constructor
+	*
+	* @param \phpbb\symfony_request $symfony_request
+	* @param \phpbb\filesystem $filesystem
+	* @param string $phpbb_root_path Relative path to phpBB root
+	* @param string $php_ext PHP extension (php)
+	*/
+	public function __construct(\phpbb\symfony_request $symfony_request, \phpbb\filesystem $filesystem, $phpbb_root_path, $php_ext, $adm_relative_path = null)
+	{
+		$this->symfony_request = $symfony_request;
+		$this->filesystem = $filesystem;
+		$this->phpbb_root_path = $phpbb_root_path;
+		$this->php_ext = $php_ext;
+		$this->adm_relative_path = $adm_relative_path;
+	}
+
+	/**
+	* Get the phpBB root path
+	*
+	* @return string
+	*/
+	public function get_phpbb_root_path()
+	{
+		return $this->phpbb_root_path;
+	}
+
+	/**
+	* Get the adm root path
+	*
+	* @return string
+	*/
+	public function get_adm_relative_path()
+	{
+		return $this->adm_relative_path;
+	}
+
+	/**
+	* Get the php extension
+	*
+	* @return string
+	*/
+	public function get_php_ext()
+	{
+		return $this->php_ext;
+	}
+
+	/**
+	* Update a path to the correct relative root path
+	*
+	* This replaces $phpbb_root_path . some_url with
+	*	get_web_root_path() . some_url OR if $phpbb_root_path
+	*	is not at the beginning of $path, just prepends the
+	*	web root path
+	*
+	* @param string $path The path to be updated
+	* @return string
+	*/
+	public function update_web_root_path($path)
+	{
+		$web_root_path = $this->get_web_root_path($this->symfony_request);
+
+		if (strpos($path, $this->phpbb_root_path) === 0)
+		{
+			$path = substr($path, strlen($this->phpbb_root_path));
+		}
+
+		return $web_root_path . $path;
+	}
+
+	/**
+	* Get a relative root path from the current URL
+	*
+	* @return string
+	*/
+	public function get_web_root_path()
+	{
+		if ($this->symfony_request === null)
+		{
+			return $this->phpbb_root_path;
+		}
+
+		if (null !== $this->web_root_path)
+		{
+			return $this->web_root_path;
+		}
+
+		// Path info (e.g. /foo/bar)
+		$path_info = $this->filesystem->clean_path($this->symfony_request->getPathInfo());
+
+		// Full request URI (e.g. phpBB/app.php/foo/bar)
+		$request_uri = $this->symfony_request->getRequestUri();
+
+		// Script name URI (e.g. phpBB/app.php)
+		$script_name = $this->symfony_request->getScriptName();
+
+		/*
+		* If the path info is empty (single /), then we're not using
+		*	a route like app.php/foo/bar
+		*/
+		if ($path_info === '/')
+		{
+			return $this->web_root_path = $this->phpbb_root_path;
+		}
+
+		// How many corrections might we need?
+		$corrections = substr_count($path_info, '/');
+
+		/*
+		* If the script name (e.g. phpBB/app.php) exists in the
+		*	requestUri (e.g. phpBB/app.php/foo/template), then we
+		*	are have a non-rewritten URL.
+		*/
+		if (strpos($request_uri, $script_name) === 0)
+		{
+			/*
+			* Append ../ to the end of the phpbb_root_path as many times
+			*	as / exists in path_info
+			*/
+			return $this->web_root_path = $this->phpbb_root_path . str_repeat('../', $corrections);
+		}
+
+		/*
+		* If we're here it means we're at a re-written path, so we must
+		*	correct the relative path for web URLs. We must append ../
+		*	to the end of the root path as many times as / exists in path_info
+		*	less one time (because the script, e.g. /app.php, doesn't exist in
+		*	the URL)
+		*/
+		return $this->web_root_path = $this->phpbb_root_path . str_repeat('../', $corrections - 1);
+	}
+}
diff --git a/phpBB/phpbb/template/asset.php b/phpBB/phpbb/template/asset.php
index 0e0b6b4782..27564bf347 100644
--- a/phpBB/phpbb/template/asset.php
+++ b/phpBB/phpbb/template/asset.php
@@ -21,17 +21,17 @@ class asset
 {
 	protected $components = array();
 
-	/** @var \phpbb\filesystem **/
-	protected $phpbb_filesystem;
+	/** @var \phpbb\path_helper **/
+	protected $path_helper;
 
 	/**
 	* Constructor
 	*
 	* @param string $url URL
 	*/
-	public function __construct($url, \phpbb\filesystem $phpbb_filesystem)
+	public function __construct($url, \phpbb\path_helper $path_helper)
 	{
-		$this->phpbb_filesystem = $phpbb_filesystem;
+		$this->path_helper = $path_helper;
 
 		$this->set_url($url);
 	}
@@ -119,7 +119,7 @@ class asset
 	*/
 	public function get_url()
 	{
-		return $this->phpbb_filesystem->update_web_root_path($this->join_url($this->components));
+		return $this->path_helper->update_web_root_path($this->join_url($this->components));
 	}
 
 	/**
diff --git a/phpBB/phpbb/template/twig/environment.php b/phpBB/phpbb/template/twig/environment.php
index e0ee23dcd9..a6c0e476f0 100644
--- a/phpBB/phpbb/template/twig/environment.php
+++ b/phpBB/phpbb/template/twig/environment.php
@@ -25,8 +25,8 @@ class environment extends \Twig_Environment
 	/** @var \phpbb\config\config */
 	protected $phpbb_config;
 
-	/** @var \phpbb\filesystem */
-	protected $phpbb_filesystem;
+	/** @var \phpbb\path_helper */
+	protected $phpbb_path_helper;
 
 	/** @var string */
 	protected $phpbb_root_path;
@@ -42,19 +42,19 @@ class environment extends \Twig_Environment
 	*
 	* @param \phpbb\config\config $phpbb_config
 	* @param array $phpbb_extensions Array of enabled extensions (name => path)
-	* @param \phpbb\filesystem
+	* @param \phpbb\path_helper
 	* @param string $phpbb_root_path
 	* @param Twig_LoaderInterface $loader
 	* @param array $options Array of options to pass to Twig
 	*/
-	public function __construct($phpbb_config, $phpbb_extensions, \phpbb\filesystem $phpbb_filesystem, \Twig_LoaderInterface $loader = null, $options = array())
+	public function __construct($phpbb_config, $phpbb_extensions, \phpbb\path_helper $path_helper, \Twig_LoaderInterface $loader = null, $options = array())
 	{
 		$this->phpbb_config = $phpbb_config;
 		$this->phpbb_extensions = $phpbb_extensions;
 
-		$this->phpbb_filesystem = $phpbb_filesystem;
-		$this->phpbb_root_path = $this->phpbb_filesystem->get_phpbb_root_path();
-		$this->web_root_path = $this->phpbb_filesystem->get_web_root_path();
+		$this->phpbb_path_helper = $path_helper;
+		$this->phpbb_root_path = $this->phpbb_path_helper->get_phpbb_root_path();
+		$this->web_root_path = $this->phpbb_path_helper->get_web_root_path();
 
 		return parent::__construct($loader, $options);
 	}
@@ -102,13 +102,13 @@ class environment extends \Twig_Environment
 	}
 
 	/**
-	* Get the phpbb_filesystem object
+	* Get the phpbb path helper object
 	*
-	* @return \phpbb\filesystem
+	* @return \phpbb\path_helper
 	*/
-	public function get_filesystem()
+	public function get_path_helper()
 	{
-		return $this->phpbb_filesystem;
+		return $this->phpbb_path_helper;
 	}
 
 	/**
diff --git a/phpBB/phpbb/template/twig/node/includeasset.php b/phpBB/phpbb/template/twig/node/includeasset.php
index f15fd6296b..f6c9dc9c58 100644
--- a/phpBB/phpbb/template/twig/node/includeasset.php
+++ b/phpBB/phpbb/template/twig/node/includeasset.php
@@ -35,7 +35,7 @@ abstract class includeasset extends \Twig_Node
 			->write("\$asset_file = ")
 			->subcompile($this->getNode('expr'))
 			->raw(";\n")
-			->write("\$asset = new \phpbb\\template\\asset(\$asset_file, \$this->getEnvironment()->get_filesystem());\n")
+			->write("\$asset = new \phpbb\\template\\asset(\$asset_file, \$this->getEnvironment()->get_path_helper());\n")
 			->write("if (substr(\$asset_file, 0, 2) !== './' && \$asset->is_relative()) {\n")
 			->indent()
 				->write("\$asset_path = \$asset->get_path();")
diff --git a/phpBB/phpbb/template/twig/twig.php b/phpBB/phpbb/template/twig/twig.php
index 2da7405743..9df9310427 100644
--- a/phpBB/phpbb/template/twig/twig.php
+++ b/phpBB/phpbb/template/twig/twig.php
@@ -33,10 +33,10 @@ class twig extends \phpbb\template\base
 	private $cachepath = '';
 
 	/**
-	* phpBB filesystem
-	* @var \phpbb\filesystem
+	* phpBB path helper
+	* @var \phpbb\path_helper
 	*/
-	protected $phpbb_filesystem;
+	protected $path_helper;
 
 	/**
 	* phpBB root path
@@ -79,17 +79,17 @@ class twig extends \phpbb\template\base
 	/**
 	* Constructor.
 	*
-	* @param \phpbb\filesystem $phpbb_filesystem
+	* @param \phpbb\path_helper $path_helper
 	* @param \phpbb\config\config $config
 	* @param \phpbb\user $user
 	* @param \phpbb\template\context $context template context
 	* @param \phpbb\extension\manager $extension_manager extension manager, if null then template events will not be invoked
 	*/
-	public function __construct(\phpbb\filesystem $phpbb_filesystem, $config, $user, \phpbb\template\context $context, \phpbb\extension\manager $extension_manager = null)
+	public function __construct(\phpbb\path_helper $path_helper, $config, $user, \phpbb\template\context $context, \phpbb\extension\manager $extension_manager = null)
 	{
-		$this->phpbb_filesystem = $phpbb_filesystem;
-		$this->phpbb_root_path = $phpbb_filesystem->get_phpbb_root_path();
-		$this->php_ext = $phpbb_filesystem->get_php_ext();
+		$this->path_helper = $path_helper;
+		$this->phpbb_root_path = $path_helper->get_phpbb_root_path();
+		$this->php_ext = $path_helper->get_php_ext();
 		$this->config = $config;
 		$this->user = $user;
 		$this->context = $context;
@@ -103,7 +103,7 @@ class twig extends \phpbb\template\base
 		$this->twig = new \phpbb\template\twig\environment(
 			$this->config,
 			($this->extension_manager) ? $this->extension_manager->all_enabled() : array(),
-			$this->phpbb_filesystem,
+			$this->path_helper,
 			$loader,
 			array(
 				'cache'			=> (defined('IN_INSTALL')) ? false : $this->cachepath,
@@ -125,9 +125,9 @@ class twig extends \phpbb\template\base
 		$this->twig->setLexer($lexer);
 
 		// Add admin namespace
-		if ($this->phpbb_filesystem->get_adm_relative_path() !== null && is_dir($this->phpbb_root_path . $this->phpbb_filesystem->get_adm_relative_path() . 'style/'))
+		if ($this->path_helper->get_adm_relative_path() !== null && is_dir($this->phpbb_root_path . $this->path_helper->get_adm_relative_path() . 'style/'))
 		{
-			$this->twig->getLoader()->setPaths($this->phpbb_root_path . $this->phpbb_filesystem->get_adm_relative_path() . 'style/', 'admin');
+			$this->twig->getLoader()->setPaths($this->phpbb_root_path . $this->path_helper->get_adm_relative_path() . 'style/', 'admin');
 		}
 	}
 
diff --git a/tests/controller/helper_url_test.php b/tests/controller/helper_url_test.php
index 4ea177074f..33fc6c4f1b 100644
--- a/tests/controller/helper_url_test.php
+++ b/tests/controller/helper_url_test.php
@@ -49,14 +49,15 @@ class phpbb_controller_helper_url_test extends phpbb_test_case
 
 		$phpbb_dispatcher = new phpbb_mock_event_dispatcher;
 		$this->user = $this->getMock('\phpbb\user');
-		$phpbb_filesystem = new \phpbb\filesystem(
+		$phpbb_path_helper = new \phpbb\path_helper(
 			new \phpbb\symfony_request(
 				new phpbb_mock_request()
 			),
+			new \phpbb\filesystem(),
 			$phpbb_root_path,
 			$phpEx
 		);
-		$this->template = new phpbb\template\twig\twig($phpbb_filesystem, $config, $this->user, new \phpbb\template\context());
+		$this->template = new phpbb\template\twig\twig($phpbb_path_helper, $config, $this->user, new \phpbb\template\context());
 
 		// We don't use mod_rewrite in these tests
 		$config = new \phpbb\config\config(array('enable_mod_rewrite' => '0'));
@@ -101,14 +102,15 @@ class phpbb_controller_helper_url_test extends phpbb_test_case
 
 		$phpbb_dispatcher = new phpbb_mock_event_dispatcher;
 		$this->user = $this->getMock('\phpbb\user');
-		$phpbb_filesystem = new \phpbb\filesystem(
+		$phpbb_path_helper = new \phpbb\path_helper(
 			new \phpbb\symfony_request(
 				new phpbb_mock_request()
 			),
+			new \phpbb\filesystem(),
 			$phpbb_root_path,
 			$phpEx
 		);
-		$this->template = new \phpbb\template\twig\twig($phpbb_filesystem, $config, $this->user, new \phpbb\template\context());
+		$this->template = new \phpbb\template\twig\twig($phpbb_path_helper, $config, $this->user, new \phpbb\template\context());
 
 		$config = new \phpbb\config\config(array('enable_mod_rewrite' => '1'));
 		$helper = new \phpbb\controller\helper($this->template, $this->user, $config, '', 'php');
diff --git a/tests/dbal/migrator_test.php b/tests/dbal/migrator_test.php
index ef5d167fc2..c6b4c289d3 100644
--- a/tests/dbal/migrator_test.php
+++ b/tests/dbal/migrator_test.php
@@ -59,13 +59,7 @@ class phpbb_dbal_migrator_test extends phpbb_database_test_case
 			$container,
 			$this->db,
 			$this->config,
-			new phpbb\filesystem(
-				new phpbb\symfony_request(
-					new phpbb_mock_request()
-				),
-				dirname(__FILE__) . '/../../phpBB/',
-				'php'
-			),
+			new phpbb\filesystem(),
 			'phpbb_ext',
 			dirname(__FILE__) . '/../../phpBB/',
 			'php',
diff --git a/tests/extension/manager_test.php b/tests/extension/manager_test.php
index c4a32f53ab..b127daf2ed 100644
--- a/tests/extension/manager_test.php
+++ b/tests/extension/manager_test.php
@@ -114,13 +114,7 @@ class phpbb_extension_manager_test extends phpbb_database_test_case
 			$container,
 			$db,
 			$config,
-			new \phpbb\filesystem(
-				new \phpbb\symfony_request(
-					new phpbb_mock_request()
-				),
-				$phpbb_root_path,
-				$php_ext
-			),
+			new \phpbb\filesystem(),
 			'phpbb_ext',
 			dirname(__FILE__) . '/',
 			$php_ext,
diff --git a/tests/extension/metadata_manager_test.php b/tests/extension/metadata_manager_test.php
index 2b27a1bae2..242ec38908 100644
--- a/tests/extension/metadata_manager_test.php
+++ b/tests/extension/metadata_manager_test.php
@@ -41,10 +41,11 @@ class phpbb_extension_metadata_manager_test extends phpbb_database_test_case
 		$this->table_prefix = 'phpbb_';
 
 		$this->template = new \phpbb\template\twig\twig(
-			new \phpbb\filesystem(
+			new \phpbb\path_helper(
 				new \phpbb\symfony_request(
 					new phpbb_mock_request()
 				),
+				new \phpbb\filesystem(),
 				$this->phpbb_root_path,
 				$this->phpEx
 			),
@@ -70,13 +71,7 @@ class phpbb_extension_metadata_manager_test extends phpbb_database_test_case
 			$container,
 			$this->db,
 			$this->config,
-			new \phpbb\filesystem(
-				new \phpbb\symfony_request(
-					new phpbb_mock_request()
-				),
-				$this->phpbb_root_path,
-				$this->phpEx
-			),
+			new \phpbb\filesystem(),
 			'phpbb_ext',
 			$this->phpbb_root_path,
 			$this->phpEx,
diff --git a/tests/filesystem/clean_path_test.php b/tests/filesystem/clean_path_test.php
index 5b9857ef2c..fedadc103b 100644
--- a/tests/filesystem/clean_path_test.php
+++ b/tests/filesystem/clean_path_test.php
@@ -14,13 +14,7 @@ class phpbb_filesystem_clean_path_test extends phpbb_test_case
 	public function setUp()
 	{
 		parent::setUp();
-		$this->filesystem = new \phpbb\filesystem(
-			new \phpbb\symfony_request(
-				new phpbb_mock_request()
-			),
-			dirname(__FILE__) . './../../phpBB/',
-			'php'
-		);
+		$this->filesystem = new \phpbb\filesystem();
 	}
 
 	public function clean_path_data()
diff --git a/tests/mock/extension_manager.php b/tests/mock/extension_manager.php
index 0c6b8447f1..7049cbdc50 100644
--- a/tests/mock/extension_manager.php
+++ b/tests/mock/extension_manager.php
@@ -14,12 +14,6 @@ class phpbb_mock_extension_manager extends \phpbb\extension\manager
 		$this->phpbb_root_path = $phpbb_root_path;
 		$this->php_ext = 'php';
 		$this->extensions = $extensions;
-		$this->filesystem = new \phpbb\filesystem(
-			new \phpbb\symfony_request(
-				new phpbb_mock_request()
-			),
-			$this->phpbb_root_path,
-			$this->php_ext
-		);
+		$this->filesystem = new \phpbb\filesystem();
 	}
 }
diff --git a/tests/notification/convert_test.php b/tests/notification/convert_test.php
index ed1fa9b1bf..c692f40b57 100644
--- a/tests/notification/convert_test.php
+++ b/tests/notification/convert_test.php
@@ -38,7 +38,7 @@ class phpbb_notification_convert_test extends phpbb_database_test_case
 	public function test_convert()
 	{
 		$buffer = new phpbb_mock_sql_insert_buffer($this->db, 'phpbb_user_notifications');
-		$this->migration->perform_conversion($buffer, 'phpbb_user_notifications');
+		$this->migration->perform_conversion($buffer, 0);
 
 		$expected = array_merge(
 			$this->create_expected('post', 1, 'email'),
diff --git a/tests/filesystem/web_root_path_test.php b/tests/path_helper/web_root_path_test.php
similarity index 85%
rename from tests/filesystem/web_root_path_test.php
rename to tests/path_helper/web_root_path_test.php
index e0f716cdae..938b58892b 100644
--- a/tests/filesystem/web_root_path_test.php
+++ b/tests/path_helper/web_root_path_test.php
@@ -7,9 +7,9 @@
 *
 */
 
-class phpbb_filesystem_web_root_path_test extends phpbb_test_case
+class phpbb_path_helper_web_root_path_test extends phpbb_test_case
 {
-	protected $filesystem;
+	protected $path_helper;
 	protected $phpbb_root_path = '';
 
 	public function setUp()
@@ -18,10 +18,11 @@ class phpbb_filesystem_web_root_path_test extends phpbb_test_case
 
 		$this->set_phpbb_root_path();
 
-		$this->filesystem = new \phpbb\filesystem(
+		$this->path_helper = new \phpbb\path_helper(
 			new \phpbb\symfony_request(
 				new phpbb_mock_request()
 			),
+			new \phpbb\filesystem(),
 			$this->phpbb_root_path,
 			'php'
 		);
@@ -43,7 +44,7 @@ class phpbb_filesystem_web_root_path_test extends phpbb_test_case
 	public function test_get_web_root_path()
 	{
 		// Symfony Request = null, so always should return phpbb_root_path
-		$this->assertEquals($this->phpbb_root_path, $this->filesystem->get_web_root_path());
+		$this->assertEquals($this->phpbb_root_path, $this->path_helper->get_web_root_path());
 	}
 
 	public function basic_update_web_root_path_data()
@@ -71,7 +72,7 @@ class phpbb_filesystem_web_root_path_test extends phpbb_test_case
 	*/
 	public function test_basic_update_web_root_path($input, $expected)
 	{
-		$this->assertEquals($expected, $this->filesystem->update_web_root_path($input, $symfony_request));
+		$this->assertEquals($expected, $this->path_helper->update_web_root_path($input, $symfony_request));
 	}
 
 	public function update_web_root_path_data()
@@ -131,12 +132,13 @@ class phpbb_filesystem_web_root_path_test extends phpbb_test_case
 			->method('getScriptName')
 			->will($this->returnValue($getScriptName));
 
-		$filesystem = new \phpbb\filesystem(
+		$path_helper = new \phpbb\path_helper(
 			$symfony_request,
+			new \phpbb\filesystem(),
 			$this->phpbb_root_path,
 			'php'
 		);
 
-		$this->assertEquals($expected, $filesystem->update_web_root_path($input, $symfony_request));
+		$this->assertEquals($expected, $path_helper->update_web_root_path($input, $symfony_request));
 	}
 }
diff --git a/tests/security/hash_test.php b/tests/security/hash_test.php
index 76d7d22a00..f7d2c0dad8 100644
--- a/tests/security/hash_test.php
+++ b/tests/security/hash_test.php
@@ -44,5 +44,13 @@ class phpbb_security_hash_test extends phpbb_test_case
 		$this->assertTrue(phpbb_check_hash('test', '$P$9isfrtKXWqrz8PvztXlL3.daw4U0zI1'));
 		$this->assertFalse(phpbb_check_hash('foo', '$H$9isfrtKXWqrz8PvztXlL3.daw4U0zI1'));
 	}
+
+	public function test_check_hash_with_large_input()
+	{
+		// 16 MB password, should be rejected quite fast
+		$start_time = time();
+		$this->assertFalse(phpbb_check_hash(str_repeat('a', 1024 * 1024 * 16), '$H$9isfrtKXWqrz8PvztXlL3.daw4U0zI1'));
+		$this->assertLessThanOrEqual(5, time() - $start_time);
+	}
 }
 
diff --git a/tests/template/template_events_test.php b/tests/template/template_events_test.php
index 4155d5fd83..41e00e86a7 100644
--- a/tests/template/template_events_test.php
+++ b/tests/template/template_events_test.php
@@ -116,14 +116,15 @@ Zeta test event in all',
 		$this->extension_manager = new phpbb_mock_filesystem_extension_manager(
 			dirname(__FILE__) . "/datasets/$dataset/"
 		);
-		$phpbb_filesystem = new \phpbb\filesystem(
+		$path_helper = new \phpbb\path_helper(
 			new \phpbb\symfony_request(
 				new phpbb_mock_request()
 			),
+			new \phpbb\filesystem(),
 			$phpbb_root_path,
 			$phpEx
 		);
-		$this->template = new \phpbb\template\twig\twig($phpbb_filesystem, $config, $user, new \phpbb\template\context, $this->extension_manager);
+		$this->template = new \phpbb\template\twig\twig($path_helper, $config, $user, new \phpbb\template\context, $this->extension_manager);
 		$this->template->set_custom_style(((!empty($style_names)) ? $style_names : 'silver'), array($this->template_path));
 	}
 }
diff --git a/tests/template/template_includecss_test.php b/tests/template/template_includecss_test.php
index c00aa8e9bb..7424af0c93 100644
--- a/tests/template/template_includecss_test.php
+++ b/tests/template/template_includecss_test.php
@@ -18,8 +18,8 @@ class phpbb_template_template_includecss_test extends phpbb_template_template_te
 
 		// Prepare correct result
 		$scripts = array(
-			'<link href="' . $this->phpbb_filesystem->get_web_root_path() . 'tests/template/templates/child_only.css?assets_version=1" rel="stylesheet" type="text/css" media="screen, projection" />',
-			'<link href="' . $this->phpbb_filesystem->get_web_root_path() . 'tests/template/parent_templates/parent_only.css?assets_version=1" rel="stylesheet" type="text/css" media="screen, projection" />',
+			'<link href="' . $this->phpbb_path_helper->get_web_root_path() . 'tests/template/templates/child_only.css?assets_version=1" rel="stylesheet" type="text/css" media="screen, projection" />',
+			'<link href="' . $this->phpbb_path_helper->get_web_root_path() . 'tests/template/parent_templates/parent_only.css?assets_version=1" rel="stylesheet" type="text/css" media="screen, projection" />',
 		);
 
 		// Run test
diff --git a/tests/template/template_includejs_test.php b/tests/template/template_includejs_test.php
index 2faeb5fcaa..ab0f4b9ca1 100644
--- a/tests/template/template_includejs_test.php
+++ b/tests/template/template_includejs_test.php
@@ -24,51 +24,51 @@ class phpbb_template_template_includejs_test extends phpbb_template_template_tes
 			*/
 			array(
 				array('TEST' => 1),
-				'<script type="text/javascript" src="' . $this->phpbb_filesystem->get_web_root_path() . 'tests/template/templates/parent_and_child.js?assets_version=1"></script>',
+				'<script type="text/javascript" src="' . $this->phpbb_path_helper->get_web_root_path() . 'tests/template/templates/parent_and_child.js?assets_version=1"></script>',
 			),
 			array(
 				array('TEST' => 2),
-				'<script type="text/javascript" src="' . $this->phpbb_filesystem->get_web_root_path() . 'tests/template/templates/parent_and_child.js?assets_version=0"></script>',
+				'<script type="text/javascript" src="' . $this->phpbb_path_helper->get_web_root_path() . 'tests/template/templates/parent_and_child.js?assets_version=0"></script>',
 			),
 			array(
 				array('TEST' => 3),
-				'<script type="text/javascript" src="' . $this->phpbb_filesystem->get_web_root_path() . 'tests/template/templates/parent_and_child.js?test=1&assets_version=0"></script>',
+				'<script type="text/javascript" src="' . $this->phpbb_path_helper->get_web_root_path() . 'tests/template/templates/parent_and_child.js?test=1&assets_version=0"></script>',
 			),
 			array(
 				array('TEST' => 4),
-				'<script type="text/javascript" src="' . $this->phpbb_filesystem->get_web_root_path() . 'tests/template/templates/parent_and_child.js?test=1&amp;assets_version=0"></script>',
+				'<script type="text/javascript" src="' . $this->phpbb_path_helper->get_web_root_path() . 'tests/template/templates/parent_and_child.js?test=1&amp;assets_version=0"></script>',
 			),
 			array(
 				array('TEST' => 6),
-				'<script type="text/javascript" src="' . $this->phpbb_filesystem->get_web_root_path() . 'tests/template/parent_templates/parent_only.js?assets_version=1"></script>',
+				'<script type="text/javascript" src="' . $this->phpbb_path_helper->get_web_root_path() . 'tests/template/parent_templates/parent_only.js?assets_version=1"></script>',
 			),
 			array(
 				array('TEST' => 7),
-				'<script type="text/javascript" src="' . $this->phpbb_filesystem->get_web_root_path() . 'tests/template/templates/child_only.js?assets_version=1"></script>',
+				'<script type="text/javascript" src="' . $this->phpbb_path_helper->get_web_root_path() . 'tests/template/templates/child_only.js?assets_version=1"></script>',
 			),
 			array(
 				array('TEST' => 8),
-				'<script type="text/javascript" src="' . $this->phpbb_filesystem->get_web_root_path() . 'tests/template/templates/subdir/parent_only.js?assets_version=1"></script>',
+				'<script type="text/javascript" src="' . $this->phpbb_path_helper->get_web_root_path() . 'tests/template/templates/subdir/parent_only.js?assets_version=1"></script>',
 			),
 			array(
 				array('TEST' => 9),
-				'<script type="text/javascript" src="' . $this->phpbb_filesystem->get_web_root_path() . 'tests/template/templates/subdir/subsubdir/parent_only.js?assets_version=1"></script>',
+				'<script type="text/javascript" src="' . $this->phpbb_path_helper->get_web_root_path() . 'tests/template/templates/subdir/subsubdir/parent_only.js?assets_version=1"></script>',
 			),
 			array(
 				array('TEST' => 10),
-				'<script type="text/javascript" src="' . $this->phpbb_filesystem->get_web_root_path() . 'tests/template/templates/subdir/parent_only.js?assets_version=1"></script>',
+				'<script type="text/javascript" src="' . $this->phpbb_path_helper->get_web_root_path() . 'tests/template/templates/subdir/parent_only.js?assets_version=1"></script>',
 			),
 			array(
 				array('TEST' => 11),
-				'<script type="text/javascript" src="' . $this->phpbb_filesystem->get_web_root_path() . 'tests/template/templates/child_only.js?test1=1&amp;test2=2&amp;assets_version=1#test3"></script>',
+				'<script type="text/javascript" src="' . $this->phpbb_path_helper->get_web_root_path() . 'tests/template/templates/child_only.js?test1=1&amp;test2=2&amp;assets_version=1#test3"></script>',
 			),
 			array(
 				array('TEST' => 12),
-				'<script type="text/javascript" src="' . $this->phpbb_filesystem->get_web_root_path() . 'tests/template/parent_templates/parent_only.js?test1=1&amp;test2=2&amp;assets_version=1#test3"></script>',
+				'<script type="text/javascript" src="' . $this->phpbb_path_helper->get_web_root_path() . 'tests/template/parent_templates/parent_only.js?test1=1&amp;test2=2&amp;assets_version=1#test3"></script>',
 			),
 			array(
 				array('TEST' => 14),
-				'<script type="text/javascript" src="' . $this->phpbb_filesystem->get_web_root_path() . 'tests/template/parent_templates/parent_only.js?test1=&quot;&amp;assets_version=1#test3"></script>',
+				'<script type="text/javascript" src="' . $this->phpbb_path_helper->get_web_root_path() . 'tests/template/parent_templates/parent_only.js?test1=&quot;&amp;assets_version=1#test3"></script>',
 			),
 			array(
 				array('TEST' => 15),
@@ -84,7 +84,7 @@ class phpbb_template_template_includejs_test extends phpbb_template_template_tes
 			),
 			array(
 				array('TEST' => 18),
-				'<script type="text/javascript" src="' . $this->phpbb_filesystem->get_web_root_path() . 'tests/template/templates/parent_and_child.js?test=1&test2=0&amp;assets_version=1"></script>',
+				'<script type="text/javascript" src="' . $this->phpbb_path_helper->get_web_root_path() . 'tests/template/templates/parent_and_child.js?test=1&test2=0&amp;assets_version=1"></script>',
 			),
 		);
 	}
diff --git a/tests/template/template_test_case.php b/tests/template/template_test_case.php
index e9cbdec1d9..c75b1e5065 100644
--- a/tests/template/template_test_case.php
+++ b/tests/template/template_test_case.php
@@ -63,16 +63,17 @@ class phpbb_template_template_test_case extends phpbb_test_case
 		$config = new \phpbb\config\config(array_merge($defaults, $new_config));
 		$this->user = new \phpbb\user;
 
-		$phpbb_filesystem = new \phpbb\filesystem(
+		$path_helper = new \phpbb\path_helper(
 			new \phpbb\symfony_request(
 				new phpbb_mock_request()
 			),
+			new \phpbb\filesystem(),
 			$phpbb_root_path,
 			$phpEx
 		);
 
 		$this->template_path = $this->test_path . '/templates';
-		$this->template = new \phpbb\template\twig\twig($phpbb_filesystem, $config, $this->user, new \phpbb\template\context());
+		$this->template = new \phpbb\template\twig\twig($path_helper, $config, $this->user, new \phpbb\template\context());
 		$this->template->set_custom_style('tests', $this->template_path);
 	}
 
diff --git a/tests/template/template_test_case_with_tree.php b/tests/template/template_test_case_with_tree.php
index 232331d37c..e614c42d73 100644
--- a/tests/template/template_test_case_with_tree.php
+++ b/tests/template/template_test_case_with_tree.php
@@ -18,17 +18,18 @@ class phpbb_template_template_test_case_with_tree extends phpbb_template_templat
 		$defaults = $this->config_defaults();
 		$config = new \phpbb\config\config(array_merge($defaults, $new_config));
 
-		$this->phpbb_filesystem = new \phpbb\filesystem(
+		$this->phpbb_path_helper = new \phpbb\path_helper(
 			new \phpbb\symfony_request(
 				new phpbb_mock_request()
 			),
+			new \phpbb\filesystem(),
 			$phpbb_root_path,
 			$phpEx
 		);
 
 		$this->template_path = $this->test_path . '/templates';
 		$this->parent_template_path = $this->test_path . '/parent_templates';
-		$this->template = new phpbb\template\twig\twig($this->phpbb_filesystem, $config, $user, new phpbb\template\context());
+		$this->template = new phpbb\template\twig\twig($this->phpbb_path_helper, $config, $user, new phpbb\template\context());
 		$this->template->set_custom_style('tests', array($this->template_path, $this->parent_template_path));
 	}
 }
diff --git a/tests/test_framework/phpbb_functional_test_case.php b/tests/test_framework/phpbb_functional_test_case.php
index e078b09082..f5e2e2c77d 100644
--- a/tests/test_framework/phpbb_functional_test_case.php
+++ b/tests/test_framework/phpbb_functional_test_case.php
@@ -203,13 +203,7 @@ class phpbb_functional_test_case extends phpbb_test_case
 			$container,
 			$db,
 			$config,
-			new phpbb\filesystem(
-				new phpbb\symfony_request(
-					new phpbb_mock_request()
-				),
-				$phpbb_root_path,
-				$php_ext
-			),
+			new phpbb\filesystem(),
 			self::$config['table_prefix'] . 'ext',
 			dirname(__FILE__) . '/',
 			$php_ext,