16 files changed, 645 insertions, 207 deletions
diff --git a/phpBB/phpbb/template/asset.php b/phpBB/phpbb/template/asset.php
index ff9366af4a..cb00f16549 100644
--- a/phpBB/phpbb/template/asset.php
+++ b/phpBB/phpbb/template/asset.php
@@ -20,15 +20,20 @@ class asset
 	/** @var \phpbb\path_helper **/
 	protected $path_helper;
 
+	/** @var \phpbb\filesystem\filesystem */
+	protected $filesystem;
+
 	/**
 	* Constructor
 	*
 	* @param string $url URL
 	* @param \phpbb\path_helper $path_helper Path helper object
+	* @param \phpbb\filesystem\filesystem $filesystem
 	*/
-	public function __construct($url, \phpbb\path_helper $path_helper)
+	public function __construct($url, \phpbb\path_helper $path_helper, \phpbb\filesystem\filesystem $filesystem)
 	{
 		$this->path_helper = $path_helper;
+		$this->filesystem = $filesystem;
 
 		$this->set_url($url);
 	}
@@ -152,18 +157,18 @@ class asset
 	*/
 	public function set_path($path, $urlencode = false)
 	{
-		// Since 1.7.0 Twig returns the real path of the file. We need it to be relative to the working directory.
-		$real_root_path = realpath($this->path_helper->get_phpbb_root_path()) . DIRECTORY_SEPARATOR;
+		// Since 1.7.0 Twig returns the real path of the file. We need it to be relative.
+		$real_root_path = $this->filesystem->realpath($this->path_helper->get_phpbb_root_path()) . DIRECTORY_SEPARATOR;
 
 		// If the asset is under the phpBB root path we need to remove its path and then prepend $phpbb_root_path
-		if (substr($path . DIRECTORY_SEPARATOR, 0, strlen($real_root_path)) === $real_root_path)
+		if ($real_root_path && substr($path . DIRECTORY_SEPARATOR, 0, strlen($real_root_path)) === $real_root_path)
 		{
 			$path = $this->path_helper->get_phpbb_root_path() . str_replace('\\', '/', substr($path, strlen($real_root_path)));
 		}
 		else
 		{
 			// Else we make the path relative to the current working directory
-			$real_root_path = realpath('.') . DIRECTORY_SEPARATOR;
+			$real_root_path = $this->filesystem->realpath('.') . DIRECTORY_SEPARATOR;
 			if ($real_root_path && substr($path . DIRECTORY_SEPARATOR, 0, strlen($real_root_path)) === $real_root_path)
 			{
 				$path = str_replace('\\', '/', substr($path, strlen($real_root_path)));
diff --git a/phpBB/phpbb/template/assets_bag.php b/phpBB/phpbb/template/assets_bag.php
new file mode 100644
index 0000000000..067b0eb8f1
--- /dev/null
+++ b/phpBB/phpbb/template/assets_bag.php
@@ -0,0 +1,95 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\template;
+
+class assets_bag
+{
+	/** @var asset[] */
+	protected $stylesheets = [];
+
+	/** @var asset[] */
+	protected $scripts = [];
+
+	/**
+	 * Add a css asset to the bag
+	 *
+	 * @param asset $asset
+	 */
+	public function add_stylesheet(asset $asset)
+	{
+		$this->stylesheets[] = $asset;
+	}
+
+	/**
+	 * Add a js script asset to the bag
+	 *
+	 * @param asset $asset
+	 */
+	public function add_script(asset $asset)
+	{
+		$this->scripts[] = $asset;
+	}
+
+	/**
+	 * Returns all css assets
+	 *
+	 * @return asset[]
+	 */
+	public function get_stylesheets()
+	{
+		return $this->stylesheets;
+	}
+
+	/**
+	 * Returns all js assets
+	 *
+	 * @return asset[]
+	 */
+	public function get_scripts()
+	{
+		return $this->scripts;
+	}
+
+	/**
+	 * Returns the HTML code to includes all css assets
+	 *
+	 * @return string
+	 */
+	public function get_stylesheets_content()
+	{
+		$output = '';
+		foreach ($this->stylesheets as $stylesheet)
+		{
+			$output .= "<link href=\"{$stylesheet->get_url()}\" rel=\"stylesheet\" media=\"screen\" />\n";
+		}
+
+		return $output;
+	}
+
+	/**
+	 * Returns the HTML code to includes all js assets
+	 *
+	 * @return string
+	 */
+	public function get_scripts_content()
+	{
+		$output = '';
+		foreach ($this->scripts as $script)
+		{
+			$output .= "<script src=\"{$script->get_url()}\"></script>\n";
+		}
+
+		return $output;
+	}
+}
diff --git a/phpBB/phpbb/template/base.php b/phpBB/phpbb/template/base.php
index 41c0a01ba8..d502aceab8 100644
--- a/phpBB/phpbb/template/base.php
+++ b/phpBB/phpbb/template/base.php
@@ -107,6 +107,27 @@ abstract class base implements template
 	/**
 	* {@inheritdoc}
 	*/
+	public function retrieve_vars(array $vararray)
+	{
+		$result = array();
+		foreach ($vararray as $varname)
+		{
+			$result[$varname] = $this->retrieve_var($varname);
+		}
+		return $result;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function retrieve_var($varname)
+	{
+		return $this->context->retrieve_var($varname);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
 	public function assign_block_vars($blockname, array $vararray)
 	{
 		$this->context->assign_block_vars($blockname, $vararray);
@@ -127,6 +148,14 @@ abstract class base implements template
 	/**
 	* {@inheritdoc}
 	*/
+	public function retrieve_block_vars($blockname, array $vararray)
+	{
+		return $this->context->retrieve_block_vars($blockname, $vararray);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
 	public function alter_block_array($blockname, array $vararray, $key = false, $mode = 'insert')
 	{
 		return $this->context->alter_block_array($blockname, $vararray, $key, $mode);
diff --git a/phpBB/phpbb/template/context.php b/phpBB/phpbb/template/context.php
index 5d04a09865..202e29ce00 100644
--- a/phpBB/phpbb/template/context.php
+++ b/phpBB/phpbb/template/context.php
@@ -87,6 +87,17 @@ class context
 	}
 
 	/**
+	* Retreive a single scalar value from a single key.
+	*
+	* @param string $varname Variable name
+	* @return mixed Variable value, or null if not set
+	*/
+	public function retrieve_var($varname)
+	{
+		return isset($this->rootref[$varname]) ? $this->rootref[$varname] : null;
+	}
+
+	/**
 	* Returns a reference to template data array.
 	*
 	* This function is public so that template renderer may invoke it.
@@ -131,7 +142,7 @@ class context
 	*/
 	protected function set_num_rows(&$loop_data)
 	{
-		$s_num_rows = sizeof($loop_data);
+		$s_num_rows = count($loop_data);
 		foreach ($loop_data as &$mod_block)
 		{
 			foreach ($mod_block as $sub_block_name => &$sub_block)
@@ -179,70 +190,51 @@ class context
 	public function assign_block_vars($blockname, array $vararray)
 	{
 		$this->num_rows_is_set = false;
-		if (strpos($blockname, '.') !== false)
-		{
-			// Nested block.
-			$blocks = explode('.', $blockname);
-			$blockcount = sizeof($blocks) - 1;
-
-			$str = &$this->tpldata;
-			for ($i = 0; $i < $blockcount; $i++)
-			{
-				$str = &$str[$blocks[$i]];
-				$str = &$str[sizeof($str) - 1];
-			}
 
-			$s_row_count = isset($str[$blocks[$blockcount]]) ? sizeof($str[$blocks[$blockcount]]) : 0;
-			$vararray['S_ROW_COUNT'] = $vararray['S_ROW_NUM'] = $s_row_count;
+		// For nested block, $blockcount > 0, for top-level block, $blockcount == 0
+		$blocks = explode('.', $blockname);
+		$blockcount = count($blocks) - 1;
 
-			// Assign S_FIRST_ROW
-			if (!$s_row_count)
-			{
-				$vararray['S_FIRST_ROW'] = true;
-			}
+		$block = &$this->tpldata;
+		for ($i = 0; $i < $blockcount; $i++)
+		{
+			$pos = strpos($blocks[$i], '[');
+			$name = ($pos !== false) ? substr($blocks[$i], 0, $pos) : $blocks[$i];
+			$block = &$block[$name];
+			$block_count = empty($block) ? 0 : count($block) - 1;
+			$index = (!$pos || strpos($blocks[$i], '[]') === $pos) ? $block_count : (min((int) substr($blocks[$i], $pos + 1, -1), $block_count));
+			$block = &$block[$index];
+		}
 
-			// Assign S_BLOCK_NAME
-			$vararray['S_BLOCK_NAME'] = $blocks[$blockcount];
+		// $block = &$block[$blocks[$i]]; // Do not traverse the last block as it might be empty
+		$name = $blocks[$i];
 
-			// Now the tricky part, we always assign S_LAST_ROW and remove the entry before
-			// This is much more clever than going through the complete template data on display (phew)
-			$vararray['S_LAST_ROW'] = true;
-			if ($s_row_count > 0)
-			{
-				unset($str[$blocks[$blockcount]][($s_row_count - 1)]['S_LAST_ROW']);
-			}
+		// Assign S_ROW_COUNT and S_ROW_NUM
+		$s_row_count = isset($block[$name]) ? count($block[$name]) : 0;
+		$vararray['S_ROW_COUNT'] = $vararray['S_ROW_NUM'] = $s_row_count;
 
-			// Now we add the block that we're actually assigning to.
-			// We're adding a new iteration to this block with the given
-			// variable assignments.
-			$str[$blocks[$blockcount]][] = $vararray;
-		}
-		else
+		// Assign S_FIRST_ROW
+		if (!$s_row_count)
 		{
-			// Top-level block.
-			$s_row_count = (isset($this->tpldata[$blockname])) ? sizeof($this->tpldata[$blockname]) : 0;
-			$vararray['S_ROW_COUNT'] = $vararray['S_ROW_NUM'] = $s_row_count;
-
-			// Assign S_FIRST_ROW
-			if (!$s_row_count)
-			{
-				$vararray['S_FIRST_ROW'] = true;
-			}
+			$vararray['S_FIRST_ROW'] = true;
+		}
 
-			// Assign S_BLOCK_NAME
-			$vararray['S_BLOCK_NAME'] = $blockname;
+		// Assign S_BLOCK_NAME
+		$vararray['S_BLOCK_NAME'] = $name;
 
-			// We always assign S_LAST_ROW and remove the entry before
-			$vararray['S_LAST_ROW'] = true;
-			if ($s_row_count > 0)
-			{
-				unset($this->tpldata[$blockname][($s_row_count - 1)]['S_LAST_ROW']);
-			}
-
-			// Add a new iteration to this block with the variable assignments we were given.
-			$this->tpldata[$blockname][] = $vararray;
+		// Now the tricky part, we always assign S_LAST_ROW and remove the entry before
+		// This is much more clever than going through the complete template data on display (phew)
+		$vararray['S_LAST_ROW'] = true;
+		if ($s_row_count > 0)
+		{
+			unset($block[$name][($s_row_count - 1)]['S_LAST_ROW']);
 		}
 
+		// Now we add the block that we're actually assigning to.
+		// We're adding a new iteration to this block with the given
+		// variable assignments.
+		$block[$name][] = $vararray;
+
 		return true;
 	}
 
@@ -264,57 +256,116 @@ class context
 	}
 
 	/**
-	* Find the index for a specified key in the innermost specified block
-	*
-	* @param	string	$blockname	the blockname, for example 'loop'
-	* @param	mixed	$key		Key to search for
-	*
-	* array: KEY => VALUE [the key/value pair to search for within the loop to determine the correct position]
-	*
-	* int: Position [the position to search for]
+	* Retrieve key variable pairs from the specified block
 	*
-	* If key is false the position is set to 0
-	* If key is true the position is set to the last entry
-	*
-	* @return mixed false if not found, index position otherwise; be sure to test with ===
+	* @param string $blockname Name of block to retrieve $vararray from
+	* @param array $vararray An array of variable names, empty array retrieves all vars
+	* @return array of hashes with variable name as key and retrieved value or null as value
 	*/
-	public function find_key_index($blockname, $key)
+	public function retrieve_block_vars($blockname, array $vararray)
 	{
 		// For nested block, $blockcount > 0, for top-level block, $blockcount == 0
 		$blocks = explode('.', $blockname);
-		$blockcount = sizeof($blocks) - 1;
+		$blockcount = count($blocks) - 1;
 
 		$block = $this->tpldata;
-		for ($i = 0; $i < $blockcount; $i++)
+		for ($i = 0; $i <= $blockcount; $i++)
 		{
 			if (($pos = strpos($blocks[$i], '[')) !== false)
 			{
 				$name = substr($blocks[$i], 0, $pos);
 
+				if (empty($block[$name]))
+				{
+					return array();
+				}
+
 				if (strpos($blocks[$i], '[]') === $pos)
 				{
-					$index = sizeof($block[$name]) - 1;
+					$index = count($block[$name]) - 1;
 				}
 				else
 				{
-					$index = min((int) substr($blocks[$i], $pos + 1, -1), sizeof($block[$name]) - 1);
+					$index = min((int) substr($blocks[$i], $pos + 1, -1), count($block[$name]) - 1);
 				}
 			}
 			else
 			{
 				$name = $blocks[$i];
-				$index = sizeof($block[$name]) - 1;
+				if (empty($block[$name]))
+				{
+					return array();
+				}
+
+				$index = count($block[$name]) - 1;
 			}
+			$block = $block[$name];
+			$block = $block[$index];
+		}
+
+		$result = array();
+		if ($vararray === array())
+		{
+			// The calculated vars that depend on the block position are excluded from the complete block returned results
+			$excluded_vars = array('S_FIRST_ROW', 'S_LAST_ROW', 'S_BLOCK_NAME', 'S_NUM_ROWS', 'S_ROW_COUNT', 'S_ROW_NUM');
+
+			foreach ($block as $varname => $varvalue)
+			{
+				if ($varname === strtoupper($varname) && !is_array($varvalue) && !in_array($varname, $excluded_vars))
+				{
+					$result[$varname] = $varvalue;
+				}
+			}
+		}
+		else
+		{
+			foreach ($vararray as $varname)
+			{
+				$result[$varname] = isset($block[$varname]) ? $block[$varname] : null;
+			}
+		}
+		return $result;
+	}
+
+	/**
+	* Find the index for a specified key in the innermost specified block
+	*
+	* @param	string	$blockname	the blockname, for example 'loop'
+	* @param	mixed	$key		Key to search for
+	*
+	* array: KEY => VALUE [the key/value pair to search for within the loop to determine the correct position]
+	*
+	* int: Position [the position to search for]
+	*
+	* If key is false the position is set to 0
+	* If key is true the position is set to the last entry
+	*
+	* @return mixed false if not found, index position otherwise; be sure to test with ===
+	*/
+	public function find_key_index($blockname, $key)
+	{
+		// For nested block, $blockcount > 0, for top-level block, $blockcount == 0
+		$blocks = explode('.', $blockname);
+		$blockcount = count($blocks) - 1;
+
+		$block = $this->tpldata;
+		for ($i = 0; $i < $blockcount; $i++)
+		{
+			$pos = strpos($blocks[$i], '[');
+			$name = ($pos !== false) ? substr($blocks[$i], 0, $pos) : $blocks[$i];
+
 			if (!isset($block[$name]))
 			{
 				return false;
 			}
-			$block = $block[$name];
-			if (!isset($block[$index]))
+
+			$index = (!$pos || strpos($blocks[$i], '[]') === $pos) ? (count($block[$name]) - 1) : (min((int) substr($blocks[$i], $pos + 1, -1), count($block[$name]) - 1));
+
+			if (!isset($block[$name][$index]))
 			{
 				return false;
 			}
-			$block = $block[$index];
+			$block = $block[$name][$index];
 		}
 
 		if (!isset($block[$blocks[$i]]))
@@ -324,9 +375,9 @@ class context
 		$block = $block[$blocks[$i]]; // Traverse the last block
 
 		// Change key to zero (change first position) if false and to last position if true
-		if ($key === false || $key === true)
+		if (is_bool($key))
 		{
-			return ($key === false) ? 0 : sizeof($block) - 1;
+			return (!$key) ? 0 : count($block) - 1;
 		}
 
 		// Get correct position if array given
@@ -343,7 +394,7 @@ class context
 			}
 		}
 
-		return (is_int($key) && ((0 <= $key) && ($key < sizeof($block)))) ? $key : false;
+		return (is_int($key) && ((0 <= $key) && ($key < count($block)))) ? $key : false;
 	}
 
 	/**
@@ -363,10 +414,11 @@ class context
 	* If key is false the position is set to 0
 	* If key is true the position is set to the last entry
 	*
-	* @param	string	$mode		Mode to execute (valid modes are 'insert' and 'change')
+	* @param	string	$mode		Mode to execute (valid modes are 'insert', 'change' and 'delete')
 	*
 	*	If insert, the vararray is inserted at the given position (position counting from zero).
 	*	If change, the current block gets merged with the vararray (resulting in new key/value pairs be added and existing keys be replaced by the new \value).
+	*	If delete, the vararray is ignored, and the block at the given position (counting from zero) is removed.
 	*
 	* Since counting begins by zero, inserting at the last position will result in this array: array(vararray, last positioned array)
 	* and inserting at position 1 will result in this array: array(first positioned array, vararray, following vars)
@@ -379,7 +431,7 @@ class context
 
 		// For nested block, $blockcount > 0, for top-level block, $blockcount == 0
 		$blocks = explode('.', $blockname);
-		$blockcount = sizeof($blocks) - 1;
+		$blockcount = count($blocks) - 1;
 
 		$block = &$this->tpldata;
 		for ($i = 0; $i < $blockcount; $i++)
@@ -390,17 +442,17 @@ class context
 
 				if (strpos($blocks[$i], '[]') === $pos)
 				{
-					$index = sizeof($block[$name]) - 1;
+					$index = count($block[$name]) - 1;
 				}
 				else
 				{
-					$index = min((int) substr($blocks[$i], $pos + 1, -1), sizeof($block[$name]) - 1);
+					$index = min((int) substr($blocks[$i], $pos + 1, -1), count($block[$name]) - 1);
 				}
 			}
 			else
 			{
 				$name = $blocks[$i];
-				$index = sizeof($block[$name]) - 1;
+				$index = count($block[$name]) - 1;
 			}
 			$block = &$block[$name];
 			$block = &$block[$index];
@@ -422,7 +474,7 @@ class context
 		// Change key to zero (change first position) if false and to last position if true
 		if ($key === false || $key === true)
 		{
-			$key = ($key === false) ? 0 : sizeof($block);
+			$key = ($key === false) ? 0 : count($block);
 		}
 
 		// Get correct position if array given
@@ -452,9 +504,9 @@ class context
 		if ($mode == 'insert')
 		{
 			// Make sure we are not exceeding the last iteration
-			if ($key >= sizeof($block))
+			if ($key >= count($block))
 			{
-				$key = sizeof($block);
+				$key = count($block);
 				unset($block[($key - 1)]['S_LAST_ROW']);
 				$vararray['S_LAST_ROW'] = true;
 			}
@@ -469,7 +521,7 @@ class context
 			$vararray['S_BLOCK_NAME'] = $name;
 
 			// Re-position template blocks
-			for ($i = sizeof($block); $i > $key; $i--)
+			for ($i = count($block); $i > $key; $i--)
 			{
 				$block[$i] = $block[$i-1];
 
@@ -487,12 +539,12 @@ class context
 		if ($mode == 'change')
 		{
 			// If key is out of bounds, do not change anything
-			if ($key > sizeof($block) || $key < 0)
+			if ($key > count($block) || $key < 0)
 			{
 				return false;
 			}
 
-			if ($key == sizeof($block))
+			if ($key == count($block))
 			{
 				$key--;
 			}
@@ -502,6 +554,45 @@ class context
 			return true;
 		}
 
+		// Delete Block
+		if ($mode == 'delete')
+		{
+			// If we are exceeding last iteration, do not delete anything
+			if ($key > count($block) || $key < 0)
+			{
+				return false;
+			}
+
+			// If we are positioned at the end, we remove the last element
+			if ($key == count($block))
+			{
+				$key--;
+			}
+
+			// We are deleting the last element in the block, so remove the block
+			if (count($block) === 1)
+			{
+				$block = null; // unset($block); does not work on references
+				return true;
+			}
+
+			// Re-position template blocks
+			for ($i = $key; $i < count($block)-1; $i++)
+			{
+				$block[$i] = $block[$i+1];
+				$block[$i]['S_ROW_COUNT'] = $block[$i]['S_ROW_NUM'] = $i;
+			}
+
+			// Remove the last element
+			unset($block[$i]);
+
+			// Set first and last elements again, in case they were removed
+			$block[0]['S_FIRST_ROW'] = true;
+			$block[count($block)-1]['S_LAST_ROW'] = true;
+
+			return true;
+		}
+
 		return false;
 	}
 
@@ -518,13 +609,13 @@ class context
 		{
 			// Nested block.
 			$blocks = explode('.', $blockname);
-			$blockcount = sizeof($blocks) - 1;
+			$blockcount = count($blocks) - 1;
 
 			$str = &$this->tpldata;
 			for ($i = 0; $i < $blockcount; $i++)
 			{
 				$str = &$str[$blocks[$i]];
-				$str = &$str[sizeof($str) - 1];
+				$str = &$str[count($str) - 1];
 			}
 
 			unset($str[$blocks[$blockcount]]);
diff --git a/phpBB/phpbb/template/exception/user_object_not_available.php b/phpBB/phpbb/template/exception/user_object_not_available.php
new file mode 100644
index 0000000000..62fd2743c1
--- /dev/null
+++ b/phpBB/phpbb/template/exception/user_object_not_available.php
@@ -0,0 +1,22 @@
+<?php
+/**
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
+
+namespace phpbb\template\exception;
+
+/**
+ * This exception is thrown when the user object was not set but it is required by the called method
+ */
+class user_object_not_available extends \phpbb\exception\runtime_exception
+{
+
+}
diff --git a/phpBB/phpbb/template/template.php b/phpBB/phpbb/template/template.php
index 9e3d658ca8..df83d5bc43 100644
--- a/phpBB/phpbb/template/template.php
+++ b/phpBB/phpbb/template/template.php
@@ -128,6 +128,22 @@ interface template
 	public function append_var($varname, $varval);
 
 	/**
+	* Retrieve multiple template values
+	*
+	* @param array $vararray An array with variable names
+	* @return array A hash of variable name => value pairs (value is null if not set)
+	*/
+	public function retrieve_vars(array $vararray);
+
+	/**
+	* Retreive a single scalar value from a single key.
+	*
+	* @param string $varname Variable name
+	* @return mixed Variable value, or null if not set
+	*/
+	public function retrieve_var($varname);
+
+	/**
 	* Assign key variable pairs from an array to a specified block
 	* @param string $blockname Name of block to assign $vararray to
 	* @param array $vararray A hash of variable name => value pairs
@@ -144,6 +160,14 @@ interface template
 	public function assign_block_vars_array($blockname, array $block_vars_array);
 
 	/**
+	* Retrieve variable values from an specified block
+	* @param string $blockname Name of block to retrieve $vararray from
+	* @param array $vararray An array with variable names, empty array gets all vars
+	* @return array A hash of variable name => value pairs (value is null if not set)
+	*/
+	public function retrieve_block_vars($blockname, array $vararray);
+
+	/**
 	* Change already assigned key variable pair (one-dimensional - single loop entry)
 	*
 	* An example of how to use this function:
@@ -160,10 +184,11 @@ interface template
 	* If key is false the position is set to 0
 	* If key is true the position is set to the last entry
 	*
-	* @param	string	$mode		Mode to execute (valid modes are 'insert' and 'change')
+	* @param	string	$mode		Mode to execute (valid modes are 'insert', 'change' and 'delete')
 	*
 	*	If insert, the vararray is inserted at the given position (position counting from zero).
 	*	If change, the current block gets merged with the vararray (resulting in new \key/value pairs be added and existing keys be replaced by the new \value).
+	*	If delete, the vararray is ignored, and the block at the given position (counting from zero) is removed.
 	*
 	* Since counting begins by zero, inserting at the last position will result in this array: array(vararray, last positioned array)
 	* and inserting at position 1 will result in this array: array(first positioned array, vararray, following vars)
diff --git a/phpBB/phpbb/template/twig/environment.php b/phpBB/phpbb/template/twig/environment.php
index 476ffd935e..ac4b16e457 100644
--- a/phpBB/phpbb/template/twig/environment.php
+++ b/phpBB/phpbb/template/twig/environment.php
@@ -13,17 +13,28 @@
 
 namespace phpbb\template\twig;
 
+use phpbb\template\assets_bag;
+
 class environment extends \Twig_Environment
 {
 	/** @var \phpbb\config\config */
 	protected $phpbb_config;
 
+	/** @var \phpbb\filesystem\filesystem */
+	protected $filesystem;
+
 	/** @var \phpbb\path_helper */
 	protected $phpbb_path_helper;
 
+	/** @var \Symfony\Component\DependencyInjection\ContainerInterface */
+	protected $container;
+
 	/** @var \phpbb\extension\manager */
 	protected $extension_manager;
 
+	/** @var \phpbb\event\dispatcher_interface */
+	protected $phpbb_dispatcher;
+
 	/** @var string */
 	protected $phpbb_root_path;
 
@@ -33,26 +44,43 @@ class environment extends \Twig_Environment
 	/** @var array **/
 	protected $namespace_look_up_order = array('__main__');
 
+	/** @var assets_bag */
+	protected $assets_bag;
+
 	/**
 	* Constructor
 	*
 	* @param \phpbb\config\config $phpbb_config The phpBB configuration
+	* @param \phpbb\filesystem\filesystem $filesystem
 	* @param \phpbb\path_helper $path_helper phpBB path helper
+	* @param string $cache_path The path to the cache directory
 	* @param \phpbb\extension\manager $extension_manager phpBB extension manager
 	* @param \Twig_LoaderInterface $loader Twig loader interface
+	* @param \phpbb\event\dispatcher_interface	$phpbb_dispatcher	Event dispatcher object
 	* @param array $options Array of options to pass to Twig
 	*/
-	public function __construct($phpbb_config, \phpbb\path_helper $path_helper, \phpbb\extension\manager $extension_manager = null, \Twig_LoaderInterface $loader = null, $options = array())
+	public function __construct(\phpbb\config\config $phpbb_config, \phpbb\filesystem\filesystem $filesystem, \phpbb\path_helper $path_helper, $cache_path, \phpbb\extension\manager $extension_manager = null, \Twig_LoaderInterface $loader = null, \phpbb\event\dispatcher_interface $phpbb_dispatcher = null, $options = array())
 	{
 		$this->phpbb_config = $phpbb_config;
 
+		$this->filesystem = $filesystem;
 		$this->phpbb_path_helper = $path_helper;
 		$this->extension_manager = $extension_manager;
+		$this->phpbb_dispatcher = $phpbb_dispatcher;
 
 		$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);
+		$this->assets_bag = new assets_bag();
+
+		$options = array_merge(array(
+			'cache'			=> (defined('IN_INSTALL')) ? false : $cache_path,
+			'debug'			=> false,
+			'auto_reload'	=> (bool) $this->phpbb_config['load_tplcompile'],
+			'autoescape'	=> false,
+		), $options);
+
+		parent::__construct($loader, $options);
 	}
 
 	/**
@@ -78,16 +106,26 @@ class environment extends \Twig_Environment
 	}
 
 	/**
-	* Get the phpBB root path
-	*
-	* @return string
-	*/
+	 * Get the phpBB root path
+	 *
+	 * @return string
+	 */
 	public function get_phpbb_root_path()
 	{
 		return $this->phpbb_root_path;
 	}
 
 	/**
+	* Get the filesystem object
+	*
+	* @return \phpbb\filesystem\filesystem
+	*/
+	public function get_filesystem()
+	{
+		return $this->filesystem;
+	}
+
+	/**
 	* Get the web root path
 	*
 	* @return string
@@ -108,6 +146,16 @@ class environment extends \Twig_Environment
 	}
 
 	/**
+	 * Gets the assets bag
+	 *
+	 * @return assets_bag
+	 */
+	public function get_assets_bag()
+	{
+		return $this->assets_bag;
+	}
+
+	/**
 	* Get the namespace look up order
 	*
 	* @return array
@@ -131,6 +179,84 @@ class environment extends \Twig_Environment
 	}
 
 	/**
+	 * {@inheritdoc}
+	 */
+	public function render($name, array $context = [])
+	{
+		return $this->display_with_assets($name, $context);
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	public function display($name, array $context = [])
+	{
+		echo $this->display_with_assets($name, $context);
+	}
+
+	/**
+	 * {@inheritdoc}
+	 */
+	private function display_with_assets($name, array $context = [])
+	{
+		$placeholder_salt = unique_id();
+
+		if (array_key_exists('definition', $context))
+		{
+			$context['definition']->set('SCRIPTS', '__SCRIPTS_' . $placeholder_salt . '__');
+			$context['definition']->set('STYLESHEETS', '__STYLESHEETS_' . $placeholder_salt . '__');
+		}
+
+		/**
+		* Allow changing the template output stream before rendering
+		*
+		* @event core.twig_environment_render_template_before
+		* @var	array	context		Array with template variables
+		* @var	string  name		The template name
+		* @since 3.2.1-RC1
+		*/
+		if ($this->phpbb_dispatcher)
+		{
+			$vars = array('context', 'name');
+			extract($this->phpbb_dispatcher->trigger_event('core.twig_environment_render_template_before', compact($vars)));
+		}
+
+		$output = parent::render($name, $context);
+
+		/**
+		* Allow changing the template output stream after rendering
+		*
+		* @event core.twig_environment_render_template_after
+		* @var	array	context		Array with template variables
+		* @var	string  name		The template name
+		* @var	string	output		Rendered template output stream
+		* @since 3.2.1-RC1
+		*/
+		if ($this->phpbb_dispatcher)
+		{
+			$vars = array('context', 'name', 'output');
+			extract($this->phpbb_dispatcher->trigger_event('core.twig_environment_render_template_after', compact($vars)));
+		}
+
+		return $this->inject_assets($output, $placeholder_salt);
+	}
+
+	/**
+	 * Injects the assets (from INCLUDECSS/JS) in the output.
+	 *
+	 * @param string $output
+	 *
+	 * @return string
+	 */
+	private function inject_assets($output, $placeholder_salt)
+	{
+		$output = str_replace('__STYLESHEETS_' . $placeholder_salt . '__', $this->assets_bag->get_stylesheets_content(), $output);
+		$output = str_replace('__SCRIPTS_' . $placeholder_salt . '__', $this->assets_bag->get_scripts_content(), $output);
+
+		return $output;
+	}
+
+	/**
 	* Loads a template by name.
 	*
 	* @param string  $name  The template name
diff --git a/phpBB/phpbb/template/twig/extension.php b/phpBB/phpbb/template/twig/extension.php
index d5b14129b5..f6f8e03ca2 100644
--- a/phpBB/phpbb/template/twig/extension.php
+++ b/phpBB/phpbb/template/twig/extension.php
@@ -18,20 +18,20 @@ class extension extends \Twig_Extension
 	/** @var \phpbb\template\context */
 	protected $context;
 
-	/** @var \phpbb\user */
-	protected $user;
+	/** @var \phpbb\language\language */
+	protected $language;
 
 	/**
 	* Constructor
 	*
 	* @param \phpbb\template\context $context
-	* @param \phpbb\user $user
+	* @param \phpbb\language\language $language
 	* @return \phpbb\template\twig\extension
 	*/
-	public function __construct(\phpbb\template\context $context, $user)
+	public function __construct(\phpbb\template\context $context, $language)
 	{
 		$this->context = $context;
-		$this->user = $user;
+		$this->language = $language;
 	}
 
 	/**
@@ -71,6 +71,7 @@ class extension extends \Twig_Extension
 	{
 		return array(
 			new \Twig_SimpleFilter('subset', array($this, 'loop_subset'), array('needs_environment' => true)),
+			// @deprecated 3.2.0 Uses twig's JS escape method instead of addslashes
 			new \Twig_SimpleFilter('addslashes', 'addslashes'),
 		);
 	}
@@ -145,7 +146,7 @@ class extension extends \Twig_Extension
 			//  of items to grab (length)
 
 			// Start must always be the actual starting number for this calculation (not negative)
-			$start = ($start < 0) ? sizeof($item) + $start : $start;
+			$start = ($start < 0) ? count($item) + $start : $start;
 			$end = $end - $start;
 		}
 
@@ -171,14 +172,14 @@ class extension extends \Twig_Extension
 
 		$context_vars = $this->context->get_root_ref();
 
-		if (isset($context_vars['L_' . $key]))
+		if (is_string($key) && isset($context_vars['L_' . $key]))
 		{
 			return $context_vars['L_' . $key];
 		}
 
-		// LA_ is transformed into lang(\'$1\')|addslashes, so we should not
+		// LA_ is transformed into lang(\'$1\')|escape('js'), so we should not
 		// need to check for it
 
-		return call_user_func_array(array($this->user, 'lang'), $args);
+		return call_user_func_array(array($this->language, 'lang'), $args);
 	}
 }
diff --git a/phpBB/phpbb/template/twig/extension/routing.php b/phpBB/phpbb/template/twig/extension/routing.php
new file mode 100644
index 0000000000..829ce738eb
--- /dev/null
+++ b/phpBB/phpbb/template/twig/extension/routing.php
@@ -0,0 +1,43 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\template\twig\extension;
+
+use Symfony\Bridge\Twig\Extension\RoutingExtension;
+use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
+
+class routing extends RoutingExtension
+{
+	/** @var \phpbb\controller\helper */
+	protected $helper;
+
+	/**
+	* Constructor
+	*
+	* @param \phpbb\routing\helper $helper
+	*/
+	public function __construct(\phpbb\routing\helper $helper)
+	{
+		$this->helper = $helper;
+	}
+
+	public function getPath($name, $parameters = array(), $relative = false)
+	{
+		return $this->helper->route($name, $parameters, true, false, $relative ? UrlGeneratorInterface::RELATIVE_PATH : UrlGeneratorInterface::ABSOLUTE_PATH);
+	}
+
+	public function getUrl($name, $parameters = array(), $schemeRelative = false)
+	{
+		return $this->helper->route($name, $parameters, true, false, $schemeRelative ? UrlGeneratorInterface::NETWORK_PATH : UrlGeneratorInterface::ABSOLUTE_URL);
+	}
+}
diff --git a/phpBB/phpbb/template/twig/lexer.php b/phpBB/phpbb/template/twig/lexer.php
index c5dc7273ba..d0bcfa615e 100644
--- a/phpBB/phpbb/template/twig/lexer.php
+++ b/phpBB/phpbb/template/twig/lexer.php
@@ -15,8 +15,21 @@ namespace phpbb\template\twig;
 
 class lexer extends \Twig_Lexer
 {
+	public function set_environment(\Twig_Environment $env)
+	{
+		$this->env = $env;
+	}
+
 	public function tokenize($code, $filename = null)
 	{
+		// Handle \Twig_Source format input
+		if ($code instanceof \Twig_Source)
+		{
+			$source = $code;
+			$code = $source->getCode();
+			$filename = $source->getName();
+		}
+
 		// Our phpBB tags
 		// Commented out tokens are handled separately from the main replace
 		$phpbb_tags = array(
@@ -112,15 +125,16 @@ class lexer extends \Twig_Lexer
 		// Appends any filters after lang()
 		$code = preg_replace('#{L_([a-zA-Z0-9_\.]+)(\|[^}]+?)?}#', '{{ lang(\'$1\')$2 }}', $code);
 
-		// Replace all of our escaped language variables, {LA_VARNAME}, with Twig style, {{ lang('NAME')|addslashes }}
-		// Appends any filters after lang(), but before addslashes
-		$code = preg_replace('#{LA_([a-zA-Z0-9_\.]+)(\|[^}]+?)?}#', '{{ lang(\'$1\')$2|addslashes }}', $code);
+		// Replace all of our escaped language variables, {LA_VARNAME}, with Twig style, {{ lang('NAME')|escape('js') }}
+		// Appends any filters after lang(), but before escape('js')
+		$code = preg_replace('#{LA_([a-zA-Z0-9_\.]+)(\|[^}]+?)?}#', '{{ lang(\'$1\')$2|escape(\'js\') }}', $code);
 
 		// Replace all of our variables, {VARNAME}, with Twig style, {{ VARNAME }}
 		// Appends any filters
 		$code = preg_replace('#{([a-zA-Z0-9_\.]+)(\|[^}]+?)?}#', '{{ $1$2 }}', $code);
 
-		return parent::tokenize($code, $filename);
+		// Tokenize \Twig_Source instance
+		return parent::tokenize(new \Twig_Source($code, $filename));
 	}
 
 	/**
diff --git a/phpBB/phpbb/template/twig/loader.php b/phpBB/phpbb/template/twig/loader.php
index 139a413b70..c13e3ee298 100644
--- a/phpBB/phpbb/template/twig/loader.php
+++ b/phpBB/phpbb/template/twig/loader.php
@@ -21,6 +21,24 @@ class loader extends \Twig_Loader_Filesystem
 	protected $safe_directories = array();
 
 	/**
+	 * @var \phpbb\filesystem\filesystem_interface
+	 */
+	protected $filesystem;
+
+	/**
+	 * Constructor
+	 *
+	 * @param \phpbb\filesystem\filesystem_interface $filesystem
+	 * @param string|array	$paths
+	 */
+	public function __construct(\phpbb\filesystem\filesystem_interface $filesystem, $paths = array())
+	{
+		$this->filesystem = $filesystem;
+
+		parent::__construct($paths, $this->filesystem->realpath(dirname(__FILE__)));
+	}
+
+	/**
 	* Set safe directories
 	*
 	* @param array $directories Array of directories that are safe (empty to clear)
@@ -49,7 +67,7 @@ class loader extends \Twig_Loader_Filesystem
 	*/
 	public function addSafeDirectory($directory)
 	{
-		$directory = phpbb_realpath($directory);
+		$directory = $this->filesystem->realpath($directory);
 
 		if ($directory !== false)
 		{
@@ -83,6 +101,16 @@ class loader extends \Twig_Loader_Filesystem
 	}
 
 	/**
+	 * Adds a realpath call to fix a BC break in Twig 1.26 (https://github.com/twigphp/Twig/issues/2145)
+	 *
+	 * {@inheritdoc}
+	 */
+	public function addPath($path, $namespace = self::MAIN_NAMESPACE)
+	{
+		return parent::addPath($this->filesystem->realpath($path), $namespace);
+	}
+
+	/**
 	* Find the template
 	*
 	* Override for Twig_Loader_Filesystem::findTemplate to add support
@@ -119,7 +147,7 @@ class loader extends \Twig_Loader_Filesystem
 				//	can now check if we're within a "safe" directory
 
 				// Find the real path of the directory the file is in
-				$directory = phpbb_realpath(dirname($file));
+				$directory = $this->filesystem->realpath(dirname($file));
 
 				if ($directory === false)
 				{
diff --git a/phpBB/phpbb/template/twig/node/event.php b/phpBB/phpbb/template/twig/node/event.php
index b765bde98d..11fdb75247 100644
--- a/phpBB/phpbb/template/twig/node/event.php
+++ b/phpBB/phpbb/template/twig/node/event.php
@@ -46,7 +46,7 @@ class event extends \Twig_Node
 		{
 			$ext_namespace = str_replace('/', '_', $ext_namespace);
 
-			if (defined('DEBUG'))
+			if ($this->environment->isDebug())
 			{
 				// If debug mode is enabled, lets check for new/removed EVENT
 				//  templates on page load rather than at compile. This is
@@ -58,7 +58,7 @@ class event extends \Twig_Node
 				;
 			}
 
-			if (defined('DEBUG') || $this->environment->getLoader()->exists('@' . $ext_namespace . '/' . $location . '.html'))
+			if ($this->environment->isDebug() || $this->environment->getLoader()->exists('@' . $ext_namespace . '/' . $location . '.html'))
 			{
 				$compiler
 					->write("\$previous_look_up_order = \$this->env->getNamespaceLookUpOrder();\n")
@@ -70,7 +70,7 @@ class event extends \Twig_Node
 				;
 			}
 
-			if (defined('DEBUG'))
+			if ($this->environment->isDebug())
 			{
 				$compiler
 					->outdent()
diff --git a/phpBB/phpbb/template/twig/node/includeasset.php b/phpBB/phpbb/template/twig/node/includeasset.php
index 15195a226b..12034b7820 100644
--- a/phpBB/phpbb/template/twig/node/includeasset.php
+++ b/phpBB/phpbb/template/twig/node/includeasset.php
@@ -39,7 +39,7 @@ abstract class includeasset extends \Twig_Node
 			->write("\$asset_file = ")
 			->subcompile($this->getNode('expr'))
 			->raw(";\n")
-			->write("\$asset = new \phpbb\\template\\asset(\$asset_file, \$this->getEnvironment()->get_path_helper());\n")
+			->write("\$asset = new \phpbb\\template\\asset(\$asset_file, \$this->getEnvironment()->get_path_helper(), \$this->getEnvironment()->get_filesystem());\n")
 			->write("if (substr(\$asset_file, 0, 2) !== './' && \$asset->is_relative()) {\n")
 			->indent()
 				->write("\$asset_path = \$asset->get_path();")
@@ -49,33 +49,23 @@ abstract class includeasset extends \Twig_Node
 					->write("\$local_file = \$this->getEnvironment()->findTemplate(\$asset_path);\n")
 					->write("\$asset->set_path(\$local_file, true);\n")
 				->outdent()
-				->write("\$asset->add_assets_version('{$config['assets_version']}');\n")
-				->write("\$asset_file = \$asset->get_url();\n")
 				->write("}\n")
 			->outdent()
 			->write("}\n")
-			->write("\$context['definition']->append('{$this->get_definition_name()}', '")
-		;
-
-		$this->append_asset($compiler);
-
-		$compiler
-			->raw("\n');\n")
+			->write("\n")
+			->write("if (\$asset->is_relative()) {\n")
+			->indent()
+			->write("\$asset->add_assets_version('{$config['assets_version']}');\n")
+			->outdent()
+			->write("}\n")
+			->write("\$this->getEnvironment()->get_assets_bag()->add_{$this->get_setters_name()}(\$asset);")
 		;
 	}
 
 	/**
-	* Get the definition name
-	*
-	* @return string (e.g. 'SCRIPTS')
-	*/
-	abstract public function get_definition_name();
-
-	/**
-	* Append the output code for the asset
+	* Get the name of the assets bag setter
 	*
-	* @param \Twig_Compiler A Twig_Compiler instance
-	* @return null
+	* @return string (e.g. 'script')
 	*/
-	abstract protected function append_asset(\Twig_Compiler $compiler);
+	abstract public function get_setters_name();
 }
diff --git a/phpBB/phpbb/template/twig/node/includecss.php b/phpBB/phpbb/template/twig/node/includecss.php
index 2dac154036..2e97d4972d 100644
--- a/phpBB/phpbb/template/twig/node/includecss.php
+++ b/phpBB/phpbb/template/twig/node/includecss.php
@@ -18,20 +18,8 @@ class includecss extends \phpbb\template\twig\node\includeasset
 	/**
 	* {@inheritdoc}
 	*/
-	public function get_definition_name()
+	public function get_setters_name()
 	{
-		return 'STYLESHEETS';
-	}
-
-	/**
-	* {@inheritdoc}
-	*/
-	public function append_asset(\Twig_Compiler $compiler)
-	{
-		$compiler
-			->raw("<link href=\"' . ")
-			->raw("\$asset_file . '\"")
-			->raw(' rel="stylesheet" type="text/css" media="screen" />')
-		;
+		return 'stylesheet';
 	}
 }
diff --git a/phpBB/phpbb/template/twig/node/includejs.php b/phpBB/phpbb/template/twig/node/includejs.php
index 0f67f9ff60..505b49757b 100644
--- a/phpBB/phpbb/template/twig/node/includejs.php
+++ b/phpBB/phpbb/template/twig/node/includejs.php
@@ -18,22 +18,8 @@ class includejs extends \phpbb\template\twig\node\includeasset
 	/**
 	* {@inheritdoc}
 	*/
-	public function get_definition_name()
+	public function get_setters_name()
 	{
-		return 'SCRIPTS';
-	}
-
-	/**
-	* {@inheritdoc}
-	*/
-	protected function append_asset(\Twig_Compiler $compiler)
-	{
-		$config = $this->environment->get_phpbb_config();
-
-		$compiler
-			->raw("<script type=\"text/javascript\" src=\"' . ")
-			->raw("\$asset_file")
-			->raw(". '\"></script>\n")
-		;
+		return 'script';
 	}
 }
diff --git a/phpBB/phpbb/template/twig/twig.php b/phpBB/phpbb/template/twig/twig.php
index d1bbb2b55a..f322778eda 100644
--- a/phpBB/phpbb/template/twig/twig.php
+++ b/phpBB/phpbb/template/twig/twig.php
@@ -13,6 +13,8 @@
 
 namespace phpbb\template\twig;
 
+use phpbb\template\exception\user_object_not_available;
+
 /**
 * Twig Template class.
 */
@@ -76,11 +78,14 @@ class twig extends \phpbb\template\base
 	*
 	* @param \phpbb\path_helper $path_helper
 	* @param \phpbb\config\config $config
-	* @param \phpbb\user $user
 	* @param \phpbb\template\context $context template context
+	* @param \phpbb\template\twig\environment $twig_environment
+	* @param string $cache_path
+	* @param \phpbb\user|null $user
+	* @param array|\ArrayAccess $extensions
 	* @param \phpbb\extension\manager $extension_manager extension manager, if null then template events will not be invoked
 	*/
-	public function __construct(\phpbb\path_helper $path_helper, $config, $user, \phpbb\template\context $context, \phpbb\extension\manager $extension_manager = null)
+	public function __construct(\phpbb\path_helper $path_helper, $config, \phpbb\template\context $context, \phpbb\template\twig\environment $twig_environment, $cache_path, \phpbb\user $user = null, $extensions = array(), \phpbb\extension\manager $extension_manager = null)
 	{
 		$this->path_helper = $path_helper;
 		$this->phpbb_root_path = $path_helper->get_phpbb_root_path();
@@ -89,41 +94,14 @@ class twig extends \phpbb\template\base
 		$this->user = $user;
 		$this->context = $context;
 		$this->extension_manager = $extension_manager;
+		$this->cachepath = $cache_path;
+		$this->twig = $twig_environment;
 
-		$this->cachepath = $this->phpbb_root_path . 'cache/twig/';
-
-		// Initiate the loader, __main__ namespace paths will be setup later in set_style_names()
-		$loader = new \phpbb\template\twig\loader('');
-
-		$this->twig = new \phpbb\template\twig\environment(
-			$this->config,
-			$this->path_helper,
-			$this->extension_manager,
-			$loader,
-			array(
-				'cache'			=> (defined('IN_INSTALL')) ? false : $this->cachepath,
-				'debug'			=> defined('DEBUG'),
-				'auto_reload'	=> (bool) $this->config['load_tplcompile'],
-				'autoescape'	=> false,
-			)
-		);
-
-		$this->twig->addExtension(
-			new \phpbb\template\twig\extension(
-				$this->context,
-				$this->user
-			)
-		);
-
-		if (defined('DEBUG'))
+		foreach ($extensions as $extension)
 		{
-			$this->twig->addExtension(new \Twig_Extension_Debug());
+			$this->twig->addExtension($extension);
 		}
 
-		$lexer = new \phpbb\template\twig\lexer($this->twig);
-
-		$this->twig->setLexer($lexer);
-
 		// Add admin namespace
 		if ($this->path_helper->get_adm_relative_path() !== null && is_dir($this->phpbb_root_path . $this->path_helper->get_adm_relative_path() . 'style/'))
 		{
@@ -150,9 +128,16 @@ class twig extends \phpbb\template\base
 	* Get the style tree of the style preferred by the current user
 	*
 	* @return array Style tree, most specific first
+	*
+	* @throws \phpbb\template\exception\user_object_not_available	When user service was not set
 	*/
 	public function get_user_style()
 	{
+		if ($this->user === null)
+		{
+			throw new user_object_not_available();
+		}
+
 		$style_list = array(
 			$this->user->style['style_path'],
 		);
@@ -368,14 +353,24 @@ class twig extends \phpbb\template\base
 			$context_vars['.'][0], // To get normal vars
 			array(
 				'definition'	=> new \phpbb\template\twig\definition(),
-				'user'			=> $this->user,
 				'loops'			=> $context_vars, // To get loops
 			)
 		);
 
+		if ($this->user instanceof \phpbb\user)
+		{
+			$vars['user'] = $this->user;
+		}
+
 		// cleanup
 		unset($vars['loops']['.']);
 
+		// Inject in the main context the value added by assign_block_vars() to be able to use directly the Twig loops.
+		foreach ($vars['loops'] as $key => &$value)
+		{
+			$vars[$key] = $value;
+		}
+
 		return $vars;
 	}