diff --git a/phpBB/phpbb/template/context.php b/phpBB/phpbb/template/context.php
index a45c61dbed..ddf46727e1 100644
--- a/phpBB/phpbb/template/context.php
+++ b/phpBB/phpbb/template/context.php
@@ -274,6 +274,11 @@ class context
 			{
 				$name = substr($blocks[$i], 0, $pos);
 
+				if (empty($block[$name]))
+				{
+					return array();
+				}
+
 				if (strpos($blocks[$i], '[]') === $pos)
 				{
 					$index = count($block[$name]) - 1;
@@ -286,6 +291,11 @@ class context
 			else
 			{
 				$name = $blocks[$i];
+				if (empty($block[$name]))
+				{
+					return array();
+				}
+
 				$index = count($block[$name]) - 1;
 			}
 			$block = $block[$name];
diff --git a/tests/template/context_test.php b/tests/template/context_test.php
new file mode 100644
index 0000000000..52ce6c8fde
--- /dev/null
+++ b/tests/template/context_test.php
@@ -0,0 +1,96 @@
+<?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.
+*
+*/
+
+class context_test extends phpbb_test_case
+{
+	protected $context;
+	protected function setUp()
+	{
+		$this->context = new \phpbb\template\context();
+
+		for ($i = 0; $i < 10; $i++)
+		{
+			$this->context->assign_block_vars('block' . $i, array(
+				'FOO' . $i	=> 'foo' . $i,
+				'BAR' . $i	=> 'bar' . $i,
+			));
+
+			for ($j = 0; $j < 10; $j++)
+			{
+				$this->context->assign_block_vars('block' . $i . '.subblock', array(
+					'SUBFOO'	=> 'subfoo' . $j,
+					'SUBBAR'	=> 'subbar' . $j,
+				));
+				
+				for ($k = 0; $k < 10; $k++)
+				{
+					$this->context->assign_block_vars('block' . $i . '.subblock.subsubblock', array(
+						'SUBSUBFOO'	=> 'subsubfoo' . $k,
+						'SUBSUBBAR'	=> 'subsubbar' . $k,
+					));
+				}
+			}
+		}
+	}
+
+	public function retrieve_block_vars_data()
+	{
+		return array(
+			array('foo', array(), array()), // non-existent top-level block
+			array('block1.foo', array(), array()), // non-existent sub-level block
+			array('block1', array(), array( // top-level block, all vars
+				'FOO1'	=> 'foo1',
+				'BAR1'	=> 'bar1',
+			)),
+			array('block1', array('FOO1'), array( // top-level block, one var
+				'FOO1'	=> 'foo1',
+			)),
+			array('block2.subblock', array(), array( // sub-level block, all vars
+				'SUBFOO'	=> 'subfoo9',
+				'SUBBAR'	=> 'subbar9',
+			)),
+			array('block2.subblock', array('SUBBAR'), array( // sub-level block, one var
+				'SUBBAR'	=> 'subbar9',
+			)),
+			array('block2.subblock.subsubblock', array(), array( // sub-sub-level block, all vars
+				'SUBSUBFOO'	=> 'subsubfoo9',
+				'SUBSUBBAR'	=> 'subsubbar9',
+			)),
+			array('block2.subblock.subsubblock', array('SUBSUBBAR'), array( // sub-sub-level block, one var
+				'SUBSUBBAR'	=> 'subsubbar9',
+			)),
+			array('block3.subblock[2]', array(), array( // sub-level, exact index, all vars
+				'SUBFOO'	=> 'subfoo2',
+				'SUBBAR'	=> 'subbar2',
+			)),
+			array('block3.subblock[2]', array('SUBBAR'), array( // sub-level, exact index, one var
+				'SUBBAR'	=> 'subbar2',
+			)),
+			array('block3.subblock[3].subsubblock[5]', array(), array( // sub-sub-level, exact index, all vars
+				'SUBSUBFOO'	=> 'subsubfoo5',
+				'SUBSUBBAR'	=> 'subsubbar5',
+			)),
+			array('block3.subblock[4].subsubblock[6]', array('SUBSUBFOO'), array( // sub-sub-level, exact index, one var
+				'SUBSUBFOO'	=> 'subsubfoo6',
+			)),
+		);
+	}
+
+	/**
+	* @dataProvider retrieve_block_vars_data
+	*/
+	public function test_retrieve_block_vars($blockname, $vararray, $result)
+	{
+		$this->assertEquals($result, $this->context->retrieve_block_vars($blockname, $vararray));
+	}
+}