From 427a5122d55f06c861277297411f7e39a03a703c Mon Sep 17 00:00:00 2001
From: Igor Wiedler <igor@wiedler.ch>
Date: Tue, 26 Apr 2011 02:09:51 +0200
Subject: [PATCH] [feature/template-engine] Fix negative variable expressions

compile_tag_if had the flawed approach of adding an isset statement for
all variables to the beginning of the if. This fails for negative
expressions, and checking those takes a considerable effort.

The easier solution is to make the variable expression itself
conditional, defaulting to null if it is not set.

Thanks to naderman for the solution.

PHPBB3-9726
---
 phpBB/includes/template_compile.php | 15 ++++-----------
 tests/template/template_test.php    |  2 +-
 tests/template/templates/basic.html |  3 +++
 tests/template/templates/if.html    |  2 +-
 4 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/phpBB/includes/template_compile.php b/phpBB/includes/template_compile.php
index 9a8bc05343..3f8a028e25 100644
--- a/phpBB/includes/template_compile.php
+++ b/phpBB/includes/template_compile.php
@@ -408,7 +408,7 @@ class phpbb_template_filter extends php_user_filter
 	* some adaptions for our block level methods
 	* @access private
 	*/
-	private function compile_expression($tag_args, &$vars = array())
+	private function compile_expression($tag_args)
 	{
 		$match = array();
 		preg_match_all('/(?:
@@ -553,14 +553,14 @@ class phpbb_template_filter extends php_user_filter
 
 								default:
 									$token = $this->generate_block_data_ref(substr($varrefs[1], 0, -1), true, $varrefs[2]) . '[\'' . $varrefs[3] . '\']';
-									$vars[$token] = true;
+									$token = '(isset(' . $token . ') ? ' . $token . ' : null)';
 								break;
 							}
 						}
 						else
 						{
 							$token = ($varrefs[2]) ? '$_tpldata[\'DEFINE\'][\'.\'][\'' . $varrefs[3] . '\']' : '$_rootref[\'' . $varrefs[3] . '\']';
-							$vars[$token] = true;
+							$token = '(isset(' . $token . ') ? ' . $token . ' : null)';
 						}
 
 					}
@@ -601,17 +601,10 @@ class phpbb_template_filter extends php_user_filter
 
 	private function compile_tag_if($tag_args, $elseif)
 	{
-		$vars = array();
-
-		$tokens = $this->compile_expression($tag_args, $vars);
+		$tokens = $this->compile_expression($tag_args);
 
 		$tpl = ($elseif) ? '} else if (' : 'if (';
 
-		if (!empty($vars))
-		{
-			$tpl .= '(isset(' . implode(') && isset(', array_keys($vars)) . ')) && ';
-		}
-
 		$tpl .= implode(' ', $tokens);
 		$tpl .= ') { ';
 
diff --git a/tests/template/template_test.php b/tests/template/template_test.php
index 4304035192..0a46ff4d23 100644
--- a/tests/template/template_test.php
+++ b/tests/template/template_test.php
@@ -91,7 +91,7 @@ class phpbb_template_template_test extends phpbb_test_case
 				array(),
 				array(),
 				array(),
-				"pass\npass\n<!-- DUMMY var -->",
+				"pass\npass\npass\n<!-- DUMMY var -->",
 			),
 			array(
 				'variable.html',
diff --git a/tests/template/templates/basic.html b/tests/template/templates/basic.html
index c1dd690260..e5c6f280fb 100644
--- a/tests/template/templates/basic.html
+++ b/tests/template/templates/basic.html
@@ -16,5 +16,8 @@ fail
 <!-- BEGINELSE -->
 pass
 <!-- END empty -->
+<!-- IF not S_EMPTY -->
+pass
+<!-- ENDIF -->
 
 <!-- DUMMY var -->
diff --git a/tests/template/templates/if.html b/tests/template/templates/if.html
index 41ff024779..eed431019e 100644
--- a/tests/template/templates/if.html
+++ b/tests/template/templates/if.html
@@ -6,6 +6,6 @@
 03
 <!-- ENDIF -->
 
-<!-- IF (S_VALUE > S_OTHER_VALUE) -->
+<!-- IF S_VALUE and S_OTHER_VALUE and (S_VALUE > S_OTHER_VALUE) -->
 04
 <!-- ENDIF -->