default modifier uses empty instead of @ error suppression modifier when testing a variable

Fixes #336

.gitignore

@@ -11,3 +11,4 @@ utilies/*.php
 phpunit*
 vendor/*
 composer.lock
+/composer.phar

CHANGELOG.md

@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 
 ### Changed
+- default modifier uses empty instead of @ error suppression modifier when testing a variable https://github.com/smarty-php/smarty/issues/336
 - modifier escape now triggers a E_USER_NOTICE when an unsupported escape type is used https://github.com/smarty-php/smarty/pull/649
 
 ## [3.1.39] - 2021-02-17

libs/plugins/modifiercompiler.default.php

@@ -18,7 +18,7 @@
  *
  * @return string with compiled code
  */
-function smarty_modifiercompiler_default($params)
+function smarty_modifiercompiler_default($params, Smarty_Internal_TemplateCompilerBase $compiler)
 {
     $output = $params[ 0 ];
     if (!isset($params[ 1 ])) {
@@ -26,7 +26,13 @@ function smarty_modifiercompiler_default($params)
     }
     array_shift($params);
     foreach ($params as $param) {
-        $output = '(($tmp = @' . $output . ')===null||$tmp===\'\' ? ' . $param . ' : $tmp)';
+
+        if ($compiler->syntaxMatchesVariable($output)) {
+            $output = '(empty(' . $output . ') ? ' . $param . ' : ' . $output . ')';
+        } else {
+            $output = '(($tmp = ' . $output . ')===null||$tmp===\'\' ? ' . $param . ' : $tmp)';
+        }
+
     }
     return $output;
 }

libs/sysplugins/smarty_internal_templatecompilerbase.php

@@ -674,7 +674,7 @@ abstract class Smarty_Internal_TemplateCompilerBase
 	 * @param $string
 	 * @return bool
 	 */
-	private function syntaxMatchesVariable($string) {
+	public function syntaxMatchesVariable($string) {
     	static $regex_pattern = '/^\$[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*((->)[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*|\[.*]*\])*$/';
     	return 1 === preg_match($regex_pattern, trim($string));
     }

tests/UnitTests/A_Core/MuteExpectedErrors/MuteExpectedErrorsTest.php

@@ -64,10 +64,10 @@ class MuteExpectedErrorsTest extends PHPUnit_Smarty
         $this->smarty->clearCompiledTemplate('default.tpl');
         $this->smarty->fetch('default.tpl');
 
-        $this->assertEquals(Smarty::$_IS_WINDOWS ? 2 : 2, count($this->_errors));
+        $this->assertEquals(0, count($this->_errors));
 
         @filemtime('ckxladanwijicajscaslyxck');
-        $this->assertEquals(Smarty::$_IS_WINDOWS ? 3 : 3, count($this->_errors));
+        $this->assertEquals(1, count($this->_errors));
 
         restore_error_handler();
     }
@@ -112,11 +112,11 @@ class MuteExpectedErrorsTest extends PHPUnit_Smarty
         $this->smarty->clearCompiledTemplate('default.tpl');
         $this->smarty->fetch('default.tpl');
 
-        $this->assertEquals(Smarty::$_IS_WINDOWS ? 2 : 2, count($this->_errors));
+        $this->assertEquals(0, count($this->_errors));
 
         @filemtime('ckxladanwijicajscaslyxck');
         $error = array(__FILE__ . ' line ' . (__LINE__ - 1));
-        $this->assertEquals(Smarty::$_IS_WINDOWS ? 3 : 3, count($this->_errors));
+        $this->assertEquals(1, count($this->_errors));
 
         restore_error_handler();
     }

tests/UnitTests/ResourceTests/File/FileResourceTest.php

@@ -110,6 +110,9 @@ class FileResourceTest extends PHPUnit_Smarty
         );
     }
 
+    /**
+     * @doesNotPerformAssertions
+     */
     public function testGetCompiledTimestampPrepare()
     {
         $tpl = $this->smarty->createTemplate('helloworld.tpl');
@@ -142,6 +145,9 @@ class FileResourceTest extends PHPUnit_Smarty
         $this->assertTrue($tpl->mustCompile());
     }
 
+    /**
+     * @doesNotPerformAssertions
+     */
     public function testMustCompileTouchedSourcePrepare()
     {
         // touch to prepare next test

tests/UnitTests/ResourceTests/Php/PhpResourceTest.php

@@ -161,7 +161,7 @@ class PhpResourceTest extends PHPUnit_Smarty
      *
      * @runInSeparateProcess
      * @preserveGlobalState disabled
-     *
+     * @doesNotPerformAssertions
      */
     public function testIsCachedTouchedSourcePrepare()
     {
@@ -212,6 +212,7 @@ class PhpResourceTest extends PHPUnit_Smarty
 
     /**
      * test $smarty->is_cached
+     * @doesNotPerformAssertions
      */
     public function testSmartyIsCachedPrepare()
     {

tests/UnitTests/TemplateSource/Comments/templates_tmp/testComments_T1.tpl

@@ -0,0 +1 @@
+{* this is a comment *}

tests/UnitTests/TemplateSource/Comments/templates_tmp/testComments_T10.tpl

@@ -0,0 +1,7 @@
+=
+{* comment *}
+{* comment *}
+    b
+{* comment *}
+{* comment *}
+=

tests/UnitTests/TemplateSource/Comments/templates_tmp/testComments_T11.tpl

@@ -0,0 +1,7 @@
+=
+a
+{* comment 1 *}
+{* comment 2 *}
+{* comment 3 *}
+b
+=

tests/UnitTests/TemplateSource/Comments/templates_tmp/testComments_T12.tpl

@@ -0,0 +1,7 @@
+=
+a
+{* comment 1 *}
+ {* comment 2 *}
+{* comment 3 *}
+b
+=

tests/UnitTests/TemplateSource/Comments/templates_tmp/testComments_T13.tpl

@@ -0,0 +1,7 @@
+=
+a
+{* comment 1 *}
+{* comment 2 *} 
+{* comment 3 *}
+b
+=

tests/UnitTests/TemplateSource/Comments/templates_tmp/testComments_T14.tpl

@@ -0,0 +1,7 @@
+=
+a
+{* comment 1 *}
+ {* comment 2 *} 
+{* comment 3 *}
+b
+=

tests/UnitTests/TemplateSource/Comments/templates_tmp/testComments_T2.tpl

@@ -0,0 +1 @@
+{* another $foo comment *}

tests/UnitTests/TemplateSource/Comments/templates_tmp/testComments_T3.tpl

@@ -0,0 +1 @@
+{* another  comment *}some in between{* another  comment *}

tests/UnitTests/TemplateSource/Comments/templates_tmp/testComments_T4.tpl

@@ -0,0 +1,2 @@
+{* multi line 
+ comment *}

tests/UnitTests/TemplateSource/Comments/templates_tmp/testComments_T5.tpl

@@ -0,0 +1 @@
+{* /* foo * / *}

tests/UnitTests/TemplateSource/Comments/templates_tmp/testComments_T6.tpl

@@ -0,0 +1,2 @@
+A{* comment *}B
+C

tests/UnitTests/TemplateSource/Comments/templates_tmp/testComments_T7.tpl

@@ -0,0 +1,3 @@
+D{* comment *}
+{* comment *}E
+F

tests/UnitTests/TemplateSource/Comments/templates_tmp/testComments_T8.tpl

@@ -0,0 +1,2 @@
+G{* multi 
+line *}H

tests/UnitTests/TemplateSource/Comments/templates_tmp/testComments_T9.tpl

@@ -0,0 +1,3 @@
+I{* multi 
+line *}
+J

tests/UnitTests/TemplateSource/TagTests/PluginFunction/PluginFunctionHtmlImageTest.php

@@ -20,6 +20,9 @@ class PluginFunctionHtmlImageTest extends PHPUnit_Smarty
         $this->setUpSmarty(dirname(__FILE__));
     }
 
+    /**
+     * @doesNotPerformAssertions
+     */
     public function testFoo()
     {
         // TODO: UnitTests for {html_image}

tests/UnitTests/TemplateSource/X_Scopes/ScopeTest.php

@@ -291,6 +291,9 @@ class ScopeTest extends PHPUnit_Smarty
                            'no  smarty', $i ++,),);
     }
 
+    /**
+     * @doesNotPerformAssertions
+     */
     public function testFunctionScope()
     {
         $this->smarty->assign('scope', 'none');