diff --git a/change_log.txt b/change_log.txt
index 3fd9dd35..2773e0a0 100644
--- a/change_log.txt
+++ b/change_log.txt
@@ -1,7 +1,8 @@
  ===== 3.1.22-dev ===== (xx.xx.2015)
  04.05.2015
   - bugfix Smarty_Resource::parseResourceName incompatible with Google AppEngine (https://github.com/smarty-php/smarty/issues/22)
-  
+  - improvement use is_file() checks to avoid errors suppressed by @ which could still cause problems (https://github.com/smarty-php/smarty/issues/24)
+
  28.04.2015
   - bugfix plugins of merged subtemplates not loaded in 3.1.22-dev (forum topic 25508) 2nd fix
 
diff --git a/libs/Smarty.class.php b/libs/Smarty.class.php
index 231a62b1..dff28d21 100644
--- a/libs/Smarty.class.php
+++ b/libs/Smarty.class.php
@@ -111,7 +111,7 @@ class Smarty extends Smarty_Internal_TemplateBase
     /**
      * smarty version
      */
-    const SMARTY_VERSION = '3.1.22-dev/22';
+    const SMARTY_VERSION = '3.1.22-dev/23';
 
     /**
      * define variable scopes
diff --git a/libs/sysplugins/smarty_internal_cacheresource_file.php b/libs/sysplugins/smarty_internal_cacheresource_file.php
index cbb38e3b..72ed7692 100644
--- a/libs/sysplugins/smarty_internal_cacheresource_file.php
+++ b/libs/sysplugins/smarty_internal_cacheresource_file.php
@@ -61,8 +61,10 @@ class Smarty_Internal_CacheResource_File extends Smarty_CacheResource
             $cached->lock_id = $_lock_dir . sha1($_cache_id . $_compile_id . $_template->source->uid) . '.lock';
         }
         $cached->filepath = $_cache_dir . $_cache_id . $_compile_id . $_filepath . '.' . basename($_source_file_path) . '.php';
-        $cached->timestamp = @filemtime($cached->filepath);
-        $cached->exists = !!$cached->timestamp;
+        $cached->exists = is_file($cached->filepath);
+        if ($cached->exists) {
+            $cached->timestamp = filemtime($cached->filepath);
+        }
     }
 
     /**
@@ -74,8 +76,10 @@ class Smarty_Internal_CacheResource_File extends Smarty_CacheResource
      */
     public function populateTimestamp(Smarty_Template_Cached $cached)
     {
-        $cached->timestamp = @filemtime($cached->filepath);
-        $cached->exists = !!$cached->timestamp;
+        $cached->timestamp = $cached->exists = is_file($cached->filepath);
+        if ($cached->exists) {
+            $cached->timestamp = filemtime($cached->filepath);
+        }
     }
 
     /**
@@ -108,13 +112,13 @@ class Smarty_Internal_CacheResource_File extends Smarty_CacheResource
     {
         $obj = new Smarty_Internal_Write_File();
         if ($obj->writeFile($_template->cached->filepath, $content, $_template->smarty) === true) {
-            $_template->cached->timestamp = @filemtime($_template->cached->filepath);
-            $_template->cached->exists = !!$_template->cached->timestamp;
-            if ($_template->cached->exists) {
+            $cached = $_template->cached;
+            $cached->timestamp = $cached->exists = is_file( $cached->filepath);
+            if ($cached->exists) {
+                $cached->timestamp = filemtime($cached->filepath);
                 return true;
             }
         }
-
         return false;
     }
 
@@ -278,9 +282,12 @@ class Smarty_Internal_CacheResource_File extends Smarty_CacheResource
         } else {
             clearstatcache();
         }
-        $t = @filemtime($cached->lock_id);
-
-        return $t && (time() - $t < $smarty->locking_timeout);
+        if (is_file($cached->lock_id)) {
+            $t = @filemtime($cached->lock_id);
+            return $t && (time() - $t < $smarty->locking_timeout);
+        } else {
+            return false;
+        }
     }
 
     /**
diff --git a/libs/sysplugins/smarty_internal_extension_defaulttemplatehandler.php b/libs/sysplugins/smarty_internal_extension_defaulttemplatehandler.php
index bf25eb91..ed602920 100644
--- a/libs/sysplugins/smarty_internal_extension_defaulttemplatehandler.php
+++ b/libs/sysplugins/smarty_internal_extension_defaulttemplatehandler.php
@@ -35,8 +35,10 @@ class Smarty_Internal_Extension_DefaultTemplateHandler
         $_return = call_user_func_array($default_handler,
                                         array($source->type, $source->name, &$_content, &$_timestamp, $source->smarty));
         if (is_string($_return)) {
-            $source->timestamp = @filemtime($_return);
-            $source->exists = !!$source->timestamp;
+            $source->exists = is_file($_return);
+            if ($source->exists) {
+                $source->timestamp = filemtime($_return);
+            }
             $source->filepath = $_return;
         } elseif ($_return === true) {
             $source->content = $_content;
diff --git a/libs/sysplugins/smarty_internal_resource_file.php b/libs/sysplugins/smarty_internal_resource_file.php
index a97ed46b..95d22965 100644
--- a/libs/sysplugins/smarty_internal_resource_file.php
+++ b/libs/sysplugins/smarty_internal_resource_file.php
@@ -169,8 +169,10 @@ class Smarty_Internal_Resource_File extends Smarty_Resource
 
             $source->uid = sha1(getcwd() . $source->filepath);
             if ($source->smarty->compile_check && !isset($source->timestamp)) {
-                $source->timestamp = @filemtime($source->filepath);
-                $source->exists = !!$source->timestamp;
+                $source->timestamp = $source->exists = is_file($source->filepath);
+                if ($source->exists) {
+                    $source->timestamp = @filemtime($source->filepath);
+                }
             }
         } else {
             $source->timestamp = false;
@@ -185,8 +187,10 @@ class Smarty_Internal_Resource_File extends Smarty_Resource
      */
     public function populateTimestamp(Smarty_Template_Source $source)
     {
-        $source->timestamp = @filemtime($source->filepath);
-        $source->exists = !!$source->timestamp;
+        $source->timestamp = $source->exists = is_file($source->filepath);
+        if ($source->exists) {
+            $source->timestamp = @filemtime($source->filepath);
+        }
     }
 
     /**
diff --git a/libs/sysplugins/smarty_internal_template.php b/libs/sysplugins/smarty_internal_template.php
index 59fdae75..d47613f9 100644
--- a/libs/sysplugins/smarty_internal_template.php
+++ b/libs/sysplugins/smarty_internal_template.php
@@ -599,8 +599,8 @@ class Smarty_Internal_Template extends Smarty_Internal_TemplateBase
                         $mtime = $this->source->timestamp;
                     } else {
                         // file and php types can be checked without loading the respective resource handlers
-                        $mtime = @filemtime($_file_to_check[0]);
-                    }
+                        $mtime = is_file($_file_to_check[0]) ? @filemtime($_file_to_check[0]) : false;
+                     }
                 } elseif ($_file_to_check[2] == 'string') {
                     continue;
                 } else {
diff --git a/libs/sysplugins/smarty_internal_write_file.php b/libs/sysplugins/smarty_internal_write_file.php
index 54dbbe8f..9ecc7c0c 100644
--- a/libs/sysplugins/smarty_internal_write_file.php
+++ b/libs/sysplugins/smarty_internal_write_file.php
@@ -55,7 +55,9 @@ class Smarty_Internal_Write_File
          */
         if (Smarty::$_IS_WINDOWS) {
             // remove original file
-            @unlink($_filepath);
+            if (is_file($_filepath)) {
+                @unlink($_filepath);
+            }
             // rename tmp file
             $success = @rename($_tmp_file, $_filepath);
         } else {
@@ -63,17 +65,17 @@ class Smarty_Internal_Write_File
             $success = @rename($_tmp_file, $_filepath);
             if (!$success) {
                 // remove original file
-                @unlink($_filepath);
+                if (is_file($_filepath)) {
+                    @unlink($_filepath);
+                }
                 // rename tmp file
                 $success = @rename($_tmp_file, $_filepath);
             }
         }
-
         if (!$success) {
             error_reporting($_error_reporting);
             throw new SmartyException("unable to write file {$_filepath}");
         }
-
         if ($smarty->_file_perms !== null) {
             // set file permissions
             chmod($_filepath, $smarty->_file_perms);
diff --git a/libs/sysplugins/smarty_template_compiled.php b/libs/sysplugins/smarty_template_compiled.php
index 22d9418f..8776a091 100644
--- a/libs/sysplugins/smarty_template_compiled.php
+++ b/libs/sysplugins/smarty_template_compiled.php
@@ -130,8 +130,10 @@ class Smarty_Template_Compiled
         }
 
         $this->filepath = $_compile_dir . $_filepath . '.' . $_template->source->type . $_basename . $_cache . '.php';
-        $this->timestamp = @filemtime($this->filepath);
-        $this->exists = !!$this->timestamp;
+        $this->timestamp = $this->exists = is_file($this->filepath);
+        if ($this->exists) {
+            $this->timestamp = @filemtime($this->filepath);
+        }
     }
 
     /**
@@ -252,12 +254,12 @@ class Smarty_Template_Compiled
         if (!$_template->source->recompiled) {
             $obj = new Smarty_Internal_Write_File();
             if ($obj->writeFile($this->filepath, $code, $_template->smarty) === true) {
-                $this->timestamp = @filemtime($this->filepath);
-                $this->exists = !!$this->timestamp;
+                $this->timestamp = $this->exists = is_file($this->filepath);
                 if ($this->exists) {
+                    $this->timestamp = @filemtime($this->filepath);
                     return true;
                 }
-            }
+             }
             return false;
         } else {
             $this->code = $code;