Merge branch 'master' into bugfix/caching_attributes_and_cacheable_plugin

Fixes #457

change_log.txt

@@ -1,4 +1,5 @@
  - fix foreachelse on arrayiterators https://github.com/smarty-php/smarty/issues/506
+ - throw SmartyException when setting caching attributes for cacheable plugin https://github.com/smarty-php/smarty/issues/457
  - fix errors that occured where isset was replaced with null check such as https://github.com/smarty-php/smarty/issues/453
 
 ===== 3.1.34 release ===== 05.11.2019

libs/sysplugins/smarty_internal_method_registerplugin.php

@@ -48,6 +48,8 @@ class Smarty_Internal_Method_RegisterPlugin
             throw new SmartyException("Plugin tag '{$name}' already registered");
         } elseif (!is_callable($callback)) {
             throw new SmartyException("Plugin '{$name}' not callable");
+        } elseif ($cacheable && $cache_attr) {
+            throw new SmartyException("Cannot set caching attributes for plugin '{$name}' when it is cacheable.");
         } else {
             $smarty->registered_plugins[ $type ][ $name ] = array($callback, (bool)$cacheable, (array)$cache_attr);
         }