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Upgrading from an older version

Upgrading from v4 to v5

Smarty 5 adds support for PHP8.2 and drops support for PHP7.1. Smarty also adds support for new features such as the ternary operator ({$test ? $a : $b} and {$var ?: $value_if_falsy}), the null coalescing operator ({$var ?? $value_if_null}) and positional parameters for custom tags. Smarty 5 also has a brand-new extension architecture that allows you to write neat extension packs.

Namespaces

All Smarty code has been moved into the \Smarty namespace. This reduces the chance of conflicts with other (your) code.

For simple use-cases, you only need to add use Smarty\Smarty; to your script and everything will work. 

<?php
use Smarty\Smarty;
$smarty = new Smarty();

$smarty->display('homepage.tpl');
For more information, see getting started.

If you extend Smarty or use Smarty plug-ins, please review your code to see if they assume specific class or method names. E.g.: Smarty_Internal_Template is now \Smarty\Template\, SmartyException is now \Smarty\Exception.

Variable scope bubbling

Template variable scope bubbling has been simplified and made more consistent. The global scope now equals the Smarty scope in order to avoid global state side effects. Please read the documentation on language variable scope for more details.

Also, {config_load} no longer has a scope parameter, which means you can no longer load config from inside your template into the global scope (again, to avoid global state side effects). If you need to set global config, use the configLoad API method from your PHP code.

Using native PHP-functions or userland functions in your templates

You can no longer use native PHP-functions or userland functions in your templates without registering them. If you need a function in your templates, register it first.

The easiest way to do so is as follows: 

// native PHP functions used as modifiers need to be registered
$smarty->registerPlugin('modifier', 'substr', 'substr');

// userland PHP functions used as modifiers need to be registered
$smarty->registerPlugin('modifier', 'my_special_func', 'my_special_func');

But you may want to consider writing a proper extension.

Removed undocumented tags

Smarty 4 still supported some tags that have been carried over from previous version, but have never been documented.

  • {block_parent} should be replaced with {$smarty.block.parent}
  • {parent} should be replaced with {$smarty.block.parent}
  • {block_child} should be replaced with {$smarty.block.child}

  • {child} should be replaced with {$smarty.block.child}

  • {make_nocache} is no longer supported

  • {insert} is no longer supported

Removed Smarty API properties

In Smarty 4, you could make many configuration changes by directly accessing public properties on the Smarty object in PHP. In many cases, these properties have been made private, and you should now use the appropriate setter method:

  • $smarty->left_delimiter should be replaced with $smarty->getLeftDelimiter()/$smarty->setLeftDelimiter()
  • $smarty->right_delimiter should be replaced with $smarty->getRightDelimiter()/$smarty->setRightDelimiter()
  • $smarty->autoload_filters should be replaced with $smarty->registerFilter()
  • $smarty->template_dir should be replaced with $smarty->setTemplateDir()
  • $smarty->cache_dir should be replaced with $smarty->setCacheDir()
  • $smarty->compile_dir should be replaced with $smarty->setCompileDir()

Other public properties have been removed altogether, and you should no longer access them:

  • $smarty->_current_file
  • $smarty->allow_ambiguous_resources (ambiguous resources handlers should still work)
  • $smarty->registered_filters
  • $smarty->direct_access_security
  • $smarty->trusted_dir
  • $smarty->allow_php_templates
  • $smarty->php_functions
  • $smarty->php_modifiers

Backwards incompatible changes to custom plugins

We have dropped support for $smarty->plugins_dir and $smarty->use_include_path. Use $smarty->addPluginsDir() or consider writing a proper extension.

The 'insert' plugin type is no longer supported.

The $cache_attrs parameter for registered plugins is no longer supported.

Removed Smarty API methods

Search your code for the following changes:

  • $smarty->getTags() is no longer supported
  • $smarty->appendByRef() should be replaced with $smarty->append()
  • $smarty->assignByRef() should be replaced with $smarty->assign()
  • $smarty->loadPlugin() should be replaced with $smarty->registerPlugin()

Removed PHP constants

The following constants have been removed to prevent global side effects.

  • SMARTY_DIR
  • SMARTY_SYSPLUGINS_DIR
  • SMARTY_PLUGINS_DIR
  • SMARTY_MBSTRING
  • SMARTY_HELPER_FUNCTIONS_LOADED

Other changes

  • Smarty now always runs in multibyte mode. Make sure you use the PHP multibyte extension in production for optimal performance.
  • Generated <script> tags lo longer have deprecated type="text/javascript" or language="Javascript" attributes
  • Smarty will throw a compiler exception instead of silently ignoring a modifier on a function call, like this: {include|dot:"x-template-id" file="included.dot.tpl"}
  • The ::getFile() method of a CompilerException will now return the full path of the template being compiled, if possible. This used to be 'file:relative_dir/filename.tpl'.

Upgrading from v3 to v4

Smarty 4 is mostly identical to Smarty 3. Most notably, it adds support for PHP8 and drops support for PHP7.0 and below. Additionally, some deprecated features that have long been discouraged have been dropped from the language.

Muting PHP8 warnings

If you simultaneously upgrade Smarty to v4 van PHP to v8, you may notice your error logs filling up with warnings about undefined or null template vars due to a change in how PHP handles these. This may be helpful to spot errors, but if you find this annoying, you can use $smarty->muteUndefinedOrNullWarnings() to make Smarty convert these warnings into notices.

ASP tags

You can no longer user ASP-style tags like <% %> and <%= %> in your templates. Replace them with {...} tags.

SmartyBC

Check your codebase for SmartyBC. We have dropped deprecated API calls that where only accessible through the SmartyBC class.

No more embedded PHP

We have completely dropped support for {php} and {include_php} tags and embedded PHP in templates. Check your templates for this, and rewrite any embedded PHP blocks, by moving logic to your PHP files or by creating a custom tag.

Other changes

Search your code for the following changes:

  • SMARTY_RESOURCE_CHAR_SET and SMARTY_RESOURCE_DATE_FORMAT constants have been removed
  • Smarty::muteExpectedErrors and Smarty::unmuteExpectedErrors API methods have been removed
  • Smarty::getVariable method has been removed. Use Smarty::getTemplateVars instead.
  • Smarty::registerResource no longer accepts an array of callback functions