[ticket/16891] Do not change an extension status in the middle of a request

When enabling an extension, it should be considered as not being enabled for
the entire request as if the "enabled" flag is switch during the request, the
extension will stay not loaded (same when disabling an extension).

Example when it can be an issue today : if the router is called for the first
time after enabling the extension and if the extension uses a custom route
loader (like phpbb/pages) then the router will fail because the custom route
will be found but the custom loader will not be loaded and available.

PHPBB3-16891

phpBB/config/default/container/services.yml

@@ -116,6 +116,7 @@ services:
             - '@dbal.conn'
             - '@config'
             - '@filesystem'
+            - '@router'
             - '%tables.ext%'
             - '%core.root_path%'
             - '%core.php_ext%'

phpBB/phpbb/extension/manager.php

@@ -30,9 +30,11 @@ class manager
 	protected $cache;
 	protected $php_ext;
 	protected $extensions;
+	protected $recently_changed_ext_status;
 	protected $extension_table;
 	protected $phpbb_root_path;
 	protected $cache_name;
+	protected $router;
 
 	/**
 	* Creates a manager and loads information from database
@@ -47,7 +49,7 @@ class manager
 	* @param \phpbb\cache\service $cache A cache instance or null
 	* @param string $cache_name The name of the cache variable, defaults to _ext
 	*/
-	public function __construct(ContainerInterface $container, \phpbb\db\driver\driver_interface $db, \phpbb\config\config $config, \phpbb\filesystem\filesystem_interface $filesystem, $extension_table, $phpbb_root_path, $php_ext = 'php', \phpbb\cache\service $cache = null, $cache_name = '_ext')
+	public function __construct(ContainerInterface $container, \phpbb\db\driver\driver_interface $db, \phpbb\config\config $config, \phpbb\filesystem\filesystem_interface $filesystem, \phpbb\routing\router $router, $extension_table, $phpbb_root_path, $php_ext = 'php', \phpbb\cache\service $cache = null, $cache_name = '_ext')
 	{
 		$this->cache = $cache;
 		$this->cache_name = $cache_name;
@@ -56,6 +58,7 @@ class manager
 		$this->db = $db;
 		$this->extension_table = $extension_table;
 		$this->filesystem = $filesystem;
+		$this->router = $router;
 		$this->phpbb_root_path = $phpbb_root_path;
 		$this->php_ext = $php_ext;
 
@@ -238,6 +241,12 @@ class manager
 			'ext_state'		=> serialize($state),
 		);
 
+		if ($active)
+		{
+			$this->recently_changed_ext_status[$name] = false;
+			$this->router->without_cache();
+		}
+
 		$this->update_state($name, $extension_data, $this->is_configured($name) ? 'update' : 'insert');
 
 		if ($active)
@@ -287,6 +296,12 @@ class manager
 		$state = $extension->disable_step($old_state);
 		$active = ($state !== false);
 
+		if (!$active)
+		{
+			$this->recently_changed_ext_status[$name] = true;
+			$this->router->without_cache();
+		}
+
 		$extension_data = array(
 			'ext_active'	=> $active,
 			'ext_state'		=> serialize($state),
@@ -499,6 +514,13 @@ class manager
 	*/
 	public function is_enabled($name)
 	{
+		// The extension has just been enabled and so is not loaded. When asking if it is enabled or
+		// not we should answer no to stay consistent with the status at the beginning of the request.
+		if (isset($this->recently_changed_ext_status[$name]))
+		{
+			return $this->recently_changed_ext_status[$name];
+		}
+
 		return isset($this->extensions[$name]['ext_active']) && $this->extensions[$name]['ext_active'];
 	}
 
@@ -510,6 +532,13 @@ class manager
 	*/
 	public function is_disabled($name)
 	{
+		// The extension has just been disabled and so is still loaded. When asking if it is disabled or
+		// not we should answer yes to stay consistent with the status at the beginning of the request.
+		if (isset($this->recently_changed_ext_status[$name]))
+		{
+			return $this->recently_changed_ext_status[$name];
+		}
+
 		return isset($this->extensions[$name]['ext_active']) && !$this->extensions[$name]['ext_active'];
 	}
 

phpBB/phpbb/routing/router.php

@@ -80,6 +80,11 @@ class router implements RouterInterface
 	 */
 	protected $cache_dir;
 
+	/**
+	 * @var bool
+	 */
+	protected $use_cache;
+
 	/**
 	 * Construct method
 	 *
@@ -97,6 +102,7 @@ class router implements RouterInterface
 		$this->php_ext				= $php_ext;
 		$this->context				= new RequestContext();
 		$this->cache_dir			= $cache_dir;
+		$this->use_cache			= true;
 	}
 
 	/**
@@ -176,6 +182,22 @@ class router implements RouterInterface
 		return $this->get_matcher()->match($pathinfo);
 	}
 
+	/**
+	 * Enables the use of a cached URL generator and matcher
+	 */
+	public function with_cache()
+	{
+		$this->use_cache = true;
+	}
+
+	/**
+	 * Disables the use of a cached URL generator and matcher
+	 */
+	public function without_cache()
+	{
+		$this->use_cache = false;
+	}
+
 	/**
 	 * Gets the UrlMatcher instance associated with this Router.
 	 *
@@ -198,6 +220,12 @@ class router implements RouterInterface
 	 */
 	protected function create_dumped_url_matcher()
 	{
+		if (!$this->use_cache)
+		{
+			$this->create_new_url_matcher();
+			return;
+		}
+
 		try
 		{
 			$cache = new ConfigCache("{$this->cache_dir}url_matcher.{$this->php_ext}", defined('DEBUG'));
@@ -253,6 +281,12 @@ class router implements RouterInterface
 	 */
 	protected function create_dumped_url_generator()
 	{
+		if (!$this->use_cache)
+		{
+			$this->create_new_url_generator();
+			return;
+		}
+
 		try
 		{
 			$cache = new ConfigCache("{$this->cache_dir}url_generator.{$this->php_ext}", defined('DEBUG'));