feature #10921 [Debug] generic ErrorHandler (nicolas-grekas)

This PR was merged into the 2.6-dev branch.

Discussion
----------

[Debug] generic ErrorHandler

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | minor, see updated tests
| Deprecations? | yes
| Tests pass?   | yes
| Fixed tickets | none
| License       | MIT
| Doc PR        | none

The proposed goal of this PR is to build a class that can serve as a foundation for a standard error handler, shared with other projects and not only used by the FrameworkBundle.

This is a merge of my previous work on the subject (https://github.com/nicolas-grekas/Patchwork-Error-Logger/blob/master/class/Patchwork/PHP/InDepthErrorHandler.php) and recent improvements of error handling in Symfony's Debug\ErrorHandler.

ExceptionHandler has a new AbstractExceptionHandler base class that factors out the handling of fatal errors casted to exceptions.

ErrorHandler is introduced, which provides five bit fields that control how errors are handled:

- thrownErrors: errors thrown as ContextErrorException
- loggedErrors: logged errors, when not @-silenced
- scopedErrors: errors thrown or logged with their local context
- tracedErrors: errors logged with their trace, only once for repeated errors
- screamedErrors: never @-silenced errors

Each error level can be logged by a dedicated PSR-3 logger object.
Screaming only applies to logging.
Throwing takes precedence over logging.
Uncaught exceptions are logged as E_ERROR.
E_DEPRECATED and E_USER_DEPRECATED levels never throw.
E_RECOVERABLE_ERROR and E_USER_ERROR levels always throw.
Non catchable errors that can be detected at shutdown time are logged when the scream bit field allows so.
As errors have a performance cost, repeated errors are all logged, so that the developer
can see them and weight them as more important to fix than others of the same level.

- [x] build a more generic ErrorHandler
- [x] update service/listeners definitions to take advantage of the new interface of ErrorHandler
- [x] add phpdocs
- [x] add tests

Commits
-------

1701447 [Debug] update FrameworkBundle and HttpKernel for new ErrorHandler
839e9ac [Debug] generalized ErrorHandler

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php

@@ -61,6 +61,9 @@ public function load(array $configs, ContainerBuilder $container)
         if ($container->getParameter('kernel.debug')) {
             $loader->load('debug.xml');
 
+            $definition = $container->findDefinition('debug.debug_handlers_listener');
+            $definition->replaceArgument(0, array(new Reference('http_kernel', ContainerInterface::NULL_ON_INVALID_REFERENCE), 'terminateWithException'));
+
             $definition = $container->findDefinition('http_kernel');
             $definition->replaceArgument(2, new Reference('debug.controller_resolver'));
 
@@ -69,6 +72,9 @@ public function load(array $configs, ContainerBuilder $container)
             $definition->setPublic(false);
             $container->setDefinition('debug.event_dispatcher.parent', $definition);
             $container->setAlias('event_dispatcher', 'debug.event_dispatcher');
+        } else {
+            $definition = $container->findDefinition('debug.debug_handlers_listener');
+            $definition->replaceArgument(2, E_COMPILE_ERROR | E_PARSE | E_ERROR | E_CORE_ERROR);
         }
 
         $configuration = $this->getConfiguration($configs, $container);

src/Symfony/Bundle/FrameworkBundle/Resources/config/debug.xml

@@ -9,7 +9,6 @@
         <parameter key="debug.stopwatch.class">Symfony\Component\Stopwatch\Stopwatch</parameter>
         <parameter key="debug.container.dump">%kernel.cache_dir%/%kernel.container_class%.xml</parameter>
         <parameter key="debug.controller_resolver.class">Symfony\Component\HttpKernel\Controller\TraceableControllerResolver</parameter>
-        <parameter key="debug.debug_handlers_listener.class">Symfony\Component\HttpKernel\EventListener\DebugHandlersListener</parameter>
     </parameters>
 
     <services>
@@ -26,27 +25,5 @@
             <argument type="service" id="controller_resolver" />
             <argument type="service" id="debug.stopwatch" />
         </service>
-
-        <service id="debug.deprecation_logger_listener" class="%debug.errors_logger_listener.class%">
-            <tag name="kernel.event_subscriber" />
-            <tag name="monolog.logger" channel="deprecation" />
-            <argument>deprecation</argument>
-            <argument type="service" id="logger" on-invalid="null" />
-        </service>
-
-        <service id="debug.scream_logger_listener" class="%debug.errors_logger_listener.class%">
-            <tag name="kernel.event_subscriber" />
-            <tag name="monolog.logger" channel="scream" />
-            <argument>scream</argument>
-            <argument type="service" id="logger" on-invalid="null" />
-        </service>
-
-        <service id="debug.debug_handlers_listener" class="%debug.debug_handlers_listener.class%">
-            <tag name="kernel.event_subscriber" />
-            <argument type="collection">
-                <argument type="service" id="http_kernel" on-invalid="null" />
-                <argument>terminateWithException</argument>
-            </argument>
-        </service>
     </services>
 </container>

src/Symfony/Bundle/FrameworkBundle/Resources/config/debug_prod.xml

@@ -5,15 +5,17 @@
     xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">
 
     <parameters>
-        <parameter key="debug.errors_logger_listener.class">Symfony\Component\HttpKernel\EventListener\ErrorsLoggerListener</parameter>
+        <parameter key="debug.debug_handlers_listener.class">Symfony\Component\HttpKernel\EventListener\DebugHandlersListener</parameter>
     </parameters>
 
     <services>
-        <service id="debug.emergency_logger_listener" class="%debug.errors_logger_listener.class%">
+        <service id="debug.debug_handlers_listener" class="%debug.debug_handlers_listener.class%">
             <tag name="kernel.event_subscriber" />
-            <tag name="monolog.logger" channel="emergency" />
-            <argument>emergency</argument>
+            <tag name="monolog.logger" channel="php" />
+            <argument /><!-- Exception handler -->
             <argument type="service" id="logger" on-invalid="null" />
+            <argument /><!-- Log levels map for enabled error levels -->
+            <argument>%kernel.debug%</argument>
         </service>
     </services>
 </container>

src/Symfony/Bundle/FrameworkBundle/composer.json

@@ -21,7 +21,7 @@
         "symfony/config" : "~2.4",
         "symfony/event-dispatcher": "~2.5",
         "symfony/http-foundation": "~2.4",
-        "symfony/http-kernel": "~2.5",
+        "symfony/http-kernel": "~2.6",
         "symfony/filesystem": "~2.3",
         "symfony/routing": "~2.2",
         "symfony/security-core": "~2.4",

src/Symfony/Bundle/WebProfilerBundle/Resources/views/Collector/logger.html.twig

@@ -105,7 +105,7 @@
 
 
 {% macro display_message(log_index, log) %}
-    {% if constant('Symfony\\Component\\HttpKernel\\Debug\\ErrorHandler::TYPE_DEPRECATION') == log.context.type|default(0) %}
+    {% if log.context.level is defined and log.context.type is defined and (constant('E_DEPRECATED') == log.context.type or constant('E_USER_DEPRECATED') == log.context.type) %}
         DEPRECATION -  {{ log.message }}
         {% set id = 'sf-call-stack-' ~ log_index %}
         <a href="#" onclick="Sfjs.toggle('{{ id }}', document.getElementById('{{ id }}-on'), document.getElementById('{{ id }}-off')); return false;">

src/Symfony/Component/Debug/CHANGELOG.md

@@ -4,6 +4,8 @@ CHANGELOG
 2.6.0
 -----
 
+* generalized ErrorHandler and ExceptionHandler,
+  with some new methods and others deprecated
 * enhanced error messages for uncaught exceptions
 
 2.5.0

src/Symfony/Component/Debug/Debug.php

@@ -39,15 +39,23 @@ public static function enable($errorReportingLevel = null, $displayErrors = true
 
         static::$enabled = true;
 
-        error_reporting(-1);
+        if (null !== $errorReportingLevel) {
+            error_reporting($errorReportingLevel);
+        } else {
+            error_reporting(-1);
+        }
 
-        ErrorHandler::register($errorReportingLevel, $displayErrors);
         if ('cli' !== php_sapi_name()) {
+            ini_set('display_errors', 0);
             ExceptionHandler::register();
-        // CLI - display errors only if they're not already logged to STDERR
         } elseif ($displayErrors && (!ini_get('log_errors') || ini_get('error_log'))) {
+            // CLI - display errors only if they're not already logged to STDERR
             ini_set('display_errors', 1);
         }
+        $handler = ErrorHandler::register();
+        if (!$displayErrors) {
+            $handler->throwAt(0, true);
+        }
 
         DebugClassLoader::enable();
     }

src/Symfony/Component/Debug/DebugClassLoader.php

@@ -78,7 +78,7 @@ public function getClassLoader()
     public static function enable()
     {
         // Ensures we don't hit https://bugs.php.net/42098
-        class_exists(__NAMESPACE__.'\ErrorHandler', true);
+        class_exists('Symfony\Component\Debug\ErrorHandler');
 
         if (!is_array($functions = spl_autoload_functions())) {
             return;