API: Clean up uncaught exception backtrace output

[lhc/web/wiklou.git] / includes / exception / MWExceptionHandler.php

diff --git a/includes/exception/MWExceptionHandler.php b/includes/exception/MWExceptionHandler.php
index 9db04cb..83801b6 100644 (file)
--- a/includes/exception/MWExceptionHandler.php
+++ b/includes/exception/MWExceptionHandler.php
@@ -24,12 +24,24 @@
  */
 class MWExceptionHandler {
 
+       protected static $reservedMemory;
+       protected static $fatalErrorTypes = array(
+               E_ERROR, E_PARSE, E_CORE_ERROR, E_COMPILE_ERROR, E_USER_ERROR,
+               /* HHVM's FATAL_ERROR level */ 16777217,
+       );
+
        /**
         * Install handlers with PHP.
         */
        public static function installHandler() {
                set_exception_handler( array( 'MWExceptionHandler', 'handleException' ) );
                set_error_handler( array( 'MWExceptionHandler', 'handleError' ) );
+
+               // Reserve 16k of memory so we can report OOM fatals
+               self::$reservedMemory = str_repeat( ' ', 16384 );
+               register_shutdown_function(
+                       array( 'MWExceptionHandler', 'handleFatalError' )
+               );
        }
 
        /**
@@ -194,6 +206,9 @@ class MWExceptionHandler {
                        case E_USER_DEPRECATED:
                                $levelName = 'Deprecated';
                                break;
+                       case /* HHVM's FATAL_ERROR */ 16777217:
+                               $levelName = 'Fatal';
+                               break;
                        default:
                                $levelName = 'Unknown error';
                                break;
@@ -207,6 +222,44 @@ class MWExceptionHandler {
                return false;
        }
 
+
+       /**
+        * Look for a fatal error as the cause of the request termination and log
+        * as an exception.
+        *
+        * Special handling is included for missing class errors as they may
+        * indicate that the user needs to install 3rd-party libraries via
+        * Composer or other means.
+        *
+        * @since 1.25
+        */
+       public static function handleFatalError() {
+               self::$reservedMemory = null;
+               $lastError = error_get_last();
+
+               if ( $lastError &&
+                       isset( $lastError['type'] ) &&
+                       in_array( $lastError['type'], self::$fatalErrorTypes )
+               ) {
+                       $msg = "Fatal Error: {$lastError['message']}";
+                       // HHVM: Class undefined: foo
+                       // PHP5: Class 'foo' not found
+                       if ( preg_match( "/Class (undefined: \w+|'\w+' not found)/",
+                               $lastError['message']
+                       ) ) {
+                               $msg = <<<TXT
+{$msg}
+
+MediaWiki or an installed extension requires this class but it is not embedded directly in MediaWiki's git repository and must be installed separately by the end user.
+
+Please see <a href="https://www.mediawiki.org/wiki/Download_from_Git#Fetch_external_libraries">mediawiki.org</a> for help on installing the required components.
+TXT;
+                       }
+                       $e = new ErrorException( $msg, 0, $lastError['type'] );
+                       self::logError( $e );
+               }
+       }
+
        /**
         * Generate a string representation of an exception's stack trace
         *