minor symfony#21389 [Debug] Remove $context arg from handleError(), preparing for PHP 7.2 (nicolas-grekas)

This PR was merged into the 2.7 branch.

Discussion
----------

[Debug] Remove $context arg from handleError(), preparing for PHP 7.2

| Q             | A
| ------------- | ---
| Branch?       | 2.7
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

PHP 7.2 will trigger deprecation notices.
See https://wiki.php.net/rfc/deprecations_php_7_2#errcontext_argument_of_error_handler

Commits
-------

83cad14 [Debug] Remove $context arg from handleError(), preparing for PHP 7.2

Author: fabpot

src/Symfony/Component/Debug/ErrorHandler.php

@@ -349,20 +349,18 @@ private function reRegister($prev)
     /**
      * Handles errors by filtering then logging them according to the configured bit fields.
      *
-     * @param int    $type      One of the E_* constants
+     * @param int    $type    One of the E_* constants
      * @param string $message
      * @param string $file
      * @param int    $line
-     * @param array  $context
-     * @param array  $backtrace
      *
      * @return bool Returns false when no handling happens so that the PHP engine can handle the error itself
      *
      * @throws \ErrorException When $this->thrownErrors requests so
      *
      * @internal
      */
-    public function handleError($type, $message, $file, $line, array $context, array $backtrace = null)
+    public function handleError($type, $message, $file, $line)
     {
         $level = error_reporting() | E_RECOVERABLE_ERROR | E_USER_ERROR | E_DEPRECATED | E_USER_DEPRECATED;
         $log = $this->loggedErrors & $type;
@@ -372,8 +370,17 @@ public function handleError($type, $message, $file, $line, array $context, array
         if (!$type || (!$log && !$throw)) {
             return $type && $log;
         }
+        $scope = $this->scopedErrors & $type;
 
-        if (isset($context['GLOBALS']) && ($this->scopedErrors & $type)) {
+        if (4 < $numArgs = func_num_args()) {
+            $context = $scope ? func_get_arg(4) : array();
+            $backtrace = 5 < $numArgs ? func_get_arg(5) : null; // defined on HHVM
+        } else {
+            $context = array();
+            $backtrace = null;
+        }
+
+        if (isset($context['GLOBALS']) && $scope) {
             $e = $context;                  // Whatever the signature of the method,
             unset($e['GLOBALS'], $context); // $context is always a reference in 5.3
             $context = $e;
@@ -389,7 +396,7 @@ public function handleError($type, $message, $file, $line, array $context, array
         }
 
         if ($throw) {
-            if (($this->scopedErrors & $type) && class_exists('Symfony\Component\Debug\Exception\ContextErrorException')) {
+            if ($scope && class_exists('Symfony\Component\Debug\Exception\ContextErrorException')) {
                 // Checking for class existence is a work around for https://bugs.php.net/42098
                 $throw = new ContextErrorException($this->levels[$type].': '.$message, 0, $type, $file, $line, $context);
             } else {
@@ -420,7 +427,7 @@ public function handleError($type, $message, $file, $line, array $context, array
         $e = compact('type', 'file', 'line', 'level');
 
         if ($type & $level) {
-            if ($this->scopedErrors & $type) {
+            if ($scope) {
                 $e['scope_vars'] = $context;
                 if ($trace) {
                     $e['stack'] = $backtrace ?: debug_backtrace(DEBUG_BACKTRACE_PROVIDE_OBJECT);