Increased the reserved memory from 10k to 32k

The ErrorHandler's job includes handling out of memory (OOM) exceptions,
therefore it is imoprtant that that feature works. In the current state,
when handling OOM exceptions, the error handler produces an OOM error
itself, because the old 10k reserve is apparently not enough anymore.
To mitigate that, the reserved memory gets bumped to 32k (which is enouogh).

ErrorHandler.php

@@ -119,7 +119,7 @@ class ErrorHandler
     public static function register(self $handler = null, $replace = true)
     {
         if (null === self::$reservedMemory) {
-            self::$reservedMemory = str_repeat('x', 10240);
+            self::$reservedMemory = str_repeat('x', 32768);
             register_shutdown_function(__CLASS__.'::handleFatalError');
         }
 

Exception/FatalErrorException.php

@@ -35,8 +35,7 @@ class FatalErrorException extends \ErrorException
 
             $this->setTrace($trace);
         } elseif (null !== $traceOffset) {
-            if (\function_exists('xdebug_get_function_stack')) {
-                $trace = xdebug_get_function_stack();
+            if (\function_exists('xdebug_get_function_stack') && $trace = @xdebug_get_function_stack()) {
                 if (0 < $traceOffset) {
                     array_splice($trace, -$traceOffset);
                 }

Exception/FatalThrowableError.php

@@ -26,7 +26,7 @@ class FatalThrowableError extends FatalErrorException
 
     public function __construct(\Throwable $e)
     {
-        $this->originalClassName = get_debug_type($e);
+        $this->originalClassName = \get_class($e);
 
         if ($e instanceof \ParseError) {
             $severity = \E_PARSE;

Exception/FlattenException.php

@@ -67,7 +67,7 @@ class FlattenException
         $e->setStatusCode($statusCode);
         $e->setHeaders($headers);
         $e->setTraceFromThrowable($exception);
-        $e->setClass($exception instanceof FatalThrowableError ? $exception->getOriginalClassName() : get_debug_type($exception));
+        $e->setClass($exception instanceof FatalThrowableError ? $exception->getOriginalClassName() : \get_class($exception));
         $e->setFile($exception->getFile());
         $e->setLine($exception->getLine());
 

FatalErrorHandler/UndefinedMethodFatalErrorHandler.php

@@ -40,7 +40,7 @@ class UndefinedMethodFatalErrorHandler implements FatalErrorHandlerInterface
 
         $message = sprintf('Attempted to call an undefined method named "%s" of class "%s".', $methodName, $className);
 
-        if (!class_exists($className) || null === $methods = get_class_methods($className)) {
+        if ('' === $methodName || !class_exists($className) || null === $methods = get_class_methods($className)) {
             // failed to get the class or its methods on which an unknown method was called (for example on an anonymous class)
             return new UndefinedMethodException($message, $exception);
         }

README.md

@@ -12,7 +12,7 @@ Getting Started
 ---------------
 
 ```
-$ composer install symfony/debug
+$ composer require symfony/debug
 ```
 
 ```php
@@ -24,7 +24,7 @@ Debug::enable();
 Resources
 ---------
 
-  * [Contributing](https://symfony.com/doc/current/contributing/index.html)
-  * [Report issues](https://github.com/symfony/symfony/issues) and
-    [send Pull Requests](https://github.com/symfony/symfony/pulls)
-    in the [main Symfony repository](https://github.com/symfony/symfony)
+ * [Contributing](https://symfony.com/doc/current/contributing/index.html)
+ * [Report issues](https://github.com/symfony/symfony/issues) and
+   [send Pull Requests](https://github.com/symfony/symfony/pulls)
+   in the [main Symfony repository](https://github.com/symfony/symfony)

Tests/FatalErrorHandler/UndefinedMethodFatalErrorHandlerTest.php

@@ -48,6 +48,15 @@ class UndefinedMethodFatalErrorHandlerTest extends TestCase
                 ],
                 'Attempted to call an undefined method named "what" of class "SplObjectStorage".',
             ],
+            [
+                [
+                    'type' => 1,
+                    'line' => 12,
+                    'file' => 'foo.php',
+                    'message' => 'Call to undefined method SplObjectStorage::()',
+                ],
+                'Attempted to call an undefined method named "" of class "SplObjectStorage".',
+            ],
             [
                 [
                     'type' => 1,

Tests/phpt/exception_rethrown.phpt

@@ -14,7 +14,7 @@ require $vendor.'/vendor/autoload.php';
 if (true) {
     class TestLogger extends \Psr\Log\AbstractLogger
     {
-        public function log($level, $message, array $context = [])
+        public function log($level, $message, array $context = []): void
         {
             echo $message, "\n";
         }

composer.json

@@ -17,8 +17,7 @@
     ],
     "require": {
         "php": ">=7.1.3",
-        "psr/log": "~1.0",
-        "symfony/polyfill-php80": "^1.15"
+        "psr/log": "^1|^2|^3"
     },
     "conflict": {
         "symfony/http-kernel": "<3.4"