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File Content: `ErrorHandler.php`

<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\Debug;

use Psr\Log\LoggerInterface;
use Psr\Log\LogLevel;
use Symfony\Component\Debug\Exception\ContextErrorException;
use Symfony\Component\Debug\Exception\FatalErrorException;
use Symfony\Component\Debug\Exception\FatalThrowableError;
use Symfony\Component\Debug\Exception\OutOfMemoryException;
use Symfony\Component\Debug\Exception\SilencedErrorContext;
use Symfony\Component\Debug\FatalErrorHandler\ClassNotFoundFatalErrorHandler;
use Symfony\Component\Debug\FatalErrorHandler\FatalErrorHandlerInterface;
use Symfony\Component\Debug\FatalErrorHandler\UndefinedFunctionFatalErrorHandler;
use Symfony\Component\Debug\FatalErrorHandler\UndefinedMethodFatalErrorHandler;

/**
 * A generic ErrorHandler for the PHP engine.
 *
 * Provides five bit fields that control how errors are handled:
 * - thrownErrors: errors thrown as \ErrorException
 * - loggedErrors: logged errors, when not @-silenced
 * - scopedErrors: errors thrown or logged with their local context
 * - tracedErrors: errors logged with their stack trace
 * - 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.
 *
 * @author Nicolas Grekas <p@tchwork.com>
 * @author Grégoire Pineau <lyrixx@lyrixx.info>
 */
class ErrorHandler
{
    private $levels = [
        \E_DEPRECATED => 'Deprecated',
        \E_USER_DEPRECATED => 'User Deprecated',
        \E_NOTICE => 'Notice',
        \E_USER_NOTICE => 'User Notice',
        \E_STRICT => 'Runtime Notice',
        \E_WARNING => 'Warning',
        \E_USER_WARNING => 'User Warning',
        \E_COMPILE_WARNING => 'Compile Warning',
        \E_CORE_WARNING => 'Core Warning',
        \E_USER_ERROR => 'User Error',
        \E_RECOVERABLE_ERROR => 'Catchable Fatal Error',
        \E_COMPILE_ERROR => 'Compile Error',
        \E_PARSE => 'Parse Error',
        \E_ERROR => 'Error',
        \E_CORE_ERROR => 'Core Error',
    ];

    private $loggers = [
        \E_DEPRECATED => [null, LogLevel::INFO],
        \E_USER_DEPRECATED => [null, LogLevel::INFO],
        \E_NOTICE => [null, LogLevel::WARNING],
        \E_USER_NOTICE => [null, LogLevel::WARNING],
        \E_STRICT => [null, LogLevel::WARNING],
        \E_WARNING => [null, LogLevel::WARNING],
        \E_USER_WARNING => [null, LogLevel::WARNING],
        \E_COMPILE_WARNING => [null, LogLevel::WARNING],
        \E_CORE_WARNING => [null, LogLevel::WARNING],
        \E_USER_ERROR => [null, LogLevel::CRITICAL],
        \E_RECOVERABLE_ERROR => [null, LogLevel::CRITICAL],
        \E_COMPILE_ERROR => [null, LogLevel::CRITICAL],
        \E_PARSE => [null, LogLevel::CRITICAL],
        \E_ERROR => [null, LogLevel::CRITICAL],
        \E_CORE_ERROR => [null, LogLevel::CRITICAL],
    ];

    private $thrownErrors = 0x1FFF; // E_ALL - E_DEPRECATED - E_USER_DEPRECATED
    private $scopedErrors = 0x1FFF; // E_ALL - E_DEPRECATED - E_USER_DEPRECATED
    private $tracedErrors = 0x77FB; // E_ALL - E_STRICT - E_PARSE
    private $screamedErrors = 0x55; // E_ERROR + E_CORE_ERROR + E_COMPILE_ERROR + E_PARSE
    private $loggedErrors = 0;
    private $traceReflector;

    private $isRecursive = 0;
    private $isRoot = false;
    private $exceptionHandler;
    private $bootstrappingLogger;

    private static $reservedMemory;
    private static $stackedErrors = [];
    private static $stackedErrorLevels = [];
    private static $toStringException = null;
    private static $silencedErrorCache = [];
    private static $silencedErrorCount = 0;
    private static $exitCode = 0;

    /**
     * Registers the error handler.
     *
     * @param self|null $handler The handler to register
     * @param bool      $replace Whether to replace or not any existing handler
     *
     * @return self The registered error handler
     */
    public static function register(self $handler = null, $replace = true)
    {
        if (null === self::$reservedMemory) {
            self::$reservedMemory = str_repeat('x', 10240);
            register_shutdown_function(__CLASS__.'::handleFatalError');
        }

        if ($handlerIsNew = null === $handler) {
            $handler = new static();
        }

        if (null === $prev = set_error_handler([$handler, 'handleError'])) {
            restore_error_handler();
            // Specifying the error types earlier would expose us to https://bugs.php.net/63206
            set_error_handler([$handler, 'handleError'], $handler->thrownErrors | $handler->loggedErrors);
            $handler->isRoot = true;
        }

        if ($handlerIsNew && \is_array($prev) && $prev[0] instanceof self) {
            $handler = $prev[0];
            $replace = false;
        }
        if (!$replace && $prev) {
            restore_error_handler();
            $handlerIsRegistered = \is_array($prev) && $handler === $prev[0];
        } else {
            $handlerIsRegistered = true;
        }
        if (\is_array($prev = set_exception_handler([$handler, 'handleException'])) && $prev[0] instanceof self) {
            restore_exception_handler();
            if (!$handlerIsRegistered) {
                $handler = $prev[0];
            } elseif ($handler !== $prev[0] && $replace) {
                set_exception_handler([$handler, 'handleException']);
                $p = $prev[0]->setExceptionHandler(null);
                $handler->setExceptionHandler($p);
                $prev[0]->setExceptionHandler($p);
            }
        } else {
            $handler->setExceptionHandler($prev);
        }

        $handler->throwAt(\E_ALL & $handler->thrownErrors, true);

        return $handler;
    }

    public function __construct(BufferingLogger $bootstrappingLogger = null)
    {
        if ($bootstrappingLogger) {
            $this->bootstrappingLogger = $bootstrappingLogger;
            $this->setDefaultLogger($bootstrappingLogger);
        }
        $this->traceReflector = new \ReflectionProperty('Exception', 'trace');
        $this->traceReflector->setAccessible(true);
    }

    /**
     * Sets a logger to non assigned errors levels.
     *
     * @param LoggerInterface $logger  A PSR-3 logger to put as default for the given levels
     * @param array|int       $levels  An array map of E_* to LogLevel::* or an integer bit field of E_* constants
     * @param bool            $replace Whether to replace or not any existing logger
     */
    public function setDefaultLogger(LoggerInterface $logger, $levels = \E_ALL, $replace = false)
    {
        $loggers = [];

        if (\is_array($levels)) {
            foreach ($levels as $type => $logLevel) {
                if (empty($this->loggers[$type][0]) || $replace || $this->loggers[$type][0] === $this->bootstrappingLogger) {
                    $loggers[$type] = [$logger, $logLevel];
                }
            }
        } else {
            if (null === $levels) {
                $levels = \E_ALL;
            }
            foreach ($this->loggers as $type => $log) {
                if (($type & $levels) && (empty($log[0]) || $replace || $log[0] === $this->bootstrappingLogger)) {
                    $log[0] = $logger;
                    $loggers[$type] = $log;
                }
            }
        }

        $this->setLoggers($loggers);
    }

    /**
     * Sets a logger for each error level.
     *
     * @param array $loggers Error levels to [LoggerInterface|null, LogLevel::*] map
     *
     * @return array The previous map
     *
     * @throws \InvalidArgumentException
     */
    public function setLoggers(array $loggers)
    {
        $prevLogged = $this->loggedErrors;
        $prev = $this->loggers;
        $flush = [];

        foreach ($loggers as $type => $log) {
            if (!isset($prev[$type])) {
                throw new \InvalidArgumentException('Unknown error type: '.$type);
            }
            if (!\is_array($log)) {
                $log = [$log];
            } elseif (!\array_key_exists(0, $log)) {
                throw new \InvalidArgumentException('No logger provided.');
            }
            if (null === $log[0]) {
                $this->loggedErrors &= ~$type;
            } elseif ($log[0] instanceof LoggerInterface) {
                $this->loggedErrors |= $type;
            } else {
                throw new \InvalidArgumentException('Invalid logger provided.');
            }
            $this->loggers[$type] = $log + $prev[$type];

            if ($this->bootstrappingLogger && $prev[$type][0] === $this->bootstrappingLogger) {
                $flush[$type] = $type;
            }
        }
        $this->reRegister($prevLogged | $this->thrownErrors);

        if ($flush) {
            foreach ($this->bootstrappingLogger->cleanLogs() as $log) {
                $type = $log[2]['exception'] instanceof \ErrorException ? $log[2]['exception']->getSeverity() : \E_ERROR;
                if (!isset($flush[$type])) {
                    $this->bootstrappingLogger->log($log[0], $log[1], $log[2]);
                } elseif ($this->loggers[$type][0]) {
                    $this->loggers[$type][0]->log($this->loggers[$type][1], $log[1], $log[2]);
                }
            }
        }

        return $prev;
    }

    /**
     * Sets a user exception handler.
     *
     * @param callable $handler A handler that will be called on Exception
     *
     * @return callable|null The previous exception handler
     */
    public function setExceptionHandler(callable $handler = null)
    {
        $prev = $this->exceptionHandler;
        $this->exceptionHandler = $handler;

        return $prev;
    }

    /**
     * Sets the PHP error levels that throw an exception when a PHP error occurs.
     *
     * @param int  $levels  A bit field of E_* constants for thrown errors
     * @param bool $replace Replace or amend the previous value
     *
     * @return int The previous value
     */
    public function throwAt($levels, $replace = false)
    {
        $prev = $this->thrownErrors;
        $this->thrownErrors = ($levels | \E_RECOVERABLE_ERROR | \E_USER_ERROR) & ~\E_USER_DEPRECATED & ~\E_DEPRECATED;
        if (!$replace) {
            $this->thrownErrors |= $prev;
        }
        $this->reRegister($prev | $this->loggedErrors);

        return $prev;
    }

    /**
     * Sets the PHP error levels for which local variables are preserved.
     *
     * @param int  $levels  A bit field of E_* constants for scoped errors
     * @param bool $replace Replace or amend the previous value
     *
     * @return int The previous value
     */
    public function scopeAt($levels, $replace = false)
    {
        $prev = $this->scopedErrors;
        $this->scopedErrors = (int) $levels;
        if (!$replace) {
            $this->scopedErrors |= $prev;
        }

        return $prev;
    }

    /**
     * Sets the PHP error levels for which the stack trace is preserved.
     *
     * @param int  $levels  A bit field of E_* constants for traced errors
     * @param bool $replace Replace or amend the previous value
     *
     * @return int The previous value
     */
    public function traceAt($levels, $replace = false)
    {
        $prev = $this->tracedErrors;
        $this->tracedErrors = (int) $levels;
        if (!$replace) {
            $this->tracedErrors |= $prev;
        }

        return $prev;
    }

    /**
     * Sets the error levels where the @-operator is ignored.
     *
     * @param int  $levels  A bit field of E_* constants for screamed errors
     * @param bool $replace Replace or amend the previous value
     *
     * @return int The previous value
     */
    public function screamAt($levels, $replace = false)
    {
        $prev = $this->screamedErrors;
        $this->screamedErrors = (int) $levels;
        if (!$replace) {
            $this->screamedErrors |= $prev;
        }

        return $prev;
    }

    /**
     * Re-registers as a PHP error handler if levels changed.
     */
    private function reRegister($prev)
    {
        if ($prev !== $this->thrownErrors | $this->loggedErrors) {
            $handler = set_error_handler('var_dump');
            $handler = \is_array($handler) ? $handler[0] : null;
            restore_error_handler();
            if ($handler === $this) {
                restore_error_handler();
                if ($this->isRoot) {
                    set_error_handler([$this, 'handleError'], $this->thrownErrors | $this->loggedErrors);
                } else {
                    set_error_handler([$this, 'handleError']);
                }
            }
        }
    }

    /**
     * Handles errors by filtering then logging them according to the configured bit fields.
     *
     * @param int    $type    One of the E_* constants
     * @param string $message
     * @param string $file
     * @param int    $line
     *
     * @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)
    {
        if (\PHP_VERSION_ID >= 70300 && \E_WARNING === $type && '"' === $message[0] && false !== strpos($message, '" targeting switch is equivalent to "break')) {
            $type = \E_DEPRECATED;
        }

        // Level is the current error reporting level to manage silent error.
        $level = error_reporting();
        $silenced = 0 === ($level & $type);
        // Strong errors are not authorized to be silenced.
        $level |= \E_RECOVERABLE_ERROR | \E_USER_ERROR | \E_DEPRECATED | \E_USER_DEPRECATED;
        $log = $this->loggedErrors & $type;
        $throw = $this->thrownErrors & $type & $level;
        $type &= $level | $this->screamedErrors;

        if (!$type || (!$log && !$throw)) {
            return !$silenced && $type && $log;
        }
        $scope = $this->scopedErrors & $type;

        if (4 < $numArgs = \func_num_args()) {
            $context = func_get_arg(4) ?: [];
            $backtrace = 5 < $numArgs ? func_get_arg(5) : null; // defined on HHVM
        } else {
            $context = [];
            $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;
        }

        if (null !== $backtrace && $type & \E_ERROR) {
            // E_ERROR fatal errors are triggered on HHVM when
            // hhvm.error_handling.call_user_handler_on_fatals=1
            // which is the way to get their backtrace.
            $this->handleFatalError(compact('type', 'message', 'file', 'line', 'backtrace'));

            return true;
        }

        $logMessage = $this->levels[$type].': '.$message;

        if (null !== self::$toStringException) {
            $errorAsException = self::$toStringException;
            self::$toStringException = null;
        } elseif (!$throw && !($type & $level)) {
            if (!isset(self::$silencedErrorCache[$id = $file.':'.$line])) {
                $lightTrace = $this->tracedErrors & $type ? $this->cleanTrace(debug_backtrace(\DEBUG_BACKTRACE_IGNORE_ARGS, 3), $type, $file, $line, false) : [];
                $errorAsException = new SilencedErrorContext($type, $file, $line, $lightTrace);
            } elseif (isset(self::$silencedErrorCache[$id][$message])) {
                $lightTrace = null;
                $errorAsException = self::$silencedErrorCache[$id][$message];
                ++$errorAsException->count;
            } else {
                $lightTrace = [];
                $errorAsException = null;
            }

            if (100 < ++self::$silencedErrorCount) {
                self::$silencedErrorCache = $lightTrace = [];
                self::$silencedErrorCount = 1;
            }
            if ($errorAsException) {
                self::$silencedErrorCache[$id][$message] = $errorAsException;
            }
            if (null === $lightTrace) {
                return true;
            }
        } else {
            if ($scope) {
                $errorAsException = new ContextErrorException($logMessage, 0, $type, $file, $line, $context);
            } else {
                $errorAsException = new \ErrorException($logMessage, 0, $type, $file, $line);
            }

            // Clean the trace by removing function arguments and the first frames added by the error handler itself.
            if ($throw || $this->tracedErrors & $type) {
                $backtrace = $backtrace ?: $errorAsException->getTrace();
                $lightTrace = $this->cleanTrace($backtrace, $type, $file, $line, $throw);
                $this->traceReflector->setValue($errorAsException, $lightTrace);
            } else {
                $this->traceReflector->setValue($errorAsException, []);
            }
        }

        if ($throw) {
            if (\PHP_VERSION_ID < 70400 && \E_USER_ERROR & $type) {
                for ($i = 1; isset($backtrace[$i]); ++$i) {
                    if (isset($backtrace[$i]['function'], $backtrace[$i]['type'], $backtrace[$i - 1]['function'])
                        && '__toString' === $backtrace[$i]['function']
                        && '->' === $backtrace[$i]['type']
                        && !isset($backtrace[$i - 1]['class'])
                        && ('trigger_error' === $backtrace[$i - 1]['function'] || 'user_error' === $backtrace[$i - 1]['function'])
                    ) {
                        // Here, we know trigger_error() has been called from __toString().
                        // HHVM is fine with throwing from __toString() but PHP triggers a fatal error instead.
                        // A small convention allows working around the limitation:
                        // given a caught $e exception in __toString(), quitting the method with
                        // `return trigger_error($e, E_USER_ERROR);` allows this error handler
                        // to make $e get through the __toString() barrier.

                        foreach ($context as $e) {
                            if (($e instanceof \Exception || $e instanceof \Throwable) && $e->__toString() === $message) {
                                if (1 === $i) {
                                    // On HHVM
                                    $errorAsException = $e;
                                    break;
                                }
                                self::$toStringException = $e;

                                return true;
                            }
                        }

                        if (1 < $i) {
                            // On PHP (not on HHVM), display the original error message instead of the default one.
                            $this->handleException($errorAsException);

                            // Stop the process by giving back the error to the native handler.
                            return false;
                        }
                    }
                }
            }

            throw $errorAsException;
        }

        if ($this->isRecursive) {
            $log = 0;
        } elseif (self::$stackedErrorLevels) {
            self::$stackedErrors[] = [
                $this->loggers[$type][0],
                ($type & $level) ? $this->loggers[$type][1] : LogLevel::DEBUG,
                $logMessage,
                $errorAsException ? ['exception' => $errorAsException] : [],
            ];
        } else {
            if (\PHP_VERSION_ID < (\PHP_VERSION_ID < 70400 ? 70316 : 70404) && !\defined('HHVM_VERSION')) {
                $currentErrorHandler = set_error_handler('var_dump');
                restore_error_handler();
            }

            try {
                $this->isRecursive = true;
                $level = ($type & $level) ? $this->loggers[$type][1] : LogLevel::DEBUG;
                $this->loggers[$type][0]->log($level, $logMessage, $errorAsException ? ['exception' => $errorAsException] : []);
            } finally {
                $this->isRecursive = false;

                if (\PHP_VERSION_ID < (\PHP_VERSION_ID < 70400 ? 70316 : 70404) && !\defined('HHVM_VERSION')) {
                    set_error_handler($currentErrorHandler);
                }
            }
        }

        return !$silenced && $type && $log;
    }

    /**
     * Handles an exception by logging then forwarding it to another handler.
     *
     * @param \Exception|\Throwable $exception An exception to handle
     * @param array                 $error     An array as returned by error_get_last()
     *
     * @internal
     */
    public function handleException($exception, array $error = null)
    {
        if (null === $error) {
            self::$exitCode = 255;
        }
        if (!$exception instanceof \Exception) {
            $exception = new FatalThrowableError($exception);
        }
        $type = $exception instanceof FatalErrorException ? $exception->getSeverity() : \E_ERROR;
        $handlerException = null;

        if (($this->loggedErrors & $type) || $exception instanceof FatalThrowableError) {
            if ($exception instanceof FatalErrorException) {
                if ($exception instanceof FatalThrowableError) {
                    $error = [
                        'type' => $type,
                        'message' => $message = $exception->getMessage(),
                        'file' => $exception->getFile(),
                        'line' => $exception->getLine(),
                    ];
                } else {
                    $message = 'Fatal '.$exception->getMessage();
                }
            } elseif ($exception instanceof \ErrorException) {
                $message = 'Uncaught '.$exception->getMessage();
            } else {
                $message = 'Uncaught Exception: '.$exception->getMessage();
            }
        }
        if ($this->loggedErrors & $type) {
            try {
                $this->loggers[$type][0]->log($this->loggers[$type][1], $message, ['exception' => $exception]);
            } catch (\Exception $handlerException) {
            } catch (\Throwable $handlerException) {
            }
        }
        if ($exception instanceof FatalErrorException && !$exception instanceof OutOfMemoryException && $error) {
            foreach ($this->getFatalErrorHandlers() as $handler) {
                if ($e = $handler->handleError($error, $exception)) {
                    $exception = $e;
                    break;
                }
            }
        }
        $exceptionHandler = $this->exceptionHandler;
        $this->exceptionHandler = null;
        try {
            if (null !== $exceptionHandler) {
                $exceptionHandler($exception);

                return;
            }
            $handlerException = $handlerException ?: $exception;
        } catch (\Exception $handlerException) {
        } catch (\Throwable $handlerException) {
        }
        if ($exception === $handlerException) {
            self::$reservedMemory = null; // Disable the fatal error handler
            throw $exception; // Give back $exception to the native handler
        }
        $this->handleException($handlerException);
    }

    /**
     * Shutdown registered function for handling PHP fatal errors.
     *
     * @param array $error An array as returned by error_get_last()
     *
     * @internal
     */
    public static function handleFatalError(array $error = null)
    {
        if (null === self::$reservedMemory) {
            return;
        }

        $handler = self::$reservedMemory = null;
        $handlers = [];
        $previousHandler = null;
        $sameHandlerLimit = 10;

        while (!\is_array($handler) || !$handler[0] instanceof self) {
            $handler = set_exception_handler('var_dump');
            restore_exception_handler();

            if (!$handler) {
                break;
            }
            restore_exception_handler();

            if ($handler !== $previousHandler) {
                array_unshift($handlers, $handler);
                $previousHandler = $handler;
            } elseif (0 === --$sameHandlerLimit) {
                $handler = null;
                break;
            }
        }
        foreach ($handlers as $h) {
            set_exception_handler($h);
        }
        if (!$handler) {
            return;
        }
        if ($handler !== $h) {
            $handler[0]->setExceptionHandler($h);
        }
        $handler = $handler[0];
        $handlers = [];

        if ($exit = null === $error) {
            $error = error_get_last();
        }

        try {
            while (self::$stackedErrorLevels) {
                static::unstackErrors();
            }
        } catch (\Exception $exception) {
            // Handled below
        } catch (\Throwable $exception) {
            // Handled below
        }

        if ($error && $error['type'] &= \E_PARSE | \E_ERROR | \E_CORE_ERROR | \E_COMPILE_ERROR) {
            // Let's not throw anymore but keep logging
            $handler->throwAt(0, true);
            $trace = isset($error['backtrace']) ? $error['backtrace'] : null;

            if (0 === strpos($error['message'], 'Allowed memory') || 0 === strpos($error['message'], 'Out of memory')) {
                $exception = new OutOfMemoryException($handler->levels[$error['type']].': '.$error['message'], 0, $error['type'], $error['file'], $error['line'], 2, false, $trace);
            } else {
                $exception = new FatalErrorException($handler->levels[$error['type']].': '.$error['message'], 0, $error['type'], $error['file'], $error['line'], 2, true, $trace);
            }
        }

        try {
            if (isset($exception)) {
                self::$exitCode = 255;
                $handler->handleException($exception, $error);
            }
        } catch (FatalErrorException $e) {
            // Ignore this re-throw
        }

        if ($exit && self::$exitCode) {
            $exitCode = self::$exitCode;
            register_shutdown_function('register_shutdown_function', function () use ($exitCode) { exit($exitCode); });
        }
    }

    /**
     * Configures the error handler for delayed handling.
     * Ensures also that non-catchable fatal errors are never silenced.
     *
     * As shown by http://bugs.php.net/42098 and http://bugs.php.net/60724
     * PHP has a compile stage where it behaves unusually. To workaround it,
     * we plug an error handler that only stacks errors for later.
     *
     * The most important feature of this is to prevent
     * autoloading until unstackErrors() is called.
     *
     * @deprecated since version 3.4, to be removed in 4.0.
     */
    public static function stackErrors()
    {
        @trigger_error('Support for stacking errors is deprecated since Symfony 3.4 and will be removed in 4.0.', \E_USER_DEPRECATED);

        self::$stackedErrorLevels[] = error_reporting(error_reporting() | \E_PARSE | \E_ERROR | \E_CORE_ERROR | \E_COMPILE_ERROR);
    }

    /**
     * Unstacks stacked errors and forwards to the logger.
     *
     * @deprecated since version 3.4, to be removed in 4.0.
     */
    public static function unstackErrors()
    {
        @trigger_error('Support for unstacking errors is deprecated since Symfony 3.4 and will be removed in 4.0.', \E_USER_DEPRECATED);

        $level = array_pop(self::$stackedErrorLevels);

        if (null !== $level) {
            $errorReportingLevel = error_reporting($level);
            if ($errorReportingLevel !== ($level | \E_PARSE | \E_ERROR | \E_CORE_ERROR | \E_COMPILE_ERROR)) {
                // If the user changed the error level, do not overwrite it
                error_reporting($errorReportingLevel);
            }
        }

        if (empty(self::$stackedErrorLevels)) {
            $errors = self::$stackedErrors;
            self::$stackedErrors = [];

            foreach ($errors as $error) {
                $error[0]->log($error[1], $error[2], $error[3]);
            }
        }
    }

    /**
     * Gets the fatal error handlers.
     *
     * Override this method if you want to define more fatal error handlers.
     *
     * @return FatalErrorHandlerInterface[] An array of FatalErrorHandlerInterface
     */
    protected function getFatalErrorHandlers()
    {
        return [
            new UndefinedFunctionFatalErrorHandler(),
            new UndefinedMethodFatalErrorHandler(),
            new ClassNotFoundFatalErrorHandler(),
        ];
    }

    private function cleanTrace($backtrace, $type, $file, $line, $throw)
    {
        $lightTrace = $backtrace;

        for ($i = 0; isset($backtrace[$i]); ++$i) {
            if (isset($backtrace[$i]['file'], $backtrace[$i]['line']) && $backtrace[$i]['line'] === $line && $backtrace[$i]['file'] === $file) {
                $lightTrace = \array_slice($lightTrace, 1 + $i);
                break;
            }
        }
        if (!($throw || $this->scopedErrors & $type)) {
            for ($i = 0; isset($lightTrace[$i]); ++$i) {
                unset($lightTrace[$i]['args'], $lightTrace[$i]['object']);
            }
        }

        return $lightTrace;
    }
}
Name	Size	Permission
Exception	---	0755
FatalErrorHandler	---	0755
Resources	---	0755
Tests	---	0755
BufferingLogger.php	732 bytes	0644
Debug.php	1766 bytes	0644
DebugClassLoader.php	16502 bytes	0644
ErrorHandler.php	30042 bytes	0644
ExceptionHandler.php	24890 bytes	0644
LICENSE	1065 bytes	0644
README.md	541 bytes	0644
composer.json	873 bytes	0644
phpunit.xml.dist	988 bytes	0644
File Content: ErrorHandler.php

File Content: `ErrorHandler.php`
