Make any PHP Exception serializable by flattening complex values in backtrace.

flattenExceptionBacktrace.php

<?php
    function flattenExceptionBacktrace(\Throwable $exception) {
        if ($exception instanceof \Exception) {
            $traceProperty = (new \ReflectionClass('Exception'))->getProperty('trace');
        } else {
            $traceProperty = (new \ReflectionClass('Error'))->getProperty('trace');
        }
        $traceProperty->setAccessible(true);

        $flatten = function(&$value, $key) {
            if ($value instanceof \Closure) {
                $closureReflection = new \ReflectionFunction($value);
                $value = sprintf(
                    '(Closure at %s:%s)',
                    $closureReflection->getFileName(),
                    $closureReflection->getStartLine()
                );
            } elseif (is_object($value)) {
                $value = sprintf('object(%s)', get_class($value));
            } elseif (is_resource($value)) {
                $value = sprintf('resource(%s)', get_resource_type($value));
            }
        };

        $previousexception = $exception;
        do {
            if ($previousexception === NULL) {
                break;
            }
            $exception = $previousexception;
            $trace = $traceProperty->getValue($exception);
            foreach($trace as &$call) {
                array_walk_recursive($call['args'], $flatten);
            }
            $traceProperty->setValue($exception, $trace);
        } while($previousexception = $exception->getPrevious());

        $traceProperty->setAccessible(false);
    }