It was debug difficult of an error occurred by after handle pipeline

[Moln]

Code to reproduce the issue

It was difficult for us to debug error/exception, when an error/exception occurred by after handle pipeline.

These are situations that may occur.

1. Output has been emitted previously.
   • When I have a config file and there is no declare(strict_types=1) and exists UTF8+BOM.
   • Echo something in middleware or handler.
   • etc..
2. Throw an errors/exceptions in ErrorHandler's listeners.
   • When I attach a logger listener, and logging error.
   • etc..

There will output an empty response (status 200). Then, we don't know what happened.

Expected results

Output messages by Whoops.

Actual results

Response OK (status code 200). And no error/exception outputed.

Suggestions

Remove $whoops->writeToOutput(false) in WhoopsFactory.

https://github.com/zendframework/zend-expressive/blob/491da1e365d54e467026641b5984c0dd181ebe90/src/Container/WhoopsFactory.php#L56

And add disable/enable send on both sides of get handleException result.

https://github.com/zendframework/zend-expressive/blob/491da1e365d54e467026641b5984c0dd181ebe90/src/Middleware/WhoopsErrorResponseGenerator.php#L82-L84

        $sendOutput = $this->whoops->writeToOutput();
        $this->whoops->writeToOutput(false);
        $response
            ->getBody()
            ->write($this->whoops->handleException($e));
        $this->whoops->writeToOutput($sendOutput); //Restore to write to output.

[weierophinney]

@Moln would you be willing to create a pull request based on your suggestion?

[Moln]

@weierophinney Yeah, I created.