Syntax Error for nullable return type with PHP 7.1 and Flow 4.0.2

I am writing a Flow application using PHP 7.1.0. In one of my domain models (postalAddress) I have a property named “postbox” for entering the postbox number of a users postal address.

The corresponding setter method looks like this:

 * @return string
 public function getPostBox(): string
     return $this->postBox;

With the return type string this method MUST return a valid string (empty strings are allowed), even if the user has no postbox. With PHP 7.1 nullable return types may be defined by preceding the return type with a question mark:

 * @return string
 public function getPostBox(): ?string
     return $this->postBox;

When I create an instance of this entity type in a commandcontroller command, I get this syntax error:

syntax error, unexpected ‘?’

For testing purposes I created a simple test.php file in my localhost directory. In this file I wrote a single function for testing the return type definition. Both variants (with and without “?”) for string return types worked perfectly fine in browser and on command line as well.

==> Seems to be, this is a flow problem, isn’t it?

I’ll attach you guys the complete error log below:

Exception #1355480641 in line 321 of /Applications/MAMP/htdocs/volleymanager.local/Packages/Framework/Neos.Flow/Classes/Core/Booting/Scripts.php: syntax error, unexpected ‘?’

Type: ParseError
File: Packages/Application/SportManager.Core/Classes/Domain/Model/PostalAddress.p
Line: 90

13 Neos\Flow\Core\Booting\Scripts::executeCommand(“neos.flow:core:compile”, array|16|)
12 Neos\Flow\Core\Booting\Scripts::initializeProxyClasses(Neos\Flow\Core\Bootstrap)
11 call_user_func(array|2|, Neos\Flow\Core\Bootstrap)
10 Neos\Flow\Core\Booting\Step::__invoke(Neos\Flow\Core\Bootstrap)
9 Neos\Flow\Core\Booting\Sequence::invokeStep(Neos\Flow\Core\Booting\Step, Neos\Flow\Core\Bootstrap)
8 Neos\Flow\Core\Booting\Sequence::invokeStep(Neos\Flow\Core\Booting\Step, Neos\Flow\Core\Bootstrap)
7 Neos\Flow\Core\Booting\Sequence::invokeStep(Neos\Flow\Core\Booting\Step, Neos\Flow\Core\Bootstrap)
6 Neos\Flow\Core\Booting\Sequence::invokeStep(Neos\Flow\Core\Booting\Step, Neos\Flow\Core\Bootstrap)
5 Neos\Flow\Core\Booting\Sequence::invoke(Neos\Flow\Core\Bootstrap)
4 Neos\Flow\Cli\CommandRequestHandler::boot(“Runtime”)
3 Neos\Flow\Cli\CommandRequestHandler::handleRequest()
2 Neos\Flow\Core\Bootstrap::run()
1 require("/Applications/MAMP/htdocs/volleymanager.local/Packages/Framework/Neos.Flow/Scripts/flow.php")

Yes, we need to support that on our side. Would you copy/paste this into an issue over at That’d be most awesome!

Feel free to mention my GH user (kdambekalns) in the issue, I’ll have a look then.