Empty template rendering as NULL

[j6s]

Description

This is only a minor thing that I noticed - it may even be happening on purpose:
When rendering an empty template NULL is being returned instead of an empty string (which I would have expected).

I noticed this when starting to mock up empty files as templates while using strict_types=1.

[Description of the bug or feature]

Test to outline issue

$view = new StandaloneView();
$view->setTemplateSource('');

$this->assertNotNull($view->render());
// => Failed asserting that null is not null.

Affected Versions

I have not tried to find out how far back this issue goes - all I can say is that it affects the most current versions (Neos 4.3).

Neos: 4.3.x-dev 3b49cca
Flow: 5.3.2

[albe]

That's indeed an issue with TYPO3 Fluid then, because we don't override the render function anywhere and setTemplateSource() just forwards to the internals of Fluid. On a quick glance I couldn't find anything obvious in the Fluid source, in the case above the result should be a single TextNode with an empty string content and hence the render method should evaluate to that empty string instead of null, but obviously there's something else going on. A quick unit test could help verify the illbehaviour.