BUG: v:try render() vs. renderStatic()

[kitzberger]

I have checked that the bug exists in the dev-development branch
Yes

I have checked that there are no already open issues or recently closed issues about this bug
Yes

Describe the bug

The viewhelper v:try behaves differently when cached than when uncached.

The docs on this viewhelper indicates that f:then is optional, but it seems to me like it's not.

To Reproduce

	<v:try>
		<f:then>THEN_1</f:then>
		<f:else>ELSE_1</f:else>
	</v:try>
	<v:try>
		THEN_2
		<f:else>ELSE_2</f:else>
	</v:try>

Expected behavior

Always:

THEN_1 THEN_2

Actual behavior

Uncached	Cached
THEN_1 ELSE_1 THEN_2 ELSE_2	THEN_1 ELSE_2
Both blocks of both examples are being rendered! That's broken.	THEN_1 is correct. ELSE_2 isn't though!

It's two problems I reckon:

• For uncached calls: TryViewHelper->render() calls renderChildren() instead of renderThenChild(), so both blocks are being rendered.
• For cached calls: TryViewHelper::renderStatic() tries to access $arguments['__then']() without "isset" beforehand (which triggers an Exception due to a PHP 8 warning, which will then render the "else part".

Additional context

• PHP 8.1
• TYPO3 11.5
• EXT:vhs 7.1.0