[WP 5.3] Declaration should be compatible with Walker::walk

[Chouby]

Bug Description

PHP 5.6 or above
WP 5.3-beta3
VIPCS 2.0

WP 5.3 modified the signature of Walker::walk(). If we adapt our code to this new signature, we get an error:

Declaration of `PLL_Walker_List::walk($elements, $max_depth, $args)` should be compatible with `Walker::walk($elements, $max_depth)`
(WordPressVIPMinimum.Classes.DeclarationCompatibility.DeclarationCompatibility)

The sniff should be adpated to the new method signature

Minimal Code Snippet

class PLL_Walker_List extends Walker {
	public function walk( $elements, $max_depth, ...$args ) {
		return parent::walk( $elements, $max_depth, $args );
	}
}

Tested Against master branch?

No but the code hasn't been modified for 5 months so cannot take this WP modification into account.

[GaryJones]

Thanks for reporting @Chouby!

Relevant lines: https://github.com/Automattic/VIP-Coding-Standards/blob/develop/WordPressVIPMinimum/Sniffs/Classes/DeclarationCompatibilitySniff.php#L148-L151

Changed signature in Walker:walk(): WordPress/WordPress@38a8513

[jrfnl]

@Chouby Just a little heads-up, your code sample is bug-prone.

The correct way to do it would be:

class PLL_Walker_List extends Walker {
	public function walk( $elements, $max_depth, ...$args ) {
		return parent::walk( $elements, $max_depth, ...$args );
	}
}

Note the argument unpacking in the return statement. If you pass $args to the parent without that, you are passing an array, not the individual arguments received.

[jrfnl]

Related: https://make.wordpress.org/core/2019/10/09/wp-5-3-introducing-the-spread-operator/

[Chouby]

@jrfnl Thank you! This indeed could have been a bug. I removed most of the original code where at some point $args = $args[0] to construct the minimal code snippet, when I should have built a new one to avoid making this mistake ;-)

[jrfnl]

@Chouby No worries, I just pointed it out in hopes of preventing the issue getting into a real codebase (or others finding this snippet and using it blindly).

[jrfnl]

@Chouby PR #505 should fix this. Testing appreciated.