Block Hooks API: Refactor Navigation to account for get_hooked_blocks_by_anchor_block

[tjcafferkey]

Related WordPress/wordpress-develop#6584

What?

Consolidated our approach to getting hooked blocks which means function signatures have changed for the visitor functions. So checking for the existence of get_hooked_blocks_by_anchor_block before using it.

Why?

Because the function signatures of the visitor functions have now changed.

How?

Use function_exists before executing code that depends on it.

Testing Instructions

Follow the below stops for WordPress 6.5/6.6 to ensure no regressions have been introduced, and then again using latest trunk of wordpress-develop once WordPress/wordpress-develop#6584 has been merged.

1. Add the below code to your themes functions.php
2. Load frontend and check the Login/Logout block is an inner block of the core Navigation block and hasn't been added twice.
3. Load the Header template part in the Site Editor and check that the Login/Logout block is present as an inner block of the core Navigation and hasn't been added twice.
4. Make customisations to move the block and check it persists between reloads.
5. Make customisations to remove the block completely and check it persists between reloads.
6. Remove the PHP code added in step 1, and now add the below JSON to the same blocks block.json file and retest starting from step 2.

function register_logout_block_as_navigation_last_child( $hooked_blocks, $position, $anchor_block, $context ) {
	if ( $anchor_block === 'core/navigation' && $position === 'last_child' ) {
		$hooked_blocks[] = 'core/loginout';
	}

	return $hooked_blocks;
}

add_filter( 'hooked_block_types', 'register_logout_block_as_navigation_last_child', 10, 4 );

"blockHooks": {
	"core/navigation": "lastChild"
}

[github-actions]

Flaky tests detected in 385d07b.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/9566832934
📝 Reported issues:

• [Flaky Test] Redirection after template creation #60678 in /test/e2e/specs/site-editor/site-editor-url-navigation.spec.js

[github-actions]

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Co-authored-by: tjcafferkey <tomjcafferkey@git.wordpress.org>

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