Block Hooks: Fix context in update_ignored_hooked_blocks_postmeta

[ockham]

Discovered while working on #7898.

Testing Instructions

Also see the screencasts further below.

Preparatory steps:

• Make sure you're using a Block Theme that uses a Navigation block in its home page template (e.g. in its header or footer). TT4 should work.
• Upload the following code as a new plugin (i.e. copy to a new PHP file, zip, and upload to your WP install).

<?php
/**
 * Plugin Name:       Add Login/out block to Header Navigation
 * Description:       Block Hooks API demonstration
 * Version:           0.1.0
 * Requires at least: 6.7
 */

function add_loginout_block_to_header_navigation( $hooked_block_types, $relative_position, $anchor_block_type, $context ) {

	// Is $context a Navigation menu?
	if ( ! $context instanceof WP_Post || 'wp_navigation' !== $context->post_type ) {
		return $hooked_block_types;
	}
	
	if ( 'last_child' === $relative_position && 'core/navigation' === $anchor_block_type ) {
		$hooked_block_types[] = 'core/loginout';
	}

	return $hooked_block_types;
}
add_filter( 'hooked_block_types', 'add_loginout_block_to_header_navigation', 10, 4 );

To verify the issue (on trunk):

• Activate the plugin.
• On the frontend, verify that a new "Log in" link has been added as the last item in your Navigation block.
• Click on "Edit site", and move that Login/out block to a different position within the Nav block.
• Save your changes, and view them on the frontend once again.
• Note that while the block is present in your chosen position, it is also still present as the Nav block's last child ❌
• Click on "Edit site" once again. The editor should now reflect what you just saw on the frontend.
• Deactivate the plugin.
• Reload the Site Editor. Only the instance of the Login/out block that you moved should still be present.
• Delete that instance, and save the template. View it on the frontend to verify that the Navigation block is now in its original state (i.e. no "Log in" links).

To verify the fix (on this branch):

• Switch to this branch.
• Re-activate the plugin.
• On the frontend, verify that a new "Log in" link has been added as the last item in your Navigation block.
• Click on "Edit site", and move that Login/out block to a different position within the Nav block.
• Save your changes, and view them on the frontend once again.
• Note that the block was successfully moved to your chosen position, and is no longer present in its previous place (as the Nav block's last child) ✅
• Click on "Edit site" once again. The editor should reflect what you just saw on the frontend (Login/out block in desired position).

Screencast

Before

After

Trac ticket: https://core.trac.wordpress.org/ticket/62639

---

This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

[github-actions]

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[github-actions]

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the props-bot label.

Core Committers: Use this line as a base for the props when committing in SVN:

Props bernhard-reiter.

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[ockham]

Committed to Core trunk in https://core.trac.wordpress.org/changeset/59482.

[cbravobernal]

LGTM!