Available block context does not flow to blocks inside the Post Template block

[helgatheviking]

Description

I was trying to provide some context from the Query block down to the Post Title block (or any block inside the Post Template) and modified the suggestion described here.

But my custom context key was never available.

I tracked this down for a while and ultimately I think it is because of how the post template block is dynamically rendered. Specifically, it doesn't pass a 2nd parameter when instantiating the new WP_Block() for each post in the query's loop. So then in the WP_Block class there's no available context to look at when setting the new block's context.

Apologies if this should be reported to core somewhere.

At a minimum, if

$block_content = ( new WP_Block( $block_instance ) )->render( array( 'dynamic' => false ) );

Is changed to

$block_content = ( new WP_Block( $block_instance, $block-context ) )->render( array( 'dynamic' => false ) );

Then any context on the post template block will be available for consumption on the post title and other nested blocks.

Step-by-step reproduction instructions

1. Activate below code snippet
2. Insert a query block anywhere and save.
3. view on front end. Each post title should be prefixed by "no tacos" (a very sad state, indeed)

Screenshots, screen recording, code snippet

add_filter( 'render_block_context', function( $context, $parsed_block ) {
	if ( 'core/query' === $parsed_block['blockName'] ) {
		$context['taco'] = 'we love tacos';
	}
	return $context;
}, 10, 2 );

add_filter( 'block_type_metadata',  function( $metadata ) {

	if ( ! isset( $metadata['name'] ) ) {
		return $metadata;
	}
	
	if ( 'core/query' === $metadata['name'] ) {
		$metadata['providesContext']            ??= [];
		$metadata['providesContext']['taco']    = 'taco';
	}

	if ( 'core/post-template' === $metadata['name'] ) { // Ideally, I shouldn't need this either.
		$metadata['usesContext']   ??= [];
		$metadata['usesContext'][] = 'taco';
	}

	if ( 'core/post-title' === $metadata['name'] ) {
		$metadata['usesContext']   ??= [];
		$metadata['usesContext'][] = 'taco';
	}

	return $metadata;
} );


add_action( 'render_block_core/post-title', function( $block_content, $block, $instance ) {
    
	if ( ! isset( $instance->context ) ) {
        return $block_content;
    }

    $context = $instance->context;
    $taco    = $context['taco']    ??= 'no tacos';

    return $taco . ' ' . $block_content;

}, 10, 3 );

Environment info

WP 6.7.1
Twenty Twenty four

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

• Yes

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure