Filter custom block templates with PHP

This method calls get_block_templates once and uses block template properties
directly for filtering. This way, we can avoid hitting the database for each
public post type.

The previous method is useful when we already know the current post type we
request templates for, like when using REST API.

Follows [52334].
See #54335.
Props mamaduka, youknowriad.


git-svn-id: https://develop.svn.wordpress.org/trunk@52365 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-theme.php

@@ -1250,9 +1250,17 @@ public function get_post_templates() {
 			}
 
 			if ( current_theme_supports( 'block-templates' ) ) {
+				$block_templates = get_block_templates( array(), 'wp_template' );
 				foreach ( get_post_types( array( 'public' => true ) ) as $type ) {
-					$block_templates = get_block_templates( array( 'post_type' => $type ), 'wp_template' );
 					foreach ( $block_templates as $block_template ) {
+						if ( ! $block_template->is_custom ) {
+							continue;
+						}
+
+						if ( isset( $block_template->post_types ) && ! in_array( $type, $block_template->post_types, true ) ) {
+							continue;
+						}
+
 						$post_templates[ $type ][ $block_template->slug ] = $block_template->title;
 					}
 				}