Lazy load variations for template parts.

src/wp-admin/includes/post.php

@@ -2302,7 +2302,6 @@
 		'ancestor'         => 'ancestor',
 		'keywords'         => 'keywords',
 		'example'          => 'example',
-		'variations'       => 'variations',
 	);
 
 	foreach ( $block_registry->get_all_registered() as $block_name => $block_type ) {
@@ -2317,6 +2316,7 @@
 
 			$blocks[ $block_name ][ $key ] = $block_type->{ $field };
 		}
+		$blocks[ $block_name ][ 'variations' ] = $block_type->get_variations();
 	}
 
 	return $blocks;

src/wp-includes/blocks/template-part.php

@@ -276,8 +276,9 @@ function register_block_core_template_part() {
 		__DIR__ . '/template-part',
 		array(
 			'render_callback' => 'render_block_core_template_part',
-			'variations'      => build_template_part_block_variations(),
 		)
 	);
 }
 add_action( 'init', 'register_block_core_template_part' );
+
+add_filter( 'get_variations_block_core/template-part', 'build_template_part_block_variations' );

src/wp-includes/class-wp-block-type.php

@@ -528,6 +528,25 @@ public function set_props( $args ) {
 		}
 	}
 
+	/**
+	 * Get all variations.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @return array Array of variations.
+	 */
+	public function get_variations() {
+		/**
+		 * Filters the arguments for registering a variations.
+		 *
+		 * @since 5.5.0
+		 *
+		 * @param array  $variations       Array of arguments for registering a block type.
+		 * @param string $block_type Block type name including namespace.
+		 */
+		return apply_filters( 'get_variations_block_' . $this->name, $this->variations, $this->name );
+	}
+
 	/**
 	 * Get all available block attributes including possible layout attribute from Columns block.
 	 *

src/wp-includes/rest-api/endpoints/class-wp-rest-block-types-controller.php

@@ -292,8 +292,7 @@
 				'view_script_handles',
 				'editor_style_handles',
 				'style_handles',
-				'variations',
-				'block_hooks',
+				'block_hooks'
 			),
 			$deprecated_fields
 		);
@@ -314,6 +313,11 @@
 			}
 		}
 
+		if ( rest_is_field_included( 'variations', $fields ) ) {
+			$field              = $block_type->get_variations();
+			$data['variations'] = rest_sanitize_value_from_schema( $field, $schema['properties']['variations'] );
+		}
+
 		if ( rest_is_field_included( 'styles', $fields ) ) {
 			$styles         = $this->style_registry->get_registered_styles_for_block( $block_type->name );
 			$styles         = array_values( $styles );

tests/phpunit/tests/blocks/register.php

@@ -807,7 +807,7 @@ public function test_block_registers_with_metadata_fixture() {
 					'keywords'    => array( 'failure' ),
 				),
 			),
-			$result->variations
+			$result->get_variations()
 		);
 		$this->assertSame(
 			array(
@@ -1030,7 +1030,7 @@ public function test_block_registers_with_metadata_i18n_support() {
 					'keywords'    => array( 'niepowodzenie' ),
 				),
 			),
-			$result->variations
+			$result->get_variations()
 		);
 	}