Modifies the resolve_pattern_blocks function to include metadata for single-root patterns, allowing the pattern name and title to be stored in the block attributes.

Adds unit tests.

Author: ramonjd

src/wp-includes/blocks.php

@@ -1880,7 +1880,16 @@ function resolve_pattern_blocks( $blocks ) {
 				continue;
 			}
 
-			$blocks_to_insert   = parse_blocks( $pattern['content'] );
+			$blocks_to_insert = parse_blocks( trim( $pattern['content'] ) );
+
+			// For single-root patterns, add the pattern name to make this a pattern instance in the editor.
+			if ( count( $blocks_to_insert ) === 1 ) {
+				$blocks_to_insert[0]['attrs']['metadata'] = array(
+					'patternName' => $slug,
+					'name'        => $pattern['title'],
+				);
+			}
+
 			$seen_refs[ $slug ] = true;
 			$prev_inner_content = $inner_content;
 			$inner_content      = null;

tests/phpunit/tests/blocks/resolvePatternBlocks.php

@@ -30,12 +30,37 @@ public function set_up() {
 				'description' => 'Recursive pattern.',
 			)
 		);
+		register_block_pattern(
+			'core/single-root',
+			array(
+				'title'       => 'Single Root Pattern',
+				'content'     => '<!-- wp:paragraph -->Single root content<!-- /wp:paragraph -->',
+				'description' => 'A single root pattern.',
+			)
+		);
+		register_block_pattern(
+			'core/with-attrs',
+			array(
+				'title'       => 'Pattern With Attrs',
+				'content'     => '<!-- wp:paragraph {"className":"custom-class"} -->Content<!-- /wp:paragraph -->',
+				'description' => 'A pattern with existing attributes.',
+			)
+		);
+		register_block_pattern(
+			'core/nested-single',
+			array(
+				'title'       => 'Nested Pattern',
+				'content'     => '<!-- wp:group --><!-- wp:paragraph -->Nested content<!-- /wp:paragraph --><!-- wp:pattern {"slug":"core/single-root"} /--><!-- /wp:group -->',
+				'description' => 'A nested single root pattern.',
+			)
+		);
 	}
 
 	public function tear_down() {
 		unregister_block_pattern( 'core/test' );
 		unregister_block_pattern( 'core/recursive' );
-
+		unregister_block_pattern( 'core/single-root' );
+		unregister_block_pattern( 'core/with-attrs' );
 		parent::tear_down();
 	}
 
@@ -67,6 +92,12 @@ public function data_should_resolve_pattern_blocks_as_expected() {
 			'recursive pattern'              => array( '<!-- wp:pattern {"slug":"core/recursive"} /-->', '<!-- wp:paragraph -->Recursive<!-- /wp:paragraph -->' ),
 			// Resolves the pattern within a block.
 			'pattern within a block'         => array( '<!-- wp:group --><!-- wp:paragraph -->Before<!-- /wp:paragraph --><!-- wp:pattern {"slug":"core/test"} /--><!-- wp:paragraph -->After<!-- /wp:paragraph --><!-- /wp:group -->', '<!-- wp:group --><!-- wp:paragraph -->Before<!-- /wp:paragraph --><!-- wp:paragraph -->Hello<!-- /wp:paragraph --><!-- wp:paragraph -->World<!-- /wp:paragraph --><!-- wp:paragraph -->After<!-- /wp:paragraph --><!-- /wp:group -->' ),
+			// Resolves the single-root pattern and adds metadata.
+			'single-root pattern'            => array( '<!-- wp:pattern {"slug":"core/single-root"} /-->', '<!-- wp:paragraph {"metadata":{"patternName":"core/single-root","name":"Single Root Pattern"}} -->Single root content<!-- /wp:paragraph -->' ),
+			// Existing attributes are preserved when adding metadata.
+			'existing attributes preserved'  => array( '<!-- wp:pattern {"slug":"core/with-attrs"} /-->', '<!-- wp:paragraph {"className":"custom-class","metadata":{"patternName":"core/with-attrs","name":"Pattern With Attrs"}} -->Content<!-- /wp:paragraph -->' ),
+			// Resolves the nested single-root pattern and adds metadata.
+			'nested single-root pattern'     => array( '<!-- wp:pattern {"slug":"core/nested-single"} /-->', '<!-- wp:group {"metadata":{"patternName":"core/nested-single","name":"Nested Pattern"}} --><!-- wp:paragraph -->Nested content<!-- /wp:paragraph --><!-- wp:paragraph {"metadata":{"patternName":"core/single-root","name":"Single Root Pattern"}} -->Single root content<!-- /wp:paragraph --><!-- /wp:group -->' ),
 		);
 	}
 }