Unset block instance's variations field

src/wp-includes/blocks.php

@@ -544,6 +544,10 @@ function register_block_type_from_metadata( $file_or_folder, $args = array() ) {
 				$variations = require $variations_path;
 				return $variations;
 			};
+			// The block instance's `variations` field is only allowed to be an array
+			// (of known block variations). We unset it so that the block instance will
+			// provide a getter that returns the result of the `variation_callback` instead.
+			unset( $settings['variations'] );
 		}
 	}
 

tests/phpunit/tests/blocks/register.php

@@ -977,15 +977,15 @@ public function test_register_block_type_from_metadata_with_variations_php_file(
 		remove_filter( 'block_type_metadata', $filter_metadata_registration );
 
 		$this->assertInstanceOf( 'WP_Block_Type', $result, 'The block was not registered' );
-		$this->assertSame( 'variations.php', $result->variations, 'The block variations are incorrect' );
-		$this->assertIsCallable( $result->variation_callback, 'The variation callback hasn\'t been set' );
 
+		$this->assertIsCallable( $result->variation_callback, 'The variation callback hasn\'t been set' );
 		$expected_variations = require DIR_TESTDATA . '/blocks/notice/variations.php';
 		$this->assertSame(
 			$expected_variations,
 			call_user_func( $result->variation_callback ),
 			'The variation callback hasn\'t been set correctly'
 		);
+		$this->assertSame( $expected_variations, $result->variations, 'The block variations are incorrect' );
 	}
 
 	/**