REST API: Prevent database error when deleting meta data.

peterwilsoncc · peterwilsoncc · commit 7e66aefa7ff0 · 2021-03-25T00:02:35.000Z
Add a check to `WP_REST_Meta_Fields::delete_meta_value()` ensuring meta data is set before attempting to delete it from the database. If the data does not exist, the delete is considered successful as the data matches the desired state. Props BrechtVds, goaroundagain, TimothyBlynJacobs. Merges [50567] to the 5.7 branch. Fixes #52787. git-svn-id: https://develop.svn.wordpress.org/branches/5.7@50573 602fd350-edb4-49c9-b593-d223f7449a82
diff --git a/src/wp-includes/rest-api/fields/class-wp-rest-meta-fields.php b/src/wp-includes/rest-api/fields/class-wp-rest-meta-fields.php
@@ -232,6 +232,10 @@ protected function delete_meta_value( $object_id, $meta_key, $name ) {
 			);
 		}
 
+		if ( null === get_metadata_raw( $meta_type, $object_id, wp_slash( $meta_key ) ) ) {
+			return true;
+		}
+
 		if ( ! delete_metadata( $meta_type, $object_id, wp_slash( $meta_key ) ) ) {
 			return new WP_Error(
 				'rest_meta_database_error',
diff --git a/tests/phpunit/tests/rest-api/rest-post-meta-fields.php b/tests/phpunit/tests/rest-api/rest-post-meta-fields.php
@@ -1052,6 +1052,42 @@ public function test_remove_multi_value_with_empty_array() {
 		$this->assertEmpty( $meta );
 	}
 
+	/**
+	 * Ensure deleting non-existant meta data behaves gracefully.
+	 *
+	 * @ticket 52787
+	 * @dataProvider data_delete_does_not_trigger_error_if_no_meta_values
+	 *
+	 * @param array|null $delete_value Value used to delete meta data.
+	 */
+	public function test_delete_does_not_trigger_error_if_no_meta_values( $delete_value ) {
+		$this->grant_write_permission();
+
+		$data    = array(
+			'meta' => array(
+				'test_multi' => $delete_value,
+			),
+		);
+		$request = new WP_REST_Request( 'POST', sprintf( '/wp/v2/posts/%d', self::$post_id ) );
+		$request->set_body_params( $data );
+
+		$response = rest_get_server()->dispatch( $request );
+
+		$this->assertSame( 200, $response->get_status() );
+	}
+
+	/**
+	 * Data provider for test_delete_does_not_trigger_error_if_no_meta_values().
+	 *
+	 * @return array[] Array of test parameters.
+	 */
+	public function data_delete_does_not_trigger_error_if_no_meta_values() {
+		return array(
+			array( array() ),
+			array( null ),
+		);
+	}
+
 	public function test_remove_multi_value_db_error() {
 		add_post_meta( self::$post_id, 'test_multi', 'val1' );
 		$values = get_post_meta( self::$post_id, 'test_multi', false );
