WP_REST_Terms_Controller::update_item( WP_REST_Request $request )

	public function update_item( $request ) {
		$term = $this->get_term( $request['id'] );
		if ( is_wp_error( $term ) ) {
			return $term;
		}

		if ( isset( $request['parent'] ) ) {
			if ( ! is_taxonomy_hierarchical( $this->taxonomy ) ) {
				return new WP_Error( 'rest_taxonomy_not_hierarchical', __( 'Cannot set parent term, taxonomy is not hierarchical.' ), array( 'status' => 400 ) );
			}

			$parent = get_term( (int) $request['parent'], $this->taxonomy );

			if ( ! $parent ) {
				return new WP_Error( 'rest_term_invalid', __( 'Parent term does not exist.' ), array( 'status' => 400 ) );
			}
		}

		$prepared_term = $this->prepare_item_for_database( $request );

		// Only update the term if we haz something to update.
		if ( ! empty( $prepared_term ) ) {
			$update = wp_update_term( $term->term_id, $term->taxonomy, wp_slash( (array) $prepared_term ) );

			if ( is_wp_error( $update ) ) {
				return $update;
			}
		}

		$term = get_term( $term->term_id, $this->taxonomy );

		/** This action is documented in wp-includes/rest-api/endpoints/class-wp-rest-terms-controller.php */
		do_action( "rest_insert_{$this->taxonomy}", $term, $request, false );

		$schema = $this->get_item_schema();
		if ( ! empty( $schema['properties']['meta'] ) && isset( $request['meta'] ) ) {
			$meta_update = $this->meta->update_value( $request['meta'], $term->term_id );

			if ( is_wp_error( $meta_update ) ) {
				return $meta_update;
			}
		}

		$fields_update = $this->update_additional_fields_for_object( $term, $request );

		if ( is_wp_error( $fields_update ) ) {
			return $fields_update;
		}

		$request->set_param( 'context', 'view' );

		$response = $this->prepare_item_for_response( $term, $request );

		return rest_ensure_response( $response );
	}