Source
File: wp-includes/class-wp-block-type-registry.php
public function register( $name, $args = array() ) {
$block_type = null;
if ( $name instanceof WP_Block_Type ) {
$block_type = $name;
$name = $block_type->name;
}
if ( ! is_string( $name ) ) {
$message = __( 'Block type names must be strings.' );
_doing_it_wrong( __METHOD__, $message, '5.0.0' );
return false;
}
if ( preg_match( '/[A-Z]+/', $name ) ) {
$message = __( 'Block type names must not contain uppercase characters.' );
_doing_it_wrong( __METHOD__, $message, '5.0.0' );
return false;
}
$name_matcher = '/^[a-z0-9-]+\/[a-z0-9-]+$/';
if ( ! preg_match( $name_matcher, $name ) ) {
$message = __( 'Block type names must contain a namespace prefix. Example: my-plugin/my-custom-block-type' );
_doing_it_wrong( __METHOD__, $message, '5.0.0' );
return false;
}
if ( $this->is_registered( $name ) ) {
/* translators: %s: Block name. */
$message = sprintf( __( 'Block type "%s" is already registered.' ), $name );
_doing_it_wrong( __METHOD__, $message, '5.0.0' );
return false;
}
if ( ! $block_type ) {
$block_type = new WP_Block_Type( $name, $args );
}
$this->registered_block_types[ $name ] = $block_type;
return $block_type;
}