PHP driven error messages in Sugar v7 - Works for sidecar and BWC modules

errors.php

// Assuming that $b is a valid bean instance...
// Assuming we are editing the record...

// On SugarApiException($app_strings[$error_app_label], null, null, 422, 'my_error_code_sample');
// "my_error_code_sample" is displayed on the output as "error"
// $app_strings[$error_app_label] is displayed on the output as "error_message"

$error_app_label = 'LBL_MY_ERROR_MESSAGE';
if(!empty($b->module_name) && isModuleBWC($b->module_name))
{
    SugarApplication::appendErrorMessage($app_strings[$error_app_label]);

    $urlParameters = array(
            'module' => $b->module_name,
            'action' => 'EditView'
            );

    if(!empty($b->id))
    {
        $urlParameters['record'] = $b->id;
    }

    $url = 'index.php?' . http_build_query($urlParameters);
    SugarApplication::redirect($url);
}
else
{
    throw new SugarApiException($app_strings[$error_app_label], null, null, 422, 'my_error_code_sample');
}