Is there a way to autoload Forms / Fields in Custom J5 Module?

Question

If I want to add a Subform to my Module I need to specify the "formsource" (path to xml) into my fieldsettings. But is there a way to use The Autoloader and "simply" use the Form name? In the docs it's written "[...]formsource (mandatory) the form source to be included. A relative path to the xml file (relative to the root folder for the installed Joomla site) or a valid form name which can be found by JForm::getInstance()..." So my question now is - is there a way to use the name here also in modules now?

So when using the new Filestructure for Modules I think i need to register the namespace for Forms (and Fields) in my provider.php, and if so how to do this ?

My current provider.php:

return new class() implements ServiceProviderInterface
{
    public function register(Container $container): void
    {
        $container->registerServiceProvider( new ModuleDispatcherFactory('\\CMP\\Module\\Modulename'));
        $container->registerServiceProvider( new HelperFactory('\\CMP\\Module\\Modulename\\Site\\Helper'));
        $container->registerServiceProvider( new Module());
    }
};

File Structure:

mod_modulename
 - forms
 -- subform.xml
 ...
 - services
 -- provider.php
 - src
 -- Dispatcher
 - mod_modulename.xml
 ...

mod_modulename.xml:

...
<field 
   name="title_source_params"
   type="subform"
   formsource="modules.mod_modulename.subform"
/>
...

Error: Joomla\CMS\Form\Form::getInstance() could not load file

Again, I know i could simply paste in the path to the xml in the formsource but does it work / what do I need to do to use the formname instead?

Answer 1

No, documentation is wrong and this wouldn't make much sense anyways. Joomla\CMS\Form\Form::getInstance() can either retrieve a cached form instance by name or create a new one. But in order to create a new instance, a valid XML file or XML string is required. Your subform is the first time where your form is being instantiated so the XML file/source is mandatory. Anyways, Joomla\CMS\Form\Form::getInstance() is deprecated. Form instances will no longer be cached in the future.