I believe @laoneo is going to work on this next week :)

To make all the legacy code JTable::getInstance work again in 4, the extension classmap needs to be extended with all core tables as we already did in #16435 here https://github.com/joomla/joomla-cms/blame/4.0-dev/libraries/extensions.classmap.php#L16.

By the way we have the same issue with models JModelLegacy::getInstance does also not work anymore.

A quick update on this issue here. It all comes down to the question to what degree we want to make it possible to let the model and table objects instanciation being overrideable. At the moment the getInstance calls of JModelLegacy::getInstance has been replaced by direct creating the object, for example here https://github.com/joomla/joomla-cms/blob/4.0-dev/administrator/modules/mod_latest/mod_latest.php#L15. If we want to go more the service way, then it needs a bigger rewrite of the MVCFactory.

We shouldn't be direct instantiating anything in the MVC layer except for inside factories. The current getInstance() methods allow a semi-clean way to overload component classes and the direct instantiation method basically means that the only way to accomplish it is with autoloader manipulation. As much as I disagree with the concept of class overloading, I do agree with being able to override the logic to load objects (I'd rather people be able to subclass things and put their customizations in place versus encouraging core classes to be overloaded since at that point you can't rely on the API being stable and that's where you get the bug reports about missing methods in core classes after an upgrade) so we should try our hardest to make use of the factories and only go to a direct instantiation model if we can't make it work.

Lets take the example of the sample data blog plugin which needs models from different extensions. To properly fix it, I see two possible ways:

1. A global factory which creates the MVCFactories:

$container->get(MVCFactoryFactoryInterface::class)->createFactory('Joomla\\Component\\Content')->createModel('Articles', 'Administrator');
$container->get(MVCFactoryFactoryInterface::class)->createFactory('Joomla\\Component\\Categories\')->createModel('Category', 'Administrator');

2. Extend the MVC factory that it can load models, views and tables from different extensions, by passing the full class name (the MVCFactory should get properly injected or loaded from the container on some point):

$factory = new MVCFactory('', $app);
$factory->createModel(ArticlesModel::class);
$factory->createModel(CategoryModel::class);

Decision with @mbabker, @wilsonge and @laoneo:
We go with $container->get(MVCFactoryFactoryInterface::class)->createFactory('com_content')->createModel('Articles', 'Administrator');.

Guess we can close this one as we have a pr #19835.

Set to "closed" on behalf of @franz-wohlkoenig by The JTracker Application at issues.joomla.org/joomla-cms/17705

closed as having Pull Request #19835