This PR is not possible, this would break all plugins overriding the registerListeners method, which means you can't have a plugin which supports 4 and 5.

We need this in a way which is b/c.

It's true that existing plugins with overridden method would need to be updated to account for the new method signature. But such plugins will work with both 4.0 and 5.0. This is mentioned in the manual. And when interface method signature is changed again in 6.0 to require a dispatcher instance, no changes will be necessary. So a plugin that's updated with 5.0 signature today will end up working with 4.0, 5.0 and 6.0.

We need this in a way which is b/c.

Interesting. Can you post a link to the new versioning policy of Joomla? I've seen claims that it supposedly follows SemVer but that seems to have changed.

This changes can be done in b/c way, without changing method signatures:

• keep DispatcherAwareInterface interface
• call $plugin->setDispatcher($dispatcher) in PluginHelper::import(), as it already is
• modify registerListeners() to throw an exception when $this->getDispatcher() return trash.

@laoneo what would you say?

This changes can be done in b/c way, without changing method signatures:

* keep `DispatcherAwareInterface` interface

* call `$plugin->setDispatcher($dispatcher)` in `PluginHelper::import()`, as it already is

* modify `registerListeners()` to throw an exception when `$this->getDispatcher()` return trash.

?‍♂️
The point here is to get rid of the totally misused DispatcherAwareInterface. But, apparently, the project is going backwards, introducing -aware interfaces in places where they absolutely don't belong.

Why it is not belong, what is belong then? Sorry, I do not understand, maybe my knowledge just not enogh.
In current case for me no big diference here if it DispatcherAwareInterface or PotatoInterface ;)

I can also sugest other way around, without DispatcherAwareInterface:

• add new method to PluginInterface, kind of registerListenersInDispatcher(?DispatcherInterface $dispatcher = null);
• deprecate registerListeners()
• add use of new method, and proxy it to registerListeners(), untill 6.x

And add description why and when registerListeners() should be removed, and replaced with new method.
Because after 1 year no one will remember what the heck is going on.

Hmhm, or you mean that DispatcherAwareInterface should be used only when Class triggers some event?
Well, then it may have a sense, even though it not an obvious thing.
Then a new method should be a less risky change, than changing existing, in current case.

So I think that removing the Dispatcher as a constructor argument is a good thing.

My only question would be do we want to go down this approach OR to have the dispatcher get the events out (which is how I think this was intended to work originally using the subscriber interface - i.e. https://github.com/joomla/joomla-cms/pull/39387/files#diff-76977b095cc108785d3c5026e26a2df447db05cd1ad28a0a22820cf72573965bR230-R234 ). I always assumed once we removed support for Joomla 3.x style plugins and moved people over to SubscriberInterface that we'd remove the entire registerListeners method.

introducing -aware interfaces in places where they absolutely don't belong

I totally agree with this.

This pull request has been automatically rebased to 5.1-dev.

This pull request has been automatically rebased to 5.2-dev.

I'm sorry, but looking at the registerListener, this wont be able to be merged into 5.x and would have to wait for 6.0 at least.

This pull request has been automatically rebased to 5.3-dev.