Make IMessageHub implement IDisposable about easy.messagehub

[NimaAra]

Okay thanks, this should now be fixed in v3.3.0

Please validate and let me know how it goes.

[NimaAra]

This should not be the case. The idea is that MessageHub will be registered against IMessageHub in a container and only the class initializing the container or the container itself should be able to dispose the hub otherwise a consumer (publisher or subscriber) could by mistake dispose the hub resulting in other consumers being unable to publish or subscribe.

[bed007]

When the hub is registered in a Ioc container (DryIoc for instance) as a Singleton, when the container is disposed to clear all registration, the hub is also Disposed which is OK. The problem is that, once the hub is disposed, there is notting else to do to instanciate a new hub instance. The IMessageHub singleton instance is disposed and unusable and since the ctor is private, there is no way to have a working hub again. We need to kill the process. Any solution or fix in mind ?

[bed007]

Ok, in DryIoc there is a flag you can set to prevent it from calling Dispose on a registration. But I think that having a hub that cannot work anymore and the only solution is to kill the process is a bad thing.. no ?

[NimaAra]

That is a valid ask.

My question to you so that I can understand your use-case better is why would you want to dispose the hub and then use it again?

The reasoning behind the current behaviour is that you would only dispose it at the application/process exit, if your intent is to clear existing subscriptions then why not invoke the relevant method?

[bed007]

Well I agree this is not a common case. What is happening is that we are using it in a Xamarin.Forms application. The actual steps to reproduce my case are the following (for Android only):

1. Boostrap the DryIoc container by registering all services when MainActivity (XF apps are typically single activity apps)
2. Do stuff...
3. Back button is pressed at the root page, the MainActivity is then Destroyed. At this point, we want to Dispose the DryIoc which call Dispose on all IDisposable registration.
4. We start the application from the launcher icon again. At this point, and this is the uncommon part (!), the MainActivity is created again and the container is getting boostrapped again. But since we just destroy the MainActivity but did not kill the application, the App was still "alive" and all static content was preserved, thus the MessageHub is disposed and cannot be used anymore.

The main point here is that calling Dispose on the MessageHub make the whole library useless after that point. There is no way of getting the MessageHub up again in the same process.