Modules aren't visible until after __init__ finishes

[timholy]

#23579 changed how modules are loaded. I thought it best to file #23579 (comment) as an issue. The reason turned out to be that #23579 changed behavior of when the module becomes "visible": it used to be that you could refer to the module from outside code that got called via __init__ or one of the registered Base.package_callbacks. Now you have to defer such references until after __init__ finishes.

Code example at timholy/Revise.jl#48 (only the first commit). This new behavior might be intended, in which case please close this issue.

[JeffBezanson]

The change is intentional. In the new way of doing things, top-level modules don't have Main as their parent module. Since Main is no longer special, assigning X to its module after using X in Main is the last step (the same as in all other modules).

Looking up a top-level module can be done with Base.root_module(name) and replacing one can be done with Base.register_root_module(name, mod).

[timholy]

Thanks, now I understand #23579 a bit better. I attributed the timing issue to be separate, but now it makes much more sense.