[Compatibility] Add Module#const_added

[itarato]

Source: #3039

Module#const_added has been added. [Feature #17881]

[eregon]

I worry that this feature, which causes an extra method call for every constant assignment, can significantly slow down loading code.
I'm thinking we could optimize e.g. by having a global boolean constAddedDefined in RubyContext, and only call if there ever was a definition of const_added (not counting the empty core one).

Also we'd be able to remove the currentNode != null && coreLibrary != null && coreLibrary.isLoaded() check and just use that boolean instead which seems nice.
Maybe @andrykonchin can do that to speed up the integration of this PR?

Longer-term when we have vtable for methods we could use that to quickly check if const_added on a given module is the core one and in that case do nothing.

[itarato]

I worry that this feature, which causes an extra method call for every constant assignment, can significantly slow down loading code. I'm thinking we could optimize e.g. by having a global boolean constAddedDefined in RubyContext, and only call if there ever was a definition of const_added (not counting the empty core one).

Also we'd be able to remove the currentNode != null && coreLibrary != null && coreLibrary.isLoaded() check and just use that boolean instead which seems nice. Maybe @andrykonchin can do that to speed up the integration of this PR?

Longer-term when we have vtable for methods we could use that to quickly check if const_added on a given module is the core one and in that case do nothing.

Sure thing, I let you make that change. Thanks!

[andrykonchin]

Merged in cd498f7