Unreleased double singletons feature issues

[bitwes]

The double_singleton and partial_double_singleton features have been disabled in 7.3.0 and the wiki documentation has been removed. When trying to create a demo project using Engine and OS I found numerous issues that were not discovered in the initial testing using Input. The feature was inspired by use with Input, but some of the other common uses were not explored fully.

Issues found:

• In testing Input it appeared that all methods related to Input had a method id > 1000. Everything less than 1000 was ignored. This is not the case for OS. The other classes were not examined further. Changing the code to add every method > 200 seemed to fix OS, but without further investigation we can't be sure how doubles of other singletons will behave.
• It appears that a double of Engine did not get the editor_hint property. I was able to stub the is_editor_hint() method, but directly using the property editor_hint resulted in an error.

This feature will have to be explored further before it can be released.

The double_singleton and partial_double_singleton methods have been hardcoded to return null and tests have been commented out. This was found at the last minute and I hope to re-introduce the feature in the next release. If not, then I will remove the commented out stuff then. Hooray tech-debt!

[lars-hoeck]

Hey, is this feature dead? I think it's a pretty important feature.

[bitwes]

This is not dead, but I haven't got around to reworking the problem. It is still high on the priority list, but most of my efforts recently have been dealing with Godot 4.0.