Fixed renaming/reparenting/duplicating a node disabling editable_children

[Piet-G]

Fixed renaming/reparenting/duplicating a node disabling editable_children.

This should fix #20409 & fix #6455 and probably some others I missed.

[reduz]

This is a really difficult issue to fix without introducing many hacks, and we are too close to 3.1 alpha to risk breaking more things.
Eventually plan is for next version to re-evaluate how all this data is stored in hopes of simplifying the system.

[Piet-G]

Yeah currently it seems almost impossible to solve this problem without a bunch of hacks with the current way the editable_children data is stored.

[akien-mga]

Sorry for the lack of update in over a year :|

I'm unsure on how to proceed with this PR. There are various issues with the approach uses, especially the fact that it adds many new methods and signals to the public node API which have no real reason to be in the public API. As @reduz mentioned, the approach used is a bit hacky, but a non-hacky solution is likely difficult to use right now.

I think this PR should likely be closed, but we need to have some pointers on how the two referenced bugs should be fixed in a clearer manner. Especially whether any fix should wait on:

Eventually plan is for next version to re-evaluate how all this data is stored in hopes of simplifying the system.

And when would this happen in the roadmap.

[aaronfranke]

@Piet-G Is this still desired? If so, it needs to be rebased on the latest master branch.

If not, abandoned pull requests will be closed in the future as announced here.

[aaronfranke]

This PR has not received any new commits for almost 2 years and is abandoned, closing.

The "salvageable" tag applies, anyone is welcome to take this PR and update/finish it.