Can select children of instanced scene while it doesn't have editable children

[lentsius-bark]

Godot version:
3.2.4.rc.custom_build / 3.2.4.rc1 (both exhibit the same behaviour)

System
Linux (PopOS - most recent, up to date including drivers), GLES3, Nvidia 1060 - laptop

Issue description:
This is a really weird bug. It only affects projects created with previous versions of Godot.
As of rc1 i believe, the 3d editor unreliably alters between selecting the instanced scene or its children.
No errors whatsoever. In the screenshot below you can see:

• instanced scene which doesnt have editable children
• first click on the scene selected one of its children
• understandably the node is not highlighted in the scene tree as it's not there at all.

Steps to reproduce:
Open a project created in 3.2.3 or lower

Minimal reproduction project:
Sadly I am not in possession of a minimal reproduction project, I've only got bigger ones, which I don't mind sharing if it'd help and you don't mind downloading a bigger project.

[akien-mga]

Might be related to physics picking changes @RandomShaper?

[RandomShaper]

@akien-mga, maybe. I'll check it.

@lentsius-bark, yes, please share the project. That'll help me a lot.

[lentsius-bark]

@RandomShaper here you go. I stripped the project of unnecessary parts but the problem persists on my end.

If you navigate to a scene called LeGame.tscn and try selecting the "DeliveryBox", or parts of the character on the sword it exhibits the aforementioned behaviour.

SwordSurfers-picking-test.zip

Thanks for looking into this!

[RandomShaper]

Bisected down to 6dbc086.

It made this code section not work as expected:

godot/editor/plugins/spatial_editor_plugin.cpp

Line 537 in db8c241

while (item->get_owner() && item->get_owner() != edited_scene && !edited_scene->is_editable_instance(item->get_owner())) {

I've unassigned myself. I'd gladly try to fix it, but I don't think I'll have time.

[RandomShaper]

That said, if no one willing and able to fix it pops up soon, I'll try to find a spot to do it myself to help unblocking the release.

[akien-mga]

CC @hilfazer @KoBeWi

[hilfazer]

That said, if no one willing and able to fix it pops up soon, I'll try to find a spot to do it myself to help unblocking the release.

I'll give it a try once i'm back from work.
However, i won't be able to check it on Linux, only on Windows.

[lentsius-bark]

@hilfazer i can test it on Linux.

[hilfazer]

Testing project: https://github.com/hilfazer/Projects/tree/EngineIssues/Godot/EngineIssues/SelectingHiddenNodesIn3DandCanvasEditors_godot32

Projects created in 3.2.4 are affected as well.

The bug is caused by the new way of storing Editable Children information. The code found by RandomShaper will need to change, tomorrow i'll try to figure it out.

Edit:
I think i might have a fix for that. I'll make a PR soon.