Crash when trying to save tool scene

[VojtaStruhar]

Tested versions

v4.4.stable.official [4c311cb]

System information

Godot v4.4.stable - macOS Sequoia (15.3.2) - Multi-window, 2 monitors - Metal (Forward+) - integrated Apple M2 (Apple8) - Apple M2 (8 threads)

Issue description

I'm working on a portals plugin, where a @tool script spawns other nodes while being set up.

When I toggle is_teleport boolean to true in the inspector, the script creates an Area3D node with a CollisionShape3D child. Both are stored in exported property fields.

When I set the is_teleport to false, I only call queue_free only on the area, assuming the collider will get cleaned up too (it's the area's child). But it does not - it remains visible in the inspector exported field. When I try to save, the editor crashes.

My guess would be that it tries to serialize a freed node. When I manually clear the collider property, it saves fine.

Steps to reproduce

I've uploaded a MRP, so this is in relation to that.

1. Cmd + A Add new "Portal" node (the script will get suggested)
2. Toggle is_teleport to true, which spawns two nodes. These nodes are visible in the exported properties.

3. Toggle is_teleport to false. Both nodes disappear from the scene tree, but the collision shape remains in one of the exported fields.
4. Try to save - Cmd + S

5. The editor crashes

Minimal reproduction project (MRP)

This is all the code there is to it:

MRP:
mvp-crash.zip

[VojtaStruhar]

I mean just setting teleport_collider = null on line 28 solves the issue.. It's a dumb mistake I made once and discovered immediately. But since it crashes the editor, I thought I'd report it anyways.

[AThousandShips]

I don't think this is a bug, access to null variables will crash code and not sure the editor is expected to catch this safely

[VojtaStruhar]

Fair enough. The documentation clearly says that with tool script you are playing with fire a little bit :)

I was curious and made some debug prints:

print("Teleport area: ", teleport_area)
print("is_valid: ", is_instance_valid(teleport_area))
print("Collider: ", teleport_collider)
print("is_valid: ", is_instance_valid(teleport_collider))

In the "invalid state" it results in this being printed:

Teleport area: <null>
is_valid: false
Collider: <Freed Object>
is_valid: false

That means godot knows if something is freed! I was thinking maybe something along the lines of is_instance_valid check in C++ would prevent this issue. I'm not too familiar with the engine internals, no idea how complex that would be.