`ViewportTexture` emits `Path to node is invalid` error in the editor.

[pmoosi]

Tested versions

• Reproducible since Rework scene preview thumbnails (reverted) #102313

System information

Godot v4.5.beta.mono (0b2170d) - Ubuntu 24.04.2 LTS 24.04 on Wayland - X11 display driver, Multi-window, 3 monitors - Vulkan (Forward+) - integrated AMD Radeon Graphics (RADV RENOIR) - AMD Ryzen 7 5800H with Radeon Graphics (16 threads) - 13.49 GiB memory

Issue description

Using a ViewportTexture in a scene prints:

ERROR: Path to node is invalid: 'SubViewport'.
   at: _setup_local_to_scene (scene/main/viewport.cpp:197)

whenever the scene is saved (or the thumbnail is generated I guess?).

The culprit seems to be #102313.

I tried #107630 but it does not fix it.

Steps to reproduce

The mrp contains a SubViewport and a Sprite2D with a ViewportTexture. Changing something and then saving the scene emits the errors.

Minimal reproduction project (MRP)

mrp.zip

[ryevdokimov]

@daniel080400

I get something similar while trying to save, but with this error for instanced scenes, so I don't think it's exclusive to any specific type of node, so I'm not sure what the relationship with the errors are, since I have other scenes that save fine.

ERROR: Node not found: "%Conveyor" (relative to "/root/@EditorNode@20467/@Panel@14/@VBoxContainer@15/DockHSplitLeftL/DockHSplitLeftR/DockHSplitMain/@VBoxContainer@26/DockVSplitCenter/@EditorBottomPanel@7323/@VBoxContainer@7308/@MarginContainer@21065/@SubViewport@21421/BeltConveyorAssembly").

Also tried #107630 without success.

[daniel080400]

@pmoosi The MRP you provided has a corrupted scene (inherited.tscn) which will lead to crash before #107630 is merged

[daniel080400]

Opened a PR to fix this: #107676

[pmoosi]

Sorry for the corrupt mrp, that was an oversight on my end (no idea how it happened - i thought I removed the scene ;)). But thanks for fixing it anyways. I can confirm that it is fixed.