Using the same export_group name in an inherited class and re-saving that class while the project is running crashes the project and sometimes the editor

[nan0m]

Godot version

4.1.0

System information

Windows 10, i711800H, Forward+ Vulkan

Issue description

When using @export_group("Name") in a BaseClass, then inheriting from that BaseClass in another class and there also using @export_group("Name"), with the same group name, then running the project and re-saving the inherited class the project crashes with

ERROR: FATAL: Index p_index = 3 is out of bounds (size() = 3).
   at: get (./core/templates/cowdata.h:155)

sometimes the editor crashes too after a while.

Steps to reproduce

1. open reproduction project
2. Run the project.
3. Open the "super"script
4. Press CTRL + S to save it.

Minimal reproduction project

MRP_.zip

[ghost]

I can confirm that it crashes the project with the reproduction steps and project provided.
I did not manage to make the editor itself crash.

After first downloading the project it crashed on every CTRL + S, without any changes made to the script.
After opening it for the second time, it took more tries, up to ~50.

Modifying the export_group name while running and saving almost always causes an project crash.

Two different errors are printed, but only when running with the external console:

• the first one happens when resaving script with no changes:

ERROR: FATAL: Index p_index = 3 is out of bounds (size() = 3).
   at: get (./core/templates/cowdata.h:155)

• the second one is thrown when the script is modified before saving:

ERROR: FATAL: Index p_index = 3 is out of bounds (((Vector<T> *)(this))->_cowdata.size() = 3).
   at: operator[] (./core/templates/vector.h:52)

My system:

• v4.1.1.stable.official.bd6af8e0e - Windows 10.0.19045 - Vulkan (Compatibility) - GeForce GT 540M- Intel Core i7-2670QM CPU @ 2.20GHz (8 Threads)

[dalexeev]

I tested the MRP and it looks like PR #78254 fixes this issue too. Note, however, that there are several other bugs with hot reloading of scripts (when you edit the script while the project is running).