get_mesh_arrays() generates nonsensical ARRAY_INDEX values

[UQuark]

Godot version

4.0, 4.1 stable

System information

Godot v4.1.stable - Arch Linux #1 ZEN SMP PREEMPT_DYNAMIC Tue, 04 Jul 2023 08:39:22 +0000 - Vulkan (Mobile) - dedicated AMD Radeon RX 6700 XT (RADV NAVI22) () - AMD Ryzen 5 5600X 6-Core Processor (12 Threads)

Issue description

I'm trying to modify PlaneMesh geometry with code (via MeshDataTool).
To do that, I construct ArrayMesh and copy PlaneMesh's arrays to it (obtained with get_mesh_arrays()).
It works perfectly on PC, but failed on Android.
The error was:

E 0:00:01:0300   Soil.gd:23 @ _fill_grass(): Index r[i] = 16256 is out of bounds (vcount = 144).
  <C++ Source>   scene/resources/mesh_data_tool.cpp:72 @ create_from_surface()
  <Stack Trace>  Soil.gd:23 @ _fill_grass()
                 Soil.gd:15 @ _ready()

After some debugging I found out that arrays 12th array (ARRAY_INDEX as is declared here) is full of seemingly leftover uninitialized junk.

PC values:

Android values:

Steps to reproduce

1. Create a new project
2. Add a node, attach a script
3. Put

        var pm = PlaneMesh.new()
	var arrays = pm.get_mesh_arrays()

4. Set a breakpoint
5. Run with remote debug on an Android device
6. Observe arrays 12th element going nuts in Stack Variables

Minimal reproduction project

test.zip

[AThousandShips]

• Duplicate of: Mobile Renderer makes Meshes unreadable/uneditable on Android #75599

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