Executing MeshInstance.new()._mesh_changed() crashes Godot

[qarmin]

Godot version:
Godot 3.2.4 rc 2

Issue description:

MeshInstance.new()._mesh_changed()

cause crash with backtrace

scene/3d/mesh_instance.cpp:704:42: runtime error: member call on null pointer of type 'struct Mesh'
scene/3d/mesh_instance.cpp:704:42: runtime error: member access within null pointer of type 'struct Mesh'
handle_crash: Program crashed with signal 11
Dumping the backtrace. Please include this when reporting the bug on https://github.com/godotengine/godot/issues
[1] godots() [0x16f757a] (/mnt/Miecz/godot3.2/platform/x11/crash_handler_x11.cpp:54)
[2] /lib/x86_64-linux-gnu/libc.so.6(+0x46210) [0x7f4619ec3210] (??:0)
[3] MeshInstance::_mesh_changed() (/mnt/Miecz/godot3.2/scene/3d/mesh_instance.cpp:704)
[4] MethodBind0::call(Object*, Variant const**, int, Variant::CallError&) (/mnt/Miecz/godot3.2/./core/method_bind.gen.inc:61 (discriminator 4))
[5] Object::call(StringName const&, Variant const**, int, Variant::CallError&) (/mnt/Miecz/godot3.2/core/object.cpp:919 (discriminator 1))
[6] Variant::call_ptr(StringName const&, Variant const**, int, Variant*, Variant::CallError&) (/mnt/Miecz/godot3.2/core/variant_call.cpp:1129 (discriminator 1))
[7] GDScriptFunction::call(GDScriptInstance*, Variant const**, int, Variant::CallError&, GDScriptFunction::CallState*) (/mnt/Miecz/godot3.2/modules/gdscript/gdscript_function.cpp:1089)
[8] GDScriptInstance::call(StringName const&, Variant const**, int, Variant::CallError&) (/mnt/Miecz/godot3.2/modules/gdscript/gdscript.cpp:1238)
[9] Object::call(StringName const&, Variant const**, int, Variant::CallError&) (/mnt/Miecz/godot3.2/core/object.cpp:898 (discriminator 1))
[10] Variant::call_ptr(StringName const&, Variant const**, int, Variant*, Variant::CallError&) (/mnt/Miecz/godot3.2/core/variant_call.cpp:1129 (discriminator 1))
[11] GDScriptFunction::call(GDScriptInstance*, Variant const**, int, Variant::CallError&, GDScriptFunction::CallState*) (/mnt/Miecz/godot3.2/modules/gdscript/gdscript_function.cpp:1089)
[12] GDScriptInstance::_ml_call_reversed(GDScript*, StringName const&, Variant const**, int) (/mnt/Miecz/godot3.2/modules/gdscript/gdscript.cpp:1269)
[13] GDScriptInstance::call_multilevel_reversed(StringName const&, Variant const**, int) (/mnt/Miecz/godot3.2/modules/gdscript/gdscript.cpp:1278)
[14] Node::_notification(int) (/mnt/Miecz/godot3.2/scene/main/node.cpp:152)
[15] Node::_notificationv(int, bool) (/mnt/Miecz/godot3.2/./scene/main/node.h:46 (discriminator 14))
[16] CanvasItem::_notificationv(int, bool) (/mnt/Miecz/godot3.2/./scene/2d/canvas_item.h:166 (discriminator 3))
[17] Node2D::_notificationv(int, bool) (/mnt/Miecz/godot3.2/./scene/2d/node_2d.h:38 (discriminator 3))
[18] Object::notification(int, bool) (/mnt/Miecz/godot3.2/core/object.cpp:931)
[19] Node::_propagate_ready() (/mnt/Miecz/godot3.2/scene/main/node.cpp:197)
[20] Node::_propagate_ready() (/mnt/Miecz/godot3.2/scene/main/node.cpp:186 (discriminator 2))
[21] Node::_set_tree(SceneTree*) (/mnt/Miecz/godot3.2/scene/main/node.cpp:2560)
[22] SceneTree::init() (/mnt/Miecz/godot3.2/scene/main/scene_tree.cpp:464)
[23] OS_X11::run() (/mnt/Miecz/godot3.2/platform/x11/os_x11.cpp:3628)
[24] godots(main+0x331) [0x16ee467] (/mnt/Miecz/godot3.2/platform/x11/godot_x11.cpp:57)
[25] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf3) [0x7f4619ea40b3] (??:0)
[26] godots(_start+0x2e) [0x16ee07e] (??:?)

[angad-k]

So, there should be a simple null check here, right? :

void MeshInstance3D::_mesh_changed() {
	materials.resize(mesh->get_surface_count());
}

[akien-mga]

Yes.

[angad-k]

Okay. Sending a PR

[angad-k]

Godot 4.0 errors out and doesn't let me call the function itself. Error :

Invalid call. Nonexistent function '_mesh_changed' in base 'MeshInstance3D'.

So, I guess the error is 3.2 specific then...