Fix Command Queue Crash

[reduz]

• No longer allow sending an object (texture) to the server as material parameter
• Keep a parameter cache locally in ShaderMaterial

Fixes #49895
Fixes #49201

[lyuma]

Here are two related issues reported which show CommandQueueMT in the stacktrace, both filed within the past two weeks (post rewrite):
#49895 and #50039 (marked as duplicate)

AndreaCatania reported a similar issue in rocketchat, but I think a GitHub issue was never filed. Here are the stacktraces from June 23, and later on June 27th respectively:

Interestingly, there was one issue filed on May 29th, before CommandQueue was rewritten, which indicates 8b19ffd as the commit which caused the issue:
#49201

[akien-mga]

Here are two related issues reported which show CommandQueueMT in the stacktrace, both filed within the past two weeks (post rewrite):
#49895 and #50039 (marked as duplicate)

Tested, this PR doesn't fix #49895.

[reduz]

@akien-mga that is odd, judging from the stack trace it should, I will give it a check later today.

[reduz]

@akien-mga Not sure what you tested, but: #49895 does not crash for me, the new code catches the error properly:
ERROR: Condition "p_value.get_type() == Variant::OBJECT" is true.
That said, this still requires fixing because sending objects to the server is no longer allowed, I seem to have forgotten the particles here, so I will amend to the PR that fix.

[reduz]

Ok, I think it should be perfect now, went all cases of material_set_param and id not find anything else that could cause trouble.

[akien-mga]

Edit: Ignore this, I was testing an older version.

#49895 still crashes for me with the current commit of this PR:

set parameter: hue_variation_random
set parameter: anim_speed_random
set parameter: anim_offset_random
set parameter: color_value
ERROR: Condition "p_value.get_type() == Variant::OBJECT" is true.
   at: material_set_param (servers/rendering/renderer_rd/renderer_storage_rd.cpp:1595)

Thread 1 "godot-git" received signal SIGSEGV, Segmentation fault.
0x0000000000000000 in ?? ()
(gdb) bt
#0  0x0000000000000000 in ?? ()
#1  0x0000000002348967 in CommandQueueMT::_flush (this=0xa8e8e08) at ./core/templates/command_queue_mt.h:373
#2  0x00000000053bc116 in CommandQueueMT::flush_if_pending (this=0xa8e8e08) at ./core/templates/command_queue_mt.h:404
#3  0x00000000054ae732 in RenderingServerDefault::free (this=0xa8e8c90, p_rid=...) at servers/rendering/rendering_server_default.h:860
#4  0x0000000004fcad2a in GradientTexture::~GradientTexture (this=0x7fff34003e30, __in_chrg=<optimized out>) at scene/resources/texture.cpp:1752
#5  0x000000000238c5b6 in memdelete<RefCounted> (p_class=0x7fff34003e30) at ./core/os/memory.h:115
#6  0x0000000005b724e2 in Variant::_clear_internal (this=0x7fff3400a388) at core/variant/variant.cpp:1309
#7  0x000000000216e7d7 in Variant::clear (this=0x7fff3400a388) at ./core/variant/variant.h:257
#8  0x000000000216e7fc in Variant::~Variant (this=0x7fff3400a388, __in_chrg=<optimized out>) at ./core/variant/variant.h:672
#9  0x00000000054d3796 in CommandQueueMT::Command3<RendererStorage, void (RendererStorage::*)(RID, StringName const&, Variant const&), RID, StringName, Variant>::~Command3 (this=0x7fff3400a358, 
    __in_chrg=<optimized out>) at ./core/templates/command_queue_mt.h:322
#10 0x0000000002348995 in CommandQueueMT::_flush (this=0xa8e8e08) at ./core/templates/command_queue_mt.h:375
#11 0x00000000053bc116 in CommandQueueMT::flush_if_pending (this=0xa8e8e08) at ./core/templates/command_queue_mt.h:404
#12 0x00000000054ab980 in RenderingServerDefault::canvas_item_add_triangle_array (this=0xa8e8c90, p1=..., p2=..., p3=..., p4=..., p5=..., p6=..., p7=..., p8=..., p9=-1)
    at servers/rendering/rendering_server_default.h:766
#13 0x0000000004f73218 in StyleBoxFlat::draw (this=0xd665fd0, p_canvas_item=..., p_rect=...) at scene/resources/style_box.cpp:774
#14 0x0000000004873ca1 in Tabs::_notification (this=0xcd9f720, p_what=30) at scene/gui/tabs.cpp:353
#15 0x000000000487f838 in Tabs::_notificationv (this=0xcd9f720, p_notification=30, p_reversed=false) at scene/gui/tabs.h:38
#16 0x0000000005dd32a5 in Object::notification (this=0xcd9f720, p_notification=30, p_reversed=false) at core/object/object.cpp:841
#17 0x000000000458501f in CanvasItem::_update_callback (this=0xcd9f720) at scene/main/canvas_item.cpp:427
#18 0x00000000023992fd in call_with_variant_args_helper<__UnexistingClass>(__UnexistingClass*, void (__UnexistingClass::*)(), Variant const**, Callable::CallError&, IndexSequence<>) (p_instance=0xcd9f720, 
--Type <RET> for more, q to quit, c to continue without paging--
    p_method=(void (__UnexistingClass::*)(__UnexistingClass * const)) 0x4584f30 <CanvasItem::_update_callback()>, p_args=0x7fffffffc9c8, r_error=...) at ./core/variant/binder_common.h:218
#19 0x0000000002398a3b in call_with_variant_args_dv<__UnexistingClass> (p_instance=0xcd9f720, p_method=(void (__UnexistingClass::*)(__UnexistingClass * const)) 0x4584f30 <CanvasItem::_update_callback()>, 
    p_args=0x0, p_argcount=0, r_error=..., default_values=...) at ./core/variant/binder_common.h:365
#20 0x0000000002397a2e in MethodBindT<>::call(Object*, Variant const**, int, Callable::CallError&) (this=0xb60aff0, p_object=0xcd9f720, p_args=0x0, p_arg_count=0, r_error=...) at ./core/object/method_bind.h:285
#21 0x0000000005dd3188 in Object::call (this=0xcd9f720, p_method=..., p_args=0x0, p_argcount=0, r_error=...) at core/object/object.cpp:832
#22 0x0000000005b69d35 in Callable::call (this=0x7ffff5a43038, p_arguments=0x0, p_argcount=0, r_return_value=..., r_call_error=...) at core/variant/callable.cpp:62
#23 0x0000000005dcbeb7 in MessageQueue::_call_function (this=0xa0c75c0, p_callable=..., p_args=0x7ffff5a43050, p_argcount=0, p_show_error=false) at core/object/message_queue.cpp:258
#24 0x0000000005dcc1d6 in MessageQueue::flush (this=0xa0c75c0) at core/object/message_queue.cpp:304
#25 0x00000000045f568c in SceneTree::process (this=0xab6a720, p_time=0.149999619) at scene/main/scene_tree.cpp:449
#26 0x00000000021afc6d in Main::iteration () at main/main.cpp:2541
#27 0x0000000002170937 in OS_LinuxBSD::run (this=0x7fffffffd270) at platform/linuxbsd/os_linuxbsd.cpp:278
#28 0x000000000216d8da in main (argc=2, argv=0x7fffffffd788) at platform/linuxbsd/godot_linuxbsd.cpp:58

System specs:

System:    Host: cauldron Kernel: 5.12.14-desktop-3.mga9 x86_64 bits: 64 Desktop: KDE Plasma 5.21.5 Distro: Mageia 9 mga9 
CPU:       Info: Quad Core model: Intel Core i7-8705G bits: 64 type: MT MCP cache: L2: 8 MiB 
           Speed: 1716 MHz min/max: 800/3100 MHz Core speeds (MHz): 1: 1716 2: 1067 3: 902 4: 856 5: 834 6: 831 7: 860 8: 845 
Graphics:  Device-1: Intel HD Graphics 630 driver: i915 v: kernel 
           Device-2: Advanced Micro Devices [AMD/ATI] Polaris 22 XL [Radeon RX Vega M GL] driver: amdgpu v: kernel 
           Device-3: Cheng Uei Precision Industry (Foxlink) HP Wide Vision FHD Camera type: USB driver: uvcvideo 
           Display: x11 server: Mageia X.org 1.20.11 driver: loaded: intel,v4l resolution: 1920x1080~60Hz 
           OpenGL: renderer: Mesa Intel HD Graphics 630 (KBL GT2) v: 4.6 Mesa 21.1.4

[akien-mga]

I was testing the wrong commit previously. After testing the right commit, I can confirm it works fine and fixes #49895.

[akien-mga]

Thanks!