Division by zero crashes editor and builds instead of logging error message

[kebabskal]

Godot version

v4.2.beta1.official [b137180]

System information

Godot v4.2.beta1 - Windows 10.0.22621 - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 2070 (NVIDIA; 31.0.15.3640) - AMD Ryzen 7 5800X 8-Core Processor (16 Threads)

Issue description

When you are dividing ints by 0 builds and editor hard crashes.
In 4.1.2, both editor and builds, there's an error message logged.
(Editor crashes only happen when using @tool)

Floats doesn't crash, and doesn't log an error, instead it results in "inf".

The editor warns about division by zero if you try 1/0 etc.
Boxing the divisor in a variable yields no warning:

var zero:int = 0
1/zero	

Steps to reproduce

1. Open the supplied minimal project in Godot 4.2 beta 1
2. Press "Run Project"
3. Observe the float example resulting in "inf" and then a hard crash when it tries to do the same with ints

Minimal reproduction project

div-by-zero-bug.zip

Edit: Fixed erroneous godot version. Got confused and copied from the wrong window.

[akien-mga]

Godot version

Godot v4.1.2.stable

To clarify, I believe you meant to report this against 4.2-beta1.

I tested locally on Linux with 4.2-beta1 and it's not crashing for me:

Might be Windows specific.

[kebabskal]

To clarify, I believe you meant to report this against 4.2-beta1.

Good eye, sniper!
My bad. Updated the issue, copying from the right godot instance.

Might be Windows specific.

Does seem like it, yes. The other person replicating this over on chat.godotengine.org also ran Windows.

[Wierdox]

Oh right I forgot to post the console log for when I replicated the crash on rocket chat. Not sure if it's any use though. I could only get the backtrace when using my custom build of 4.2(probably my fault), but I got the same crash on the official.

Got this from var x :int= 5 % str_to_var("0")

================================================================
CrashHandlerException: Program crashed
Engine version: Godot Engine v4.2.beta.custom_build (7b33ad354a1884c027487892f2e44e8cc6862076)
Dumping the backtrace. Please include this when reporting the bug to the project developer.
[0] OperatorEvaluatorModNZ<__int64,__int64,__int64>::validated_evaluate (D:\godot\core\variant\variant_op.h:294)
[1] OperatorEvaluatorModNZ<__int64,__int64,__int64>::validated_evaluate (D:\godot\core\variant\variant_op.h:294)
[2] GDScriptFunction::call (D:\godot\modules\gdscript\gdscript_vm.cpp:686)
[3] GDScriptFunctionState::resume (D:\godot\modules\gdscript\gdscript_function.cpp:222)
[4] GDScriptFunctionState::_signal_callback (D:\godot\modules\gdscript\gdscript_function.cpp:166)
[5] MethodBindVarArgTR<GDScriptFunctionState,Variant>::call (D:\godot\core\object\method_bind.h:265)
[6] Object::callp (D:\godot\core\object\object.cpp:774)
[7] Callable::callp (D:\godot\core\variant\callable.cpp:69)
[8] CallableCustomBind::call (D:\godot\core\variant\callable_bind.cpp:145)
[9] Callable::callp (D:\godot\core\variant\callable.cpp:58)
[10] Object::emit_signalp (D:\godot\core\object\object.cpp:1129)
[11] Object::emit_signal<> (D:\godot\core\object\object.h:920)
[12] SceneTree::process_timers (D:\godot\scene\main\scene_tree.cpp:584)
[13] SceneTree::process (D:\godot\scene\main\scene_tree.cpp:520)
[14] Main::iteration (D:\godot\main\main.cpp:3603)
[15] OS_Windows::run (D:\godot\platform\windows\os_windows.cpp:1474)
[16] widechar_main (D:\godot\platform\windows\godot_windows.cpp:182)
[17] _main (D:\godot\platform\windows\godot_windows.cpp:206)
[18] main (D:\godot\platform\windows\godot_windows.cpp:218)
[19] __scrt_common_main_seh (D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288)
[20] <couldn't map PC to fn name>
-- END OF BACKTRACE --
================================================================

Edit: forgot debug symbols.

[AThousandShips]

Please build with debug symbols

[Wierdox]

Furthermore, backtrace of the repro:

float: div by zero: inf

================================================================
CrashHandlerException: Program crashed
Engine version: Godot Engine v4.2.beta.custom_build (7b33ad354a1884c027487892f2e44e8cc6862076)
Dumping the backtrace. Please include this when reporting the bug to the project developer.
[0] OperatorEvaluatorDivNZ<__int64,__int64,__int64>::validated_evaluate (D:\godot\core\variant\variant_op.h:181)
[1] OperatorEvaluatorDivNZ<__int64,__int64,__int64>::validated_evaluate (D:\godot\core\variant\variant_op.h:181)
[2] GDScriptFunction::call (D:\godot\modules\gdscript\gdscript_vm.cpp:686)
[3] GDScriptInstance::callp (D:\godot\modules\gdscript\gdscript.cpp:1849)
[4] Node::_notification (D:\godot\scene\main\node.cpp:187)
[5] Node2D::_notificationv (D:\godot\scene\2d\node_2d.h:37)
[6] Object::notification (D:\godot\core\object\object.cpp:839)
[7] Node::_propagate_ready (D:\godot\scene\main\node.cpp:232)
[8] Node::_propagate_ready (D:\godot\scene\main\node.cpp:221)
[9] Node::_set_tree (D:\godot\scene\main\node.cpp:2941)
[10] OS_Windows::run (D:\godot\platform\windows\os_windows.cpp:1470)
[11] widechar_main (D:\godot\platform\windows\godot_windows.cpp:182)
[12] _main (D:\godot\platform\windows\godot_windows.cpp:206)
[13] main (D:\godot\platform\windows\godot_windows.cpp:218)
[14] __scrt_common_main_seh (D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288)
[15] <couldn't map PC to fn name>
-- END OF BACKTRACE --
================================================================

[bitsawer]

Tested on Windows 10 on current master (a574c02), I get the crash too. Error message is

Stop reason: Exception 0xc0000094 encountered at address 0x7ff7d0032079

0xc0000094 is Windows SEH code for EXCEPTION_INT_DIVIDE_BY_ZERO, which makes sense. Error happens here, because argument right is zero:

godot/core/variant/variant_op.h

Line 181 in a574c02

*VariantGetInternalPtr<R>::get_ptr(r_ret) = *VariantGetInternalPtr<A>::get_ptr(left) / *VariantGetInternalPtr<B>::get_ptr(right);

Looks like the basic OperatorEvaluatorDivNZ::evaluate() function does have a check for zero division, but the validated_evaluate() and ptr_evaluate() versions don't:

godot/core/variant/variant_op.h

Lines 166 to 187 in a574c02

	template <class R, class A, class B>
	class OperatorEvaluatorDivNZ {
	public:
	static void evaluate(const Variant &p_left, const Variant &p_right, Variant *r_ret, bool &r_valid) {
	const A &a = *VariantGetInternalPtr<A>::get_ptr(&p_left);
	const B &b = *VariantGetInternalPtr<B>::get_ptr(&p_right);
	if (b == 0) {
	r_valid = false;
	*r_ret = "Division by zero error";
	return;
	}
	*r_ret = a / b;
	r_valid = true;
	}
	static inline void validated_evaluate(const Variant *left, const Variant *right, Variant *r_ret) {
	*VariantGetInternalPtr<R>::get_ptr(r_ret) = *VariantGetInternalPtr<A>::get_ptr(left) / *VariantGetInternalPtr<B>::get_ptr(right);
	}
	static void ptr_evaluate(const void *left, const void *right, void *r_ret) {
	PtrToArg<R>::encode(PtrToArg<A>::convert(left) / PtrToArg<B>::convert(right), r_ret);
	}
	static Variant::Type get_return_type() { return GetTypeInfo<R>::VARIANT_TYPE; }
	};

[miv391]

It seems that all OperatorEvaluators in https://github.com/godotengine/godot/blob/a574c0296b38d5f786f249b12e6251e562c528cc/core/variant/variant_op.h suffer from the same problem. If the evaluate() checks some error situations, validated_evaluate() and ptr_evaluate() either crash or return something weird. Some examples:

	var a := -1
	print(12 << a) # prints "0" instead of error message

	var b := 0
	print(12 % b) # crashes