Assertion failed in Godot 4

By Eduardo Orellana · Updated

An assert() in your code was given a false condition. assert(hp > 0, "hp must be positive") with hp = 0 stops with Assertion failed: hp must be positive. The assert is doing its job: find why the condition is false at that point, here an hp that was never set above 0.

Download for macOSDownload for WindowsDownload for LinuxDownload for ChromebookDownloading…

AppImage, x86_64. Ubuntu 22.04, Debian 12, Fedora 39 or newer.

Intel or AMD Chromebook, with Linux turned on.

Download for macOSDownload for Windows

What Godot is checking

assert(condition, message) checks the condition in debug builds. When it is false the VM stops the function with Assertion failed, followed by the message if one was given, and the debugger breaks there in the editor.

Asserts are compiled out of release exports: the condition is not even evaluated. Never put code with a side effect, such as a function that changes state, inside an assert.

Reproduce it

An assert that hp is positive, with hp still 0.

extends Node

var hp := 0

func _ready() -> void:
	assert(hp > 0, "hp must be positive")
	print("after")

What Godot 4.7.2 prints

Godot Engine v4.7.2.stable.mono.official.ed1daf0bf - https://godotengine.org

SCRIPT ERROR: Assertion failed: hp must be positive
   at: _ready (res://answers/assertion-failed/repro.gd:6)
   GDScript backtrace (most recent call first):
       [0] _ready (res://answers/assertion-failed/repro.gd:6)

Fix it

Give hp its starting value before the code that relies on it.

extends Node

var hp := 0

func _ready() -> void:
	hp = 100
	assert(hp > 0, "hp must be positive")
	print("hp ", hp)

What the fixed script prints

Godot Engine v4.7.2.stable.mono.official.ed1daf0bf - https://godotengine.org

hp 100

Verified on Godot 4.7.2

Both scripts on this page were run headless on Godot 4.7.2 (4.7.2.stable.mono.official.ed1daf0bf) on 18 October 2026, and the output above is what Godot printed, unedited.

Where the check lives in Godot's source: [gdscript_vm.cpp line 3895, the message with your text](https://github.com/godotengine/godot/blob/4.7.2-stable/modules/gdscript/gdscript_vm.cpp#L3895), [assert in the @GDScript class reference](https://github.com/godotengine/godot/blob/4.7.2-stable/modules/gdscript/doc_classes/@GDScript.xml).

Questions

Does assert() run in an exported game?
Not in a release export. Asserts run in the editor and in debug exports only.
What does Assertion failed. without text mean?
The same check, from an assert() given no message. Add a message as the second argument so the error says what was expected.