Simple Kivy app crashes (release unlocked lock) - kivy

Question

I am getting the following error when trying to run even the simplest of Kivy apps:
C:\Users\kprice\Desktop>python test.py
[INFO ] [Logger ] Record log in C:\Users\kprice\AppData\Roaming\SPB_16.6\.kivy\logs\kivy_17-03-03_57.txt
[INFO ] [Kivy ] v1.9.2.dev0, git-9f2daa0, 20170302
[INFO ] [Python ] v3.6.0 (v3.6.0:41df79263a11, Dec 23 2016, 08:06:12) [MSC v.1900 64 bit (AMD64)]
[INFO ] [Factory ] 193 symbols loaded
[INFO ] [Image ] Providers: img_tex, img_dds, img_sdl2, img_gif (img_pil, img_ffpyplayer ignored)
[INFO ] [Text ] Provider: sdl2
[INFO ] [OSC ] using <thread> for socket
[INFO ] [Window ] Provider: sdl2
[INFO ] [GL ] Using the "OpenGL" graphics system
[INFO ] [GL ] GLEW initialization succeeded
[INFO ] [GL ] Backend used <glew>
[INFO ] [GL ] OpenGL version <b'4.3.0 - Build 10.18.15.4256'>
[INFO ] [GL ] OpenGL vendor <b'Intel'>
[INFO ] [GL ] OpenGL renderer <b'Intel(R) HD Graphics 4400'>
[INFO ] [GL ] OpenGL parsed version: 4, 3
[INFO ] [GL ] Shading version <b'4.30 - Build 10.18.15.4256'>
[INFO ] [GL ] Texture max size <16384>
[INFO ] [GL ] Texture max units <32>
[INFO ] [Shader ] fragment shader: <b"WARNING: 0:6: '' : #version directive missing">
[INFO ] [Shader ] vertex shader: <b"WARNING: 0:6: '' : #version directive missing">
[INFO ] [Window ] auto add sdl2 input provider
[INFO ] [Window ] virtual keyboard not allowed, single mode, not docked
Traceback (most recent call last):
File "test.py", line 13, in <module>
MyApp().run()
File "C:\Users\kprice\AppData\Local\Programs\Python\Python36\lib\site-packages\kivy\app.py", line 802, in run
root = self.build()
File "test.py", line 10, in build
return Label(text='Hello world')
File "C:\Users\kprice\AppData\Local\Programs\Python\Python36\lib\site-packages\kivy\uix\label.py", line 291, in __init__
self._trigger_texture()
File "kivy\_clock.pyx", line 75, in kivy._clock.ClockEvent.__call__ (kivy\_clock.c:2223)
RuntimeError: release unlocked lock
The code for the app is as follows:
from kivy.app import App
from kivy.uix.label import Label
class MyApp(App):
def build(self):
return Label(text='Hello world')
if __name__ == '__main__':
MyApp().run()
Any ideas on why even the most basic program seems to crash?

Answer 1

That was a typo for a change in the kivy.clock code. It basically called the method twice, which it shouldn't (no thread lock to release).
I'm not sure if it's because of Cython or because of Windows, but I believe that error should return a ThreadError. There is too small amount of RuntimeErrors in Kivy, so I'm not sure why does it return a wrong type of error.