Large number of standalone context creation fails about moderngl HOT 3 CLOSED

Hi, as I remember we do not rely on __del__ for resource handling. we have a .realease() method in most cases.
We also have some stress test in the utils. I get back with a more detailed answer when my time allows it.

from moderngl.

Right. My including of del ctx is pointless anyway, as it as not additional effect since ctx is reassigned.

Adding ctx.release() solves the issue:

import moderngl

for i in range(1000):
    if (i % 50) == 0:
        print(f"iteration {i}")
    ctx = moderngl.create_context(standalone=True)
    ctx.release()

Output:

iteration 0
iteration 50
iteration 100
iteration 150
iteration 200
iteration 250
iteration 300
iteration 350
iteration 400
iteration 450
iteration 500
iteration 550
iteration 600
iteration 650
iteration 700
iteration 750
iteration 800
iteration 850
iteration 900
iteration 950

I'll let you close the issue unless you feel there is something to be done still, may be a note in the docs?

from moderngl.

Related docs page: manually-releasing-objects

Some notes that pop into my mind:

• We do not use __del__ due to it is not reliable and it can be entirely prevented with a dangling ref to the object. The simplest I can think of is storing context in it's extra field.

• Most of the ModernGL objects hold a ref to the context mostly to have access to the gl calls. Without properly implementing tp_traverse the GC won't find the island of dead objects just by loosing all the refs from the main code.

• __del__ might be called without having an active gl context making a fault when calling opengl functions.

• some objects cannot be released, for example when the OpenGL context was lost or destroyed by the window.

from moderngl.