Custom PShape: if used with add_child() doesn't render

[adigiosaffatte]

I tried to run the following code:

from p5 import *

star = None

def setup():
    global star
    size(3000, 1200)
    star = PShape()
    rect_shp = rect(300,300,100,100)
    star.add_child(rect_shp)

def draw():
    global star
    background(125)
    draw_shape(star)

I'm expecting to see a rectangle on my screen but I can't see anything.
I found that function draw_shape(shape, pos=(0, 0, 0)) defined in primitives.py (line 791) begins with the following statement:

p5.renderer.render(shape)

and only AFTER handles the children:

for child_shape in shape.children:
    draw_shape(child_shape)

I think this behaviour is incorrect, the function should check the presence of children before calling p5.renderer.render(shape).
In fact, I tried to modify the function in this way:

def draw_shape(shape, pos=(0, 0, 0)):
    if isinstance(shape, Geometry):
        return
    
    elif not len(shape.children):
        p5.renderer.render(shape)

    else:
        for child_shape in shape.children:
            draw_shape(child_shape)

and it worked: I was able to render my rectangle!

What do you think?
Am I using the custom PShape in the wrong manner or it is actually a bug?

Thank you!

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