ReferenceError: weakly-referenced object no longer exists

[whitphx]

2022-08-31 21:30:45.453 Uncaught app exception
Traceback (most recent call last):
  File "/path/to/streamlit-webrtc-article-tutorial-sample/.venv/lib/python3.9/site-packages/streamlit/runtime/scriptrunner/script_runner.py", line 556, in _run_script
    exec(code, module.__dict__)
  File "/path/to/streamlit-webrtc-article-tutorial-sample/app.py", line 21, in <module>
    webrtc_streamer(
  File "/path/to/streamlit-webrtc-article-tutorial-sample/.venv/lib/python3.9/site-packages/streamlit_webrtc/component.py", line 514, in webrtc_streamer
    session_info = get_this_session_info()
  File "/path/to/streamlit-webrtc-article-tutorial-sample/.venv/lib/python3.9/site-packages/streamlit_webrtc/session_info.py", line 43, in get_this_session_info
    current_server = get_current_server()
  File "/path/to/streamlit-webrtc-article-tutorial-sample/.venv/lib/python3.9/site-packages/streamlit_webrtc/server.py", line 52, in get_current_server
    servers = [obj for obj in gc.get_objects() if isinstance(obj, Server)]
  File "/path/to/streamlit-webrtc-article-tutorial-sample/.venv/lib/python3.9/site-packages/streamlit_webrtc/server.py", line 52, in <listcomp>
    servers = [obj for obj in gc.get_objects() if isinstance(obj, Server)]
ReferenceError: weakly-referenced object no longer exists

requirements.txt

opencv-python-headless==4.5.4.60
streamlit==1.11.1
streamlit-webrtc==0.43.2

import streamlit as st
from streamlit_webrtc import webrtc_streamer
import av
import cv2

st.title("My first Streamlit app")
st.write("Hello, world")

threshold1 = st.slider("Threshold1", min_value=0, max_value=1000, step=1, value=100)
threshold2 = st.slider("Threshold2", min_value=0, max_value=1000, step=1, value=200)

def callback(frame):
    img = frame.to_ndarray(format="bgr24")

    img = cv2.cvtColor(cv2.Canny(img, threshold1, threshold2), cv2.COLOR_GRAY2BGR)

    return av.VideoFrame.from_ndarray(img, format="bgr24")

webrtc_streamer(
    key="example",
    video_frame_callback=callback,
    rtc_configuration={  # Add this line
        "iceServers": [{"urls": ["stun:stun.l.google.com:19302"]}]
    }
)

Python 3.9.13

[creeksflowing]

I tried the same and I get the same error

[whitphx]

Thank you for the report!

[whitphx]

Hypothesis: This problem occurs on M1 mac with Python built for arm arch.

[creeksflowing]

Hypothesis: This problem occurs on M1 mac with Python built for arm arch.

Most likely, currently working on M1. As soon as I can I'll try on a Intel Mac and report back.

[whitphx]

Thank you!

Apart from that, I will release a new version which will suppress this error ASAP.

[whitphx]

I released v0.43.3 with the fix for this.

Please let me know if there are still problems!

[kargarisaac]

Hello,

What was the problem? I face the same problem on m1 with deepcopy. Looking for a solution.

Thank you

[whitphx]

I haven't investigated it so well and don't know the actual reason. I just added try-except to catch the error (see the PR linked above) because it was ok to ignore the error in my case.

My hypothesis is that there are something around the garbage collector in the ARM-build Python, but I don't know the details and I don't have the fundamental solution.