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fix(rtc): send and receive data packets without a new ctypes array type - #912
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publish_data built a `ctypes.c_byte * data_len` array type for each new payload length, and the data packet receive path did the same with `ctypes.POINTER(ctypes.c_byte * data_len)`. Each ctypes array type is a reference cycle, so every packet of a new length left garbage that only the cyclic garbage collector can free. Pass the address of the bytes payload directly on the send side, and read the received buffer with ctypes.string_at, as FfiClient.request already does.
zek
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changt,
cloudwebrtc,
lukasIO and
xianshijing-lk
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October 28, 2026 18:29
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Closes #911.
publish_dataand the data packet receive path built actypes.c_byte * data_lenarray type for each new payload length. On Python 3.12 and 3.13 the receive side keeps these types alive for the life of the process (thectypes.POINTER()cache holds them). On Python 3.14 each type is cyclic garbage.bytespayload withget_address. The native library copies the data during the request, as fix(rtc): pass the FFI request bytes without a new ctypes array type #847 already relies on inFfiClient.request. This also removes the per-byte(*payload)unpack.ctypes.string_at, asFfiClientdoes for event buffers.The new test
test_publish_data_makes_no_ctypes_array_typesends 10 payloads of new lengths, waits for the receiver to get them, and makes sure that no array type with these lengths exists. It also makes sure that the received payloads are intact.Before and after
repro.pyfrom #911, against a local LiveKit server (v1.13.5). The "this branch" rows use the branch source with the native library from the livekit 1.2.0 wheel:gc.collect(): 0, array types still alive: 100gc.collect(): 1300, array types still alive: 0Tests (
livekit-rtc/tests/test_dc.py):test_publish_data_makes_no_ctypes_array_typetest_dc.pyandtest_ffi_client.pytests