python/cpython · warning · ValueError

AIX_BUILDDATE is not defined or invalid: {build_date!r}

Error message

AIX_BUILDDATE is not defined or invalid: {build_date!r}

What it means

In debug mode, BaseSelectorEventLoop.sock_recv() verifies the socket is non-blocking before scheduling the read, because a blocking socket could freeze the loop while the coroutine thinks it is async. The check (self._debug and sock.gettimeout() != 0) raises ValueError so the misuse surfaces immediately rather than as a mysterious hang.

Source

Thrown at Lib/_aix_support.py:106

    # type: () -> List[int]
    gnu_type = sysconfig.get_config_var("BUILD_GNU_TYPE")
    if not gnu_type:
        raise ValueError("BUILD_GNU_TYPE is not defined")
    return _aix_vrtl(vrmf=gnu_type)


def aix_buildtag():
    # type: () -> str
    """
    Return the platform_tag of the system Python was built on.
    """
    # AIX_BUILDDATE is defined by configure with:
    # lslpp -Lcq bos.rte | awk -F:  '{ print $NF }'
    build_date = sysconfig.get_config_var("AIX_BUILDDATE")
    try:
        build_date = int(build_date)
    except (ValueError, TypeError):
        raise ValueError(f"AIX_BUILDDATE is not defined or invalid: "
                         f"{build_date!r}")
    return _aix_tag(_aix_bgt(), build_date)

View on GitHub (pinned to bc6749cc3b)

Solutions

1. Set sock.setblocking(False) (or settimeout(0.0)) before any await loop.sock_recv on it
2. Route blocking-configured sockets through regular thread-based I/O instead of loop sock_* APIs
3. Standardize a helper that creates loop-ready sockets (socket + setblocking(False)) for all async paths

Example fix

# before
sock = socket.create_connection((host, port))  # blocking
await loop.sock_recv(sock, 4096)  # debug: ValueError
# after
sock = socket.create_connection((host, port))
sock.setblocking(False)
await loop.sock_recv(sock, 4096)

def nb(sock):
    if sock.gettimeout() != 0:
        sock.setblocking(False)
    return sock

data = await loop.sock_recv(nb(sock), 4096)

try:
    await loop.sock_recv(sock, n)
except ValueError as e:
    if 'non-blocking' in str(e):
        sock.setblocking(False)
        return await loop.sock_recv(sock, n)
    raise

When it happens

Trigger: Enabling asyncio debug mode and calling await loop.sock_recv(sock, n) with a socket in blocking mode or with a positive timeout — the socket default (timeout None) triggers it as soon as debug is on. Sockets from socket.create_connection or third-party connection helpers usually arrive blocking.

Common situations: Turning on PYTHONASYNCIODEBUG or debug=True to diagnose a hang, and this earlier error appears; sockets created by libraries (paho, protobuf RPC layers) with settimeout(30) then passed to sock_*; tests that enable loop debug globally via fixtures.

Related errors

• Must run this script from the repo root
• write() argument must be str, not {type(s).__name__}
• write() argument must be bytes-like, not {type(b).__name__}
• write() argument must be str, not {type(s).__name__}
• write() argument must be bytes-like, not {type(b).__name__}

AI-assisted analysis of python/cpython@bc6749cc3b (2026-08-14). Data as JSON: /api/errors/d8c3d54491a08d1d. Report an issue: GitHub.