testSimpleActorAsk50K functional test failing on MacOS with multiprocUDPBase

[gbanasiak]

Thespian version: recent snapshot (acf5cb2)

OS version:
MacOS Sequoia 15.2

% sw_vers
ProductName:		macOS
ProductVersion:		15.2
BuildVersion:		24C101

Description:

% py.test -v -k testSimpleActorAsk50K
=============================================================================================== test session starts ================================================================================================
platform darwin -- Python 3.12.2, pytest-8.3.4, pluggy-1.5.0 -- /Users/grzegorz/src/Thespian/.venv/bin/python
cachedir: .pytest_cache
rootdir: /Users/grzegorz/src/Thespian
collected 2722 items / 2716 deselected / 6 selected

thespian/test/test_bigmessages.py::TestFuncSimpleActorOperations::testSimpleActorAsk50K[simpleSystemBase] PASSED                                                                                             [ 16%]
thespian/test/test_bigmessages.py::TestFuncSimpleActorOperations::testSimpleActorAsk50K[multiprocQueueBase] PASSED                                                                                           [ 33%]
thespian/test/test_bigmessages.py::TestFuncSimpleActorOperations::testSimpleActorAsk50K[multiprocUDPBase] FAILED                                                                                             [ 50%]
thespian/test/test_bigmessages.py::TestFuncSimpleActorOperations::testSimpleActorAsk50K[multiprocTCPBase] PASSED                                                                                             [ 66%]
thespian/test/test_bigmessages.py::TestFuncSimpleActorOperations::testSimpleActorAsk50K[multiprocTCPBase-AdminRouting] PASSED                                                                                [ 83%]
thespian/test/test_bigmessages.py::TestFuncSimpleActorOperations::testSimpleActorAsk50K[multiprocTCPBase-AdminRoutingTXOnly] PASSED                                                                          [100%]

===================================================================================================== FAILURES =====================================================================================================
______________________________________________________________________ TestFuncSimpleActorOperations.testSimpleActorAsk50K[multiprocUDPBase] _______________________________________________________________________

self = <thespian.test.test_bigmessages.TestFuncSimpleActorOperations object at 0x102a7a300>, asys = <thespian.actors.ActorSystem object at 0x1012cbaa0>

    def testSimpleActorAsk50K(self, asys):
        whale = asys.createActor(Whale)
        shrimp = asys.createActor(Shrimp)
        testdata = (10*1024, 'hello')
        r = asys.ask(shrimp, testdata, askTimeout)
        assert r == 'hello'
        r = asys.ask(whale, testdata, askTimeout)
>       assert r == 'hello' * 10 * 1024
E       AssertionError: assert None == (('hello' * 10) * 1024)

thespian/test/test_bigmessages.py:54: AssertionError
----------------------------------------------------------------------------------------------- Captured stdout call -----------------------------------------------------------------------------------------------
Declaring transmit of TransportIntent(ActorAddr-(UDP|:61084)-pending-ExpiresIn_0:04:59.998085-<class 'str'>-hellohellohellohellohellohellohellohellohellohellohellohellohellohellohellohellohellohellohellohellohellohellohellohellohellohellohellohellohellohello...-quit_0:04:59.998079) as Poison: Traceback (most recent call last):
  File "/Users/grzegorz/src/Thespian/thespian/system/systemCommon.py", line 173, in _send_intent_to_transport
    self.transport.scheduleTransmit(self._addrManager, intent)
  File "/Users/grzegorz/src/Thespian/thespian/system/transport/asyncTransportBase.py", line 214, in scheduleTransmit
    self._schedulePreparedIntent(transmitIntent, has_exclusive_flag=has_exclusive_flag)
  File "/Users/grzegorz/src/Thespian/thespian/system/transport/asyncTransportBase.py", line 316, in _schedulePreparedIntent
    if not self._runQueued(has_exclusive_flag=has_exclusive_flag):
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/grzegorz/src/Thespian/thespian/system/transport/asyncTransportBase.py", line 146, in _runQueued
    self._submitTransmit(nextTransmit)
  File "/Users/grzegorz/src/Thespian/thespian/system/transport/asyncTransportBase.py", line 333, in _submitTransmit
    self._scheduleTransmitActual(transmitIntent, has_exclusive_flag=has_exclusive_flag)
  File "/Users/grzegorz/src/Thespian/thespian/system/transport/UDPTransport.py", line 267, in _scheduleTransmitActual
    r = self.socket.sendto(transmitIntent.serMsg,
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
OSError: [Errno 40] Message too long
Traceback (most recent call last):

  File "/Users/grzegorz/src/Thespian/thespian/system/systemCommon.py", line 173, in _send_intent_to_transport
    self.transport.scheduleTransmit(self._addrManager, intent)

  File "/Users/grzegorz/src/Thespian/thespian/system/transport/asyncTransportBase.py", line 214, in scheduleTransmit
    self._schedulePreparedIntent(transmitIntent, has_exclusive_flag=has_exclusive_flag)

  File "/Users/grzegorz/src/Thespian/thespian/system/transport/asyncTransportBase.py", line 316, in _schedulePreparedIntent
    if not self._runQueued(has_exclusive_flag=has_exclusive_flag):
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

  File "/Users/grzegorz/src/Thespian/thespian/system/transport/asyncTransportBase.py", line 146, in _runQueued
    self._submitTransmit(nextTransmit)

  File "/Users/grzegorz/src/Thespian/thespian/system/transport/asyncTransportBase.py", line 333, in _submitTransmit
    self._scheduleTransmitActual(transmitIntent, has_exclusive_flag=has_exclusive_flag)

  File "/Users/grzegorz/src/Thespian/thespian/system/transport/UDPTransport.py", line 267, in _scheduleTransmitActual
    r = self.socket.sendto(transmitIntent.serMsg,
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

OSError: [Errno 40] Message too long

================================================================================================= warnings summary =================================================================================================
thespian/test/test_bigmessages.py::TestFuncSimpleActorOperations::testSimpleActorAsk50K[multiprocUDPBase]
thespian/test/test_bigmessages.py::TestFuncSimpleActorOperations::testSimpleActorAsk50K[multiprocTCPBase]
thespian/test/test_bigmessages.py::TestFuncSimpleActorOperations::testSimpleActorAsk50K[multiprocTCPBase-AdminRouting]
thespian/test/test_bigmessages.py::TestFuncSimpleActorOperations::testSimpleActorAsk50K[multiprocTCPBase-AdminRoutingTXOnly]
  /Users/grzegorz/.pyenv/versions/3.12.2/lib/python3.12/multiprocessing/popen_fork.py:66: DeprecationWarning: This process (pid=45664) is multi-threaded, use of fork() may lead to deadlocks in the child.
    self.pid = os.fork()

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
============================================================================================= short test summary info ==============================================================================================
FAILED thespian/test/test_bigmessages.py::TestFuncSimpleActorOperations::testSimpleActorAsk50K[multiprocUDPBase] - AssertionError: assert None == (('hello' * 10) * 1024)
============================================================================= 1 failed, 5 passed, 2716 deselected, 4 warnings in 5.52s =============================================================================

There is a simple explanation:

% sudo sysctl net.inet.udp.maxdgram
net.inet.udp.maxdgram: 9216

After sudo sysctl net.inet.udp.maxdgram=65535 the test passes.

[kquick]

Thank you for looking into this.