Can't pickle local object ManticoreEVM.finalize on 0.3.6

[Pet3ris]

Summary of the problem

Issues running manticore on a very simple contract.

Manticore version

Manticore 0.3.6

Python version

3.9

OS / Environment

Mac OS X 11.2.2

Dependencies

Step to reproduce the behavior

In a Conda environment

pip3 install manticore # installs latest 0.3.6
manticore example.sol

where example is:

contract Simple {
    function f(uint a) payable public{
        if (a == 65) {
            revert();
        }
    }
}

Expected behavior

Successful run.

Actual behavior

Raises the following error AttributeError: Can't pickle local object 'ManticoreEVM.finalize.<locals>.worker_finalize.

Any relevant logs

2021-10-19 15:57:00,199: [68957] m.c.manticore:WARNING: Manticore is only supported on Linux. Proceed at your own risk!
2021-10-19 15:57:00,359: [68957] m.main:INFO: Registered plugins: IntrospectionAPIPlugin, <class 'manticore.ethereum.plugins.SkipRevertBasicBlocks'>, <class 'manticore.ethereum.plugins.FilterFunctions'>
2021-10-19 15:57:00,359: [68957] m.main:INFO: Beginning analysis
2021-10-19 15:57:00,363: [68957] m.e.manticore:INFO: Starting symbolic create contract
2021-10-19 15:57:00,693: [68957] m.e.manticore:INFO: Starting symbolic transaction: 0
2021-10-19 15:57:01,274: [68957] m.e.manticore:INFO: 1 alive states, 1 terminated states
2021-10-19 15:57:01,343: [68957] m.e.manticore:INFO: Starting symbolic transaction: 1
2021-10-19 15:57:01,981: [68957] m.e.manticore:INFO: 1 alive states, 1 terminated states
Traceback (most recent call last):
  File "/usr/local/bin/manticore", line 8, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.9/site-packages/manticore/__main__.py", line 42, in main
    ethereum_main(args, logger)
  File "/usr/local/lib/python3.9/site-packages/manticore/ethereum/cli.py", line 145, in ethereum_main
    m.finalize(only_alive_states=args.only_alive_testcases)
  File "/usr/local/lib/python3.9/site-packages/manticore/core/manticore.py", line 177, in newFunction
    return func(self, *args, **kw)
  File "/usr/local/lib/python3.9/site-packages/manticore/ethereum/manticore.py", line 1768, in finalize
    proc.start()
  File "/usr/local/Cellar/python@3.9/3.9.7/Frameworks/Python.framework/Versions/3.9/lib/python3.9/multiprocessing/process.py", line 121, in start
    self._popen = self._Popen(self)
  File "/usr/local/Cellar/python@3.9/3.9.7/Frameworks/Python.framework/Versions/3.9/lib/python3.9/multiprocessing/context.py", line 224, in _Popen
    return _default_context.get_context().Process._Popen(process_obj)
  File "/usr/local/Cellar/python@3.9/3.9.7/Frameworks/Python.framework/Versions/3.9/lib/python3.9/multiprocessing/context.py", line 284, in _Popen
    return Popen(process_obj)
  File "/usr/local/Cellar/python@3.9/3.9.7/Frameworks/Python.framework/Versions/3.9/lib/python3.9/multiprocessing/popen_spawn_posix.py", line 32, in __init__
    super().__init__(process_obj)
  File "/usr/local/Cellar/python@3.9/3.9.7/Frameworks/Python.framework/Versions/3.9/lib/python3.9/multiprocessing/popen_fork.py", line 19, in __init__
    self._launch(process_obj)
  File "/usr/local/Cellar/python@3.9/3.9.7/Frameworks/Python.framework/Versions/3.9/lib/python3.9/multiprocessing/popen_spawn_posix.py", line 47, in _launch
    reduction.dump(process_obj, fp)
  File "/usr/local/Cellar/python@3.9/3.9.7/Frameworks/Python.framework/Versions/3.9/lib/python3.9/multiprocessing/reduction.py", line 60, in dump
    ForkingPickler(file, protocol).dump(obj)
AttributeError: Can't pickle local object 'ManticoreEVM.finalize.<locals>.worker_finalize'

[ekilmer]

Update on this... I also recently encountered this issue. Python 3.7 doesn't show this error, but Python 3.8 has the error, so something changed from Python 3.7 and 3.8.

Unfortunately, I don't have or know of a fix for this 😕