Bug when using `functools.partial` with `FunctionExecutor.map()`

[TomNicholas]

Lithops is incorrectly raising anytime I try to pass in a function decorated with functools.partial.

It complains that the function I decorated does not have a __call__ method

import functools
import lithops

fexec = lithops.FunctionExecutor()

iterable = ["foo", "bar"]
kwargs = {}

def f(s: str, **kwargs):
    return s.upper()

futures = fexec.map(f, iterable, **kwargs)  # this works fine
print(fexec.get_result(futures))

partial_f = functools.partial(f, **kwargs)
futures = fexec.map(partial_f, iterable)  # this fails
print(fexec.get_result(futures))

.venv/lib/python3.13/site-packages/lithops/executors.py:259: in map
    job = create_map_job(
.venv/lib/python3.13/site-packages/lithops/job/job.py:81: in create_map_job
    job = _create_job(
.venv/lib/python3.13/site-packages/lithops/job/job.py:245: in _create_job
    func_and_data_ser, mod_paths = serializer([func] + iterdata, inc_modules, exc_modules)
.venv/lib/python3.13/site-packages/lithops/job/serialize.py:73: in __call__
    ref_modules.update(self._module_inspect(obj))
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <lithops.job.serialize.SerializeIndependent object at 0x12138c690>, obj = functools.partial(<function test_lithops_functools_partial_bug.<locals>.f at 0x1214ef7e0>)

    def _module_inspect(self, obj):
        """
        inspect objects for module dependencies
        """
        worklist = []
        seen = set()
        mods = set()
    
        if inspect.isfunction(obj) or (inspect.ismethod(obj) and inspect.isfunction(obj.__func__)):
            # The obj is the user's function
            worklist.append(obj)
    
        elif type(obj).__name__ == 'cython_function_or_method':
            for k, v in linspect.getmembers_static(obj):
                if k == '__globals__':
                    mods.add(v['__file__'])
    
        elif type(obj) is dict:
            # the obj is the user's iterdata
            for param in obj.values():
                if type(param).__module__ == "__builtin__":
                    continue
                elif inspect.isfunction(param):
                    # it is a user defined function
                    worklist.append(param)
                else:
                    # it is a user defined class
                    for k, v in linspect.getmembers_static(param):
                        if inspect.isfunction(v) or (inspect.ismethod(v) and inspect.isfunction(v.__func__)):
                            worklist.append(v)
        else:
            # The obj is the user's function but in form of a class
            found_methods = []
            for k, v in linspect.getmembers_static(obj):
                if inspect.isfunction(v) or (inspect.ismethod(v) and inspect.isfunction(v.__func__)):
                    found_methods.append(k)
                    worklist.append(v)
            if "__call__" not in found_methods:
>               raise Exception('The class you passed as the function to '
                                'run must contain the "__call__" method')
E               Exception: The class you passed as the function to run must contain the "__call__" method

But it definitely does have a __call__ method:

print(dir(partial_f))

['__call__', '__class__', '__class_getitem__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__get__', '__getattribute__', '__getstate__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__setstate__', '__sizeof__', '__str__', '__subclasshook__', '__vectorcalloffset__', 'args', 'func', 'keywords']

I think this indicates that this line is not general enough

lithops/lithops/job/serialize.py

Line 158 in ceebd0f

if inspect.isfunction(v) or (inspect.ismethod(v) and inspect.isfunction(v.__func__)):

[TomNicholas]

I would be happy to open a PR to fix this if you agree that this is the issue.

[JosepSampe]

It's completely possible that there are unhandled use cases. Feel free to open a PR with a solution if you have one :)