Incorrect re-definition of global variables

[tomMoral]

The global variable are not correctly handeled in the __main__ module as they do not remain global.

Script

from cloudpickle import dumps, loads


VARIABLE = "uninitialized"


def func1():
 global VARIABLE
 print("[func1] global var id{}: {}".format(id(VARIABLE), VARIABLE))
 VARIABLE = "initialized"
 return VARIABLE


# Dump and reload the function
reloaded_f1 = loads(dumps(func1))

# The function call does not change the value of the global VARIABLE
assert reloaded_f1() == "initialized"
print(VARIABLE)

# Changing the value of VARIABLE does not affect the function
VARIABLE = 'test'
assert reloaded_f1() == "initialized"

# But redumping it changes the value
assert loads(dumps(func1))() == "initialized"
print(VARIABLE)

Output

[func1] global var id140197480377584: uninitialized
uninitialized
[func1] global var id140197483839984: initialized
[func1] global var id140197480295592: test
test

I think a way to avoid this is to pass the global variable to _fill_function and use globals():

• If the global variable is already present in globals, do not do anything.
• If it is not present, add it with the given value.