测试Enum列表中的成员资格失败

Question

I'm trying to check if an Enum is in a list of Enums but it is not working as expected.

If I write the code in a single script and I run it, it works fine:

>>> from enum import Enum
>>> class X(Enum):
...   A = 'a'
...   B = 'b'
...   C = 'c'
...
>>> s = [X.A, X.B]
>>> x = X.C
>>> y = X.B
>>> x in s
False
>>> y in s
True

Yet, in my code, the test doesn't seem to work. This is what I added to debug the behavior:

print(type(node.action.kind), node.action.kind)
print(type(KINDS), type(KINDS[0]), KINDS)
if node.action.kind in KINDS:
    print('FIRST TEST')
elif node.action.kind.value in [i.value for i in KINDS]:
    print('SECOND TEST')
else:
    print('NOT IN KINDS')

I would expect it to print FIRST TEST when the condition matches yet the code prints SECOND TEST :

<enum 'ActionKind'> ActionKind.TALK
<class 'list'> <enum 'ActionKind'> [<ActionKind.CALL: 'api_call'>, <ActionKind.WAIT: 'wait'>, <ActionKind.HANGUP: 'hangup'>]
NOT IN KINDS

<enum 'ActionKind'> ActionKind.WAIT
<class 'list'> <enum 'ActionKind'> [<ActionKind.CALL: 'api_call'>, <ActionKind.WAIT: 'wait'>, <ActionKind.HANGUP: 'hangup'>]
SECOND TEST

I can't see any apparent difference other than the enum is defined elsewhere and the list of KINDS is populated from imported constants in another file. What is happening? Why can't I test membership in list of Enum with the in operator?

Answer 1

I found the cause of the problem. I still don't understand it but I will leave this here in case it helps anyone. The problem was that the enum was being reloaded. Once reloaded, even though the printout for print(type(node.action.kind).__module__ matched, the enums were not.

The following code is the minimal code that reproduces the error:

import mylib.classes
from mylib.classes import *
import mylib.renderer
from mylib.renderer import *

nodes = get_nodes() # from classes
check_nodes(nodes) # from renderer
from importlib import reload
reload(mylib.classes)
reload(mylib.renderer)
check_nodes(nodes) # from renderer

The first call to check_nodes works fine and FIRST TEST is printed. After reloading the modules it stops working and SECOND TEST is printed instead. This code is part of a script that runs in the background and reloads the code between iterations in order for changes to make effect. We only use this functionality during development.

If it helps, I am on Python 3.7.0 (default, Oct 2 2018, 09:19:48) [Clang 9.0.0 (clang-900.0.39.2)]