循环导入从 pylint 修复 R0401答案

【问题标题】：Cyclic Imports to fix R0401 from pylint循环导入从 pylint 修复 R0401
【发布时间】：2019-02-16 17:10:07
【问题描述】：

Pylint 抱怨 NLTK 包的特定文件的循环导入错误代码为 R0401，例如

nltk/nltk/ccg/lexicon.py:1: [R0401(cyclic-import), ] Cyclic import (nltk -> nltk.internals)
nltk/nltk/ccg/lexicon.py:1: [R0401(cyclic-import), ] Cyclic import (nltk.corpus -> nltk.tokenize -> nltk.tokenize.punkt -> nltk.probability)
nltk/nltk/ccg/lexicon.py:1: [R0401(cyclic-import), ] Cyclic import (nltk.corpus -> nltk.tokenize -> nltk.tokenize.texttiling)
nltk/nltk/ccg/lexicon.py:1: [R0401(cyclic-import), ] Cyclic import (nltk.draw.tree -> nltk.tree)
nltk/nltk/ccg/lexicon.py:1: [R0401(cyclic-import), ] Cyclic import (nltk.tree -> nltk.treeprettyprinter)
nltk/nltk/ccg/lexicon.py:1: [R0401(cyclic-import), ] Cyclic import (nltk.grammar -> nltk.parse.pchart)
nltk/nltk/ccg/lexicon.py:1: [R0401(cyclic-import), ] Cyclic import (nltk.stem -> nltk.stem.porter)
nltk/nltk/ccg/lexicon.py:1: [R0401(cyclic-import), ] Cyclic import (nltk.classify.maxent -> nltk.classify.tadm)

完整名单在https://github.com/nltk/nltk/issues/2113

但是看看进口：

from __future__ import unicode_literals from 

import re
from collections import defaultdict

from nltk.ccg.api import PrimitiveCategory, Direction, CCGVar, FunctionalCategory
from nltk.compat import python_2_unicode_compatible
from nltk.internals import deprecated

from nltk.sem.logic import *

但是看看 nltk.internals https://github.com/nltk/nltk/blob/develop/nltk/internals.py ，没有任何指向 nltk.ccg.lexicon 的循环导入：

from __future__ import print_function

import subprocess
import os
import fnmatch
import re
import warnings
import textwrap
import types
import sys
import stat
import locale

# Use the c version of ElementTree, which is faster, if possible:
try:
    from xml.etree import cElementTree as ElementTree
except ImportError:
    from xml.etree import ElementTree

from six import string_types

from nltk import __file__
from nltk import compat

R0401(cyclic-import) 消息是什么意思？

查看nltk.ccg.lexicon.py 和nltk.internals.py 没有任何循环导入，那么如何解决问题。

【问题讨论】：

标签： python nltk pylint cyclic-dependency

【解决方案1】：

不知道为什么 pylint 在 nltk/nltk/ccg/lexicon.py 文件中报告这些，但循环导入本身可以在错误消息的右侧看到。

取第一个错误：Cyclic import (nltk -> nltk.internals)：根__init__.py有一个来自nltk.internals的导入，而internals.py有一个来自包根的导入，这显然是一个循环导入。

【讨论】：