Python 尝试在顶级包之外进行相对导入
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Attempted relative import beyond toplevel package
提问by Mr_and_Mrs_D
Here is my folder structure:
这是我的文件夹结构：
Mopy/ # no init.py !
bash/
__init__.py
bash.py # <--- Edit: yep there is such a module too
bass.py
bosh/
__init__.py # contains from .. import bass
bsa_files.py
...
test_bash\
__init__.py # code below
test_bosh\
__init__.py
test_bsa_files.py
In test_bash\__init__.pyI have:
在test_bash\__init__.py我有：
import sys
from os.path import dirname, abspath, join, sep
mopy = dirname(dirname(abspath(__file__)))
assert mopy.split(sep)[-1].lower() == 'mopy'
sys.path.append(mopy)
print 'Mopy folder appended to path: ', mopy
while in test_bsa_files.py:
而在test_bsa_files.py：
import unittest
from unittest import TestCase
import bosh
class TestBSAHeader(TestCase):
def test_read_header(self):
bosh.bsa_files.Header.read_header()
if __name__ == '__main__':
unittest.main()
Now when I issue:
现在当我发出：
python.exe "C:\_\JetBrains\PyCharm 2016.2.2\helpers\pycharm\utrunner.py" C:\path\to\Mopy\test_bash\test_bosh\test_bsa_files.py true
I get:
我得到：
Traceback (most recent call last):
File "C:\_\JetBrains\PyCharm 2016.2.2\helpers\pycharm\utrunner.py", line 124, in <module>
modules = [loadSource(a[0])]
File "C:\_\JetBrains\PyCharm 2016.2.2\helpers\pycharm\utrunner.py", line 43, in loadSource
module = imp.load_source(moduleName, fileName)
File "C:\Dropbox\eclipse_workspaces\python\wrye-bash\Mopy\test_bash\test_bosh\test_bsa_files.py", line 4, in <module>
import bosh
File "C:\Dropbox\eclipse_workspaces\python\wrye-bash\Mopy\bash\bosh\__init__.py", line 50, in <module>
from .. import bass
ValueError: Attempted relative import beyond toplevel package
Since 'Mopy" is in the sys.path and bosh\__init__.pyis correctly resolved why it complains about relative import above the top level package ? Which is the top level package?
由于“Mopy”在 sys.path 中并且bosh\__init__.py已正确解决，为什么它会抱怨顶级包上方的相对导入？哪个是顶级包？
Incidentally this is my attempt to add tests to a legacy project - had asked in Python test package layoutbut was closed as a duplicate of Where do the Python unit tests go?. Comments on my current test package layout are much appreciated !
顺便说一句，这是我尝试向遗留项目添加测试 - 曾在Python 测试包布局中询问过，但作为Python 单元测试去哪里的副本而关闭？. 非常感谢对我当前测试包布局的评论！
Well the answer belowdoes not work in my case:
The modulebash.py is the entry point to the application containing:
该模块bash.py是入口点到包含应用：
if __name__ == '__main__':
main()
When I use import bash.boshor from bash import boshI get:
当我使用import bash.bosh或from bash import bosh我得到：
C:\_\Python27\python.exe "C:\_\JetBrains\PyCharm 2016.2.2\helpers\pycharm\utrunner.py" C:\Dropbox\eclipse_workspaces\python\wrye-bash\Mopy\test_bash\test_bosh\test_bsa_files.py true
Testing started at 3:45 PM ...
usage: utrunner.py [-h] [-o OBLIVIONPATH] [-p PERSONALPATH] [-u USERPATH]
[-l LOCALAPPDATAPATH] [-b] [-r] [-f FILENAME] [-q] [-i]
[-I] [-g GAMENAME] [-d] [-C] [-P] [--no-uac] [--uac]
[--bashmon] [-L LANGUAGE]
utrunner.py: error: unrecognized arguments: C:\Dropbox\eclipse_workspaces\python\wrye-bash\Mopy\test_bash\test_bosh\test_bsa_files.py true
Process finished with exit code 2
This usage message is from the main() in bash.
此用法消息来自 bash 中的 main()。
回答by MisterMiyagi
TLDR: Do
TLDR：做
import bash.bosh
or
或者
from bash import bosh
If you also just happen to have a construct like bash.bash, you have to make sure your package takes precedence over its contents. Instead of appending, add it to the front of the search order:
如果您碰巧也有类似 的构造bash.bash，则必须确保您的包优先于其内容。而不是追加，将其添加到搜索顺序的前面：
# test_bash\__init__.py
sys.path.insert(0, mopy)
When you do
当你做
import bosh
it will import the modulebosh. This means Mopy/bashis in your sys.path, python finds the file boshthere, and imports it. The module is now globally known by the name bosh. Whether boshis itself a module or package doesn't matter for this, it only changes whether bosh.pyor bosh/__init__.pyis used.
它将导入模块bosh。这意味着Mopy/bash在您的sys.path, python 中找到该文件bosh，然后将其导入。该模块现在以名称而闻名bosh。无论bosh是本身就是一个模块或包不要紧此，它只会改变是否bosh.py或bosh/__init__.py使用。
Now, when boshtries to do
现在，当bosh试图做
from .. import bass
this is nota file system operation ("one directory up, file bass") but a module name operation. It means "one package level up, module bass". boshwasn't imported from its package, but on its own, though. So going up one package is not possible - you end up at the package '', which is not valid.
这不是一个文件系统操作（“一个目录，文件bass”）而是一个模块名称操作。它的意思是“一包升级，模块低音”。bosh不是从它的包中导入的，而是它自己导入的。所以上升一个包裹是不可能的——你最终''得到的是无效的包裹。
Let's look at what happens when you do
让我们看看当你这样做时会发生什么
import bash.bosh
instead. First, the packagebashis imported. Then, boshis imported as a module of that package- it is globally know as bash.bosh, even if you used from bash import bosh.
反而。首先，导入包bash。然后，bosh作为该包的模块导入-bash.bosh即使您使用from bash import bosh.
When boshdoes
什么bosh时候
from .. import bass
that one works now: going one level up from bash.boshgets you to bash. From there, bassis imported as bash.bass.
那个现在有效：从上一层开始bash.bosh让你到bash. 从那里，bass作为bash.bass.
See also this related answerfor executing a module from within a package without modifying sys.path.
另请参阅此相关答案以从包内执行模块而不修改sys.path。
