1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
flake8-import-order
===================
|Build Status|
A `flake8 <http://flake8.readthedocs.org/en/latest/>`__ and `Pylama
<https://github.com/klen/pylama>`__ plugin that checks the ordering of
your imports. It does not check anything else about the
imports. Merely that they are grouped and ordered correctly.
In general stdlib comes first, then 3rd party, then local packages,
and that each group is individually alphabetized, however this depends
on the style used. Flake8-Import-Order supports a number of `styles
<#styles>`_ and is extensible allowing for `custom styles
<#extending-styles>`_.
This plugin was originally developed to match the style preferences of
the `cryptography <https://github.com/pyca/cryptography>`__ project,
with this style remaining the default.
Warnings
--------
This package adds 4 new flake8 warnings
- ``I100``: Your import statements are in the wrong order.
- ``I101``: The names in your from import are in the wrong order.
- ``I201``: Missing newline between import groups.
- ``I202``: Additional newline in a group of imports.
Styles
------
The following styles are directly supported,
* ``cryptography`` - see an `example <https://github.com/PyCQA/flake8-import-order/blob/master/tests/test_cases/complete_cryptography.py>`__
* ``google`` - style described in `Google Style Guidelines <https://google.github.io/styleguide/pyguide.html?showone=Imports_formatting#Imports_formatting>`__, see an `example <https://github.com/PyCQA/flake8-import-order/blob/master/tests/test_cases/complete_google.py>`__
* ``smarkets`` - style as ``google`` only with `import` statements before `from X import ...` statements, see an `example <https://github.com/PyCQA/flake8-import-order/blob/master/tests/test_cases/complete_smarkets.py>`__
* ``appnexus`` - style as ``google`` only with `import` statements for packages local to your company or organisation coming after `import` statements for third-party packages, see an `example <https://github.com/PyCQA/flake8-import-order/blob/master/tests/test_cases/complete_appnexus.py>`__
* ``edited`` - see an `example <https://github.com/PyCQA/flake8-import-order/blob/master/tests/test_cases/complete_edited.py>`__
* ``pycharm`` - style as ``smarkets`` only with case sensitive sorting imported names
* ``pep8`` - style that only enforces groups without enforcing the order within the groups
You can also `add your own style <#extending-styles>`_ by extending ``Style``
class.
Configuration
-------------
You will want to set the ``application-import-names`` option to a
comma separated list of names that should be considered local to your
application. These will be used to help categorise your import
statements into the correct groups. Note that relative imports are
always considered local.
You will want to set the ``application-package-names`` option to a
comma separated list of names that should be considered local to your
company or organisation, but which are obtained using some sort of
package manager like Pip, Apt, or Yum. Typically, code representing
the values listed in this option is located in a different repository
than the code being developed. This option is only accepted in the
supported ``appnexus`` or ``edited`` styles or in any style that
accepts application package names.
The ``application-import-names`` and ``application-package-names`` can
contain namespaced packages or even exact nested module names. (This
is possible with 0.16 onwards).
``import-order-style`` controls what style the plugin follows
(``cryptography`` is the default).
Limitations
-----------
Currently these checks are limited to module scope imports only.
Conditional imports in module scope will also be ignored.
Classification of an imported module is achieved by checking the
module against a stdlib list and then if there is no match against the
``application-import-names`` list and ``application-package-names`` if
the style accepts application-package names. Only if none of these
lists contain the imported module will it be classified as third
party.
These checks only consider an import against its previous import,
rather than considering all the imports together. This means that
``I100`` errors are only raised for the latter of adjacent imports out
of order. For example,
.. code-block:: python
import X.B
import X # I100
import X.A
only ``import X`` raises an ``I100`` error, yet ``import X.A`` is also
out of order compared with the ``import X.B``.
Imported modules are classified as stdlib if the module is in a
vendored list of stdlib modules. This list is based on the latest
release of Python and hence the results can be misleading. This list
is also the same for all Python versions because otherwise it would
be impossible to write programs that work under both Python 2 and 3
*and* pass the import order check.
The ``I202`` check will consider any blank line between imports to
count, even if the line is not contextually related to the
imports. For example,
.. code-block:: python
import logging
try:
from logging import NullHandler
except ImportError:
class NullHandler(logging.Handler):
"""Shim for version of Python < 2.7."""
def emit(self, record):
pass
import sys # I202 due to the blank line before the 'def emit'
will trigger a ``I202`` error despite the blank line not being
contextually related.
Extending styles
----------------
You can add your own style by extending ``flake8_import_order.styles.Style``
class. Here's an example:
.. code-block:: python
from flake8_import_order.styles import Cryptography
class ReversedCryptography(Cryptography):
# Note that Cryptography is a subclass of Style.
@staticmethod
def sorted_names(names):
return reversed(Cryptography.sorted_names(names))
By default there are five import groupings or sections; future,
stdlib, third party, application, and relative imports. A style can
choose to accept another grouping, application-package, by setting the
``Style`` class variable ``accepts_application_package_names`` to
True, e.g.
.. code-block:: python
class PackageNameCryptography(Cryptography):
accepts_application_package_names = True
To make flake8-import-order able to discover your extended style, you need to
register it as ``flake8_import_order.styles`` using setuptools' `entry points
<https://setuptools.readthedocs.io/en/latest/pkg_resources.html#entry-points>`__
mechanism:
.. code-block:: python
# setup.py of your style package
setup(
name='flake8-import-order-reversed-cryptography',
...,
entry_points={
'flake8_import_order.styles': [
'reversed = reversedcryptography:ReversedCryptography',
# 'reversed' is a style name. You can pass it to
# --import-order-style option
# 'reversedcryptography:ReversedCryptography' is an import path
# of your extended style class.
]
}
)
.. |Build Status| image:: https://travis-ci.org/PyCQA/flake8-import-order.svg?branch=master
:target: https://travis-ci.org/PyCQA/flake8-import-order
|
