Source code for wemake_python_styleguide.violations.consistency
# -*- coding: utf-8 -*-
"""
These checks limit the Python's inconsistency.
We can do the same things differently in Python.
For example, there are three ways to format a string.
There are several ways to write the same number.
We like our code to be consistent.
It is easier to bare with your code base if you follow these rules.
Note:
Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
.. currentmodule:: wemake_python_styleguide.violations.consistency
Summary
-------
.. autosummary::
:nosignatures:
LocalFolderImportViolation
DottedRawImportViolation
UnicodeStringViolation
UnderscoredNumberViolation
PartialFloatViolation
FormattedStringViolation
RequiredBaseClassViolation
MultipleIfsInComprehensionViolation
Consistency checks
------------------
.. autoclass:: LocalFolderImportViolation
.. autoclass:: DottedRawImportViolation
.. autoclass:: UnicodeStringViolation
.. autoclass:: UnderscoredNumberViolation
.. autoclass:: PartialFloatViolation
.. autoclass:: FormattedStringViolation
.. autoclass:: RequiredBaseClassViolation
.. autoclass:: MultipleIfsInComprehensionViolation
"""
from wemake_python_styleguide.violations.base import (
ASTViolation,
TokenizeViolation,
)
[docs]class LocalFolderImportViolation(ASTViolation):
"""
Forbids to have imports relative to the current folder.
Reasoning:
We should pick one style and stick to it.
We have decided to use the explicit one.
Example::
# Correct:
from my_package.version import get_version
# Wrong:
from .version import get_version
from ..drivers import MySQLDriver
Note:
Returns Z300 as error code
"""
#: Error message shown to the user.
error_template = 'Found local folder import "{0}"'
code = 300
[docs]class DottedRawImportViolation(ASTViolation):
"""
Forbids to use imports like ``import os.path``.
Reasoning:
There too many different ways to import something.
We should pick one style and stick to it.
We have decided to use the readable one.
Solution:
Refactor your import statement.
Example::
# Correct:
from os import path
# Wrong:
import os.path
Note:
Returns Z301 as error code
"""
#: Error message shown to the user.
error_template = 'Found dotted raw import "{0}"'
code = 301
[docs]class UnicodeStringViolation(TokenizeViolation):
"""
Forbids to use ``u`` string prefix.
Reasoning:
We do not need this prefix since ``python2``.
But, it is still possible to find it inside the codebase.
Solution:
Remove this prefix.
Example::
# Correct:
nickname = 'sobolevn'
file_contents = b'aabbcc'
# Wrong:
nickname = u'sobolevn'
Note:
Returns Z302 as error code
"""
code = 302
#: Error message shown to the user.
error_template = 'Found unicode string prefix: {0}'
[docs]class UnderscoredNumberViolation(TokenizeViolation):
"""
Forbids to use underscores (``_``) in numbers.
Reasoning:
It is possible to write ``1000`` in three different ways:
``1_000``, ``10_00``, and ``100_0``.
And it would be still the same number.
Count how many ways there are to write bigger numbers.
Currently, it all depends on cultural habits of the author.
We enforce a single way to write numbers: without the underscore.
Solution:
Numbers should be written as numbers: ``1000``.
If you have a very big number with a lot of zeros, use multiplication.
Example::
# Correct:
phone = 88313443
million = 1000000
# Wrong:
phone = 8_83_134_43
million = 100_00_00
Note:
Returns Z303 as error code
"""
code = 303
#: Error message shown to the user.
error_template = 'Found underscored number: {0}'
[docs]class PartialFloatViolation(TokenizeViolation):
"""
Forbids to use partial floats like ``.05`` or ``23.``.
Reasoning:
Partial numbers are hard to read and they can be confused with
other numbers. For example, it is really
easy to confuse ``0.5`` and ``.05`` when reading
through the source code.
Solution:
Use full versions with leading and starting zeros.
Example::
# Correct:
half = 0.5
ten_float = 10.0
# Wrong:
half = .5
ten_float = 10.
Note:
Returns Z304 as error code
"""
code = 304
#: Error message shown to the user.
error_template = 'Found partial float: {0}'
[docs]class RequiredBaseClassViolation(ASTViolation):
"""
Forbids to write classes without base classes.
Reasoning:
We just need to decide how to do it.
We need a single and unified rule about base classes.
We have decided to stick to the explicit base class notation.
Solution:
Add a base class.
Example::
# Correct:
class Some(object): ...
# Wrong:
class Some: ...
Note:
Returns Z306 as error code
"""
#: Error message shown to the user.
error_template = 'Found class without a base class "{0}"'
code = 306
[docs]class MultipleIfsInComprehensionViolation(ASTViolation):
"""
Forbids to have multiple ``if`` statements inside list comprehensions.
Reasoning:
It is very hard to read multiple ``if`` statements inside
a list comprehension. Since, it is even hard to tell all of them
should pass or fail.
Solution:
Use a single ``if`` statement inside list comprehensions.
Use ``filter()`` if you have complicated logic.
Example::
# Wrong:
nodes = [node for node in html if node != 'b' if node != 'i']
# Correct:
nodes = [node for node in html if node not in ('b', 'i')]
Note:
Returns Z307 as error code
"""
should_use_text = False
#: Error message shown to the user.
error_template = 'Found list comprehension with multiple `if`s'
code = 307