Naming

Naming is hard! It is in fact one of the two hardest problems.

These checks are required to make your application easier to read and understand by multiple people over the long period of time.

Note

Beautiful is better than ugly. Explicit is better than implicit. Simple is better than complex. Readability counts. Namespaces are one honking great idea – let’s do more of those!

Summary

WrongModuleNameViolation	Forbids to use blacklisted module names.
WrongModuleMagicNameViolation	Forbids to use any magic names except whitelisted ones.
TooShortModuleNameViolation	Forbids to use module name shorter than some breakpoint.
WrongModuleNameUnderscoresViolation	Forbids to use multiple underscores in a row in a module name.
WrongModuleNamePatternViolation	Forbids to use module names that do not match our pattern.
WrongVariableNameViolation	Forbids to have blacklisted variable names.
TooShortVariableNameViolation	Forbids to have too short variable names.
PrivateNameViolation	Forbids to have private name pattern.
SameAliasImportViolation	Forbids to use the same alias as the original name in imports.

Module names

class WrongModuleNameViolation(node=None, text=None)

Bases: wemake_python_styleguide.violations.base.SimpleViolation

Forbids to use blacklisted module names.

Reasoning:

Some module names are not expressive enough. It is hard to tell what you can find inside the utils.py module.

Solution:

Rename your module, reorganize the contents.

See BAD_MODULE_NAMES for the full list of bad module names.

Example:

# Correct:
github.py
views.py

# Wrong:
utils.py
helpers.py

Note

Returns Z100 as error code

class WrongModuleMagicNameViolation(node=None, text=None)

Bases: wemake_python_styleguide.violations.base.SimpleViolation

Forbids to use any magic names except whitelisted ones.

Reasoning:

Do not fall in love with magic. There’s no good reason to use magic names, when you can use regular names.

See MAGIC_MODULE_NAMES_WHITELIST for the full list of allowed magic module names.

Example:

# Correct:
__init__.py
__main__.py

# Wrong:
__version__.py

Note

Returns Z101 as error code

class TooShortModuleNameViolation(node=None, text=None)

Bases: wemake_python_styleguide.violations.base.SimpleViolation

Forbids to use module name shorter than some breakpoint.

Reasoning:

Too short module names are not expressive enough. We will have to open the code to find out what is going on there.

Solution:

Rename the module.

This rule is configurable with --min-module-name-length.

Note

Returns Z102 as error code

class WrongModuleNameUnderscoresViolation(node=None, text=None)

Bases: wemake_python_styleguide.violations.base.SimpleViolation

Forbids to use multiple underscores in a row in a module name.

Reasoning:

It is hard to tell how many underscores are there: two or three?

Solution:

Keep just one underscore in a module name.

Example:

# Correct:
__init__.py
some_module_name.py
test.py

# Wrong:
some__wrong__name.py
my__module.py
__fake__magic__.py

Note

Returns Z103 as error code

class WrongModuleNamePatternViolation(node=None, text=None)

Bases: wemake_python_styleguide.violations.base.SimpleViolation

Forbids to use module names that do not match our pattern.

Reasoning:

Just like the variable names - module names should be consistent. Ideally, they should follow the same rules. For python world it is common to use snake_case notation.

We use MODULE_NAME_PATTERN to validate the module names.

Example:

# Correct:
__init__.py
some_module_name.py
test12.py

# Wrong:
_some.py
MyModule.py
0001_migration.py

Note

Returns Z104 as error code

Variable names

class WrongVariableNameViolation(node, text=None)

Bases: wemake_python_styleguide.violations.base.ASTViolation

Forbids to have blacklisted variable names.

Reasoning:

We have found some names that are not expressive enough. However, they appear in the code more than offten. All names that we forbid to use could be improved.

Solution:

Try to use more specific name instead. If you really want to use any of the names from the list, add a prefix or suffix to it. It will serve you well.

See BAD_VARIABLE_NAMES for the full list of blacklisted variable names.

Example:

# Correct:
html_node_item = None

# Wrong:
item = None

Note

Returns Z110 as error code

class TooShortVariableNameViolation(node, text=None)

Bases: wemake_python_styleguide.violations.base.ASTViolation

Forbids to have too short variable names.

Reasoning:

It is hard to understand what the variable means and why it is used, if it’s name is too short.

Solution:

Think of another name. Give more context to it.

This rule is configurable with --min-variable-length.

Example:

# Correct:
x_coordinate = 1
abscissa = 2

# Wrong:
x = 1
y = 2

Note

Returns Z111 as error code

class PrivateNameViolation(node, text=None)

Bases: wemake_python_styleguide.violations.base.ASTViolation

Forbids to have private name pattern.

Reasoning:

Private is not private in python. So, why should we pretend it is? This might lead to some serious design flaws.

Solution:

Rename your variable or method to be protected. Think about your design, why do you want to make it private? Are there any other ways to achieve what you want?

This rule checks: variables, attributes, functions, and methods.

Example:

# Correct:
def _collect_coverage(self): ...

# Wrong:
def __collect_coverage(self): ...

Note

Returns Z112 as error code

class SameAliasImportViolation(node, text=None)

Bases: wemake_python_styleguide.violations.base.ASTViolation

Forbids to use the same alias as the original name in imports.

Reasoning:

Why would you even do this in the first place?

Example:

# Correct:
from os import path

# Wrong:
from os import path as path

Note

Returns Z113 as error code

class WrongModuleNameViolation(node=None, text=None)

Bases: wemake_python_styleguide.violations.base.SimpleViolation

Forbids to use blacklisted module names.

Reasoning:

Some module names are not expressive enough. It is hard to tell what you can find inside the utils.py module.

Solution:

Rename your module, reorganize the contents.

See BAD_MODULE_NAMES for the full list of bad module names.

Example:

# Correct:
github.py
views.py

# Wrong:
utils.py
helpers.py

Note

Returns Z100 as error code

error_template = 'Found wrong module name'

Error message shown to the user.

class WrongModuleMagicNameViolation(node=None, text=None)

Bases: wemake_python_styleguide.violations.base.SimpleViolation

Forbids to use any magic names except whitelisted ones.

Reasoning:

Do not fall in love with magic. There’s no good reason to use magic names, when you can use regular names.

See MAGIC_MODULE_NAMES_WHITELIST for the full list of allowed magic module names.

Example:

# Correct:
__init__.py
__main__.py

# Wrong:
__version__.py

Note

Returns Z101 as error code

error_template = 'Found wrong module magic name'

Error message shown to the user.

class TooShortModuleNameViolation(node=None, text=None)

Bases: wemake_python_styleguide.violations.base.SimpleViolation

Forbids to use module name shorter than some breakpoint.

Reasoning:

Too short module names are not expressive enough. We will have to open the code to find out what is going on there.

Solution:

Rename the module.

This rule is configurable with --min-module-name-length.

Note

Returns Z102 as error code

error_template = 'Found too short module name'

Error message shown to the user.

class WrongModuleNameUnderscoresViolation(node=None, text=None)

Bases: wemake_python_styleguide.violations.base.SimpleViolation

Forbids to use multiple underscores in a row in a module name.

Reasoning:

It is hard to tell how many underscores are there: two or three?

Solution:

Keep just one underscore in a module name.

Example:

# Correct:
__init__.py
some_module_name.py
test.py

# Wrong:
some__wrong__name.py
my__module.py
__fake__magic__.py

Note

Returns Z103 as error code

error_template = 'Found repeating underscores in a module name'

Error message shown to the user.

class WrongModuleNamePatternViolation(node=None, text=None)

Bases: wemake_python_styleguide.violations.base.SimpleViolation

Forbids to use module names that do not match our pattern.

Reasoning:

Just like the variable names - module names should be consistent. Ideally, they should follow the same rules. For python world it is common to use snake_case notation.

We use MODULE_NAME_PATTERN to validate the module names.

Example:

# Correct:
__init__.py
some_module_name.py
test12.py

# Wrong:
_some.py
MyModule.py
0001_migration.py

Note

Returns Z104 as error code

error_template = 'Found incorrect module name pattern'

Error message shown to the user.

class WrongVariableNameViolation(node, text=None)

Bases: wemake_python_styleguide.violations.base.ASTViolation

Forbids to have blacklisted variable names.

Reasoning:

We have found some names that are not expressive enough. However, they appear in the code more than offten. All names that we forbid to use could be improved.

Solution:

Try to use more specific name instead. If you really want to use any of the names from the list, add a prefix or suffix to it. It will serve you well.

See BAD_VARIABLE_NAMES for the full list of blacklisted variable names.

Example:

# Correct:
html_node_item = None

# Wrong:
item = None

Note

Returns Z110 as error code

error_template = 'Found wrong variable name "{0}"'

Error message shown to the user.

class TooShortVariableNameViolation(node, text=None)

Bases: wemake_python_styleguide.violations.base.ASTViolation

Forbids to have too short variable names.

Reasoning:

It is hard to understand what the variable means and why it is used, if it’s name is too short.

Solution:

Think of another name. Give more context to it.

This rule is configurable with --min-variable-length.

Example:

# Correct:
x_coordinate = 1
abscissa = 2

# Wrong:
x = 1
y = 2

Note

Returns Z111 as error code

error_template = 'Found too short name "{0}"'

Error message shown to the user.

class PrivateNameViolation(node, text=None)

Bases: wemake_python_styleguide.violations.base.ASTViolation

Forbids to have private name pattern.

Reasoning:

Private is not private in python. So, why should we pretend it is? This might lead to some serious design flaws.

Solution:

Rename your variable or method to be protected. Think about your design, why do you want to make it private? Are there any other ways to achieve what you want?

This rule checks: variables, attributes, functions, and methods.

Example:

# Correct:
def _collect_coverage(self): ...

# Wrong:
def __collect_coverage(self): ...

Note

Returns Z112 as error code

error_template = 'Found private name pattern "{0}"'

Error message shown to the user.

class SameAliasImportViolation(node, text=None)

Bases: wemake_python_styleguide.violations.base.ASTViolation

Forbids to use the same alias as the original name in imports.

Reasoning:

Why would you even do this in the first place?

Example:

# Correct:
from os import path

# Wrong:
from os import path as path

Note

Returns Z113 as error code

error_template = 'Found same alias import "{0}"'

Error message shown to the user.