Source code for wemake_python_styleguide.types

# -*- coding: utf-8 -*-

"""
This module contains knowledge about the most important types that we use.

There are also different :term:`visitor` specific types
that are defined and use exclusively in that file.

Policy
~~~~~~

If any of the following statements is true, move the type to this file:

- if type is used in multiple files
- if type is complex enough it has to be documented
- if type is very important for the public API

final
~~~~~

As you can see in the source code almost everything
is marked as ``@final`` or ``Final``.

It means that this value can not be subclassed or reassigned.
This it only a ``mypy`` feature, it does not affect ``python`` runtime.

We do this, because we value composition over inheritance.
And this ``@final`` decorators help you to define readable and clear APIs
for cases when inheritance is used.

See also:
    My guide about ``@final`` type in ``python``:
    https://sobolevn.me/2018/07/real-python-contants

Reference
~~~~~~~~~

"""

import ast
from typing import Tuple, Type, Union

from typing_extensions import Protocol, final

#: In cases we need to work with both import types.
AnyImport = Union[ast.Import, ast.ImportFrom]

#: In cases we need to work with both function definitions.
AnyFunctionDef = Union[ast.FunctionDef, ast.AsyncFunctionDef]

#: In cases we need to work with all function definitions (including lambdas).
AnyFunctionDefAndLambda = Union[AnyFunctionDef, ast.Lambda]

#: In cases we need to work with both forms of if functions.
AnyIf = Union[ast.If, ast.IfExp]

#: In cases we need to work with both sync and async loops.
AnyFor = Union[ast.For, ast.AsyncFor]

#: In cases we need to work with both sync and async context managers.
AnyWith = Union[ast.With, ast.AsyncWith]

#: Flake8 API format to return error messages.
CheckResult = Tuple[int, int, str, type]

#: Tuple of AST node types for declarative syntax.
AnyNodes = Tuple[Type[ast.AST], ...]

#: When we search for assign elements, we also need typed assign.
AnyAssign = Union[ast.Assign, ast.AnnAssign]

#: That's how we define context of operations.
ContextNodes = Union[
    ast.Module,
    ast.ClassDef,
    AnyFunctionDef,
]

#: In cases we need to work with both access types.
AnyAccess = Union[
    ast.Attribute,
    ast.Subscript,
]


@final
class ConfigurationOptions(Protocol):
    """
    Provides structure for the options we use in our checker and visitors.

    Then this protocol is passed to each individual visitor.
    It uses structural sub-typing, and does not represent any kind of a real
    class or structure.

    See also:
        https://mypy.readthedocs.io/en/latest/protocols.html

    """

    # General:
    min_name_length: int
    i_control_code: bool
    max_name_length: int

    # Complexity:
    max_arguments: int
    max_local_variables: int
    max_returns: int
    max_expressions: int
    max_module_members: int
    max_methods: int
    max_line_complexity: int
    max_jones_score: int
    max_imports: int
    max_imported_names: int
    max_base_classes: int
    max_decorators: int
    max_string_usages: int
    max_awaits: int
    max_try_body_length: int
    max_module_expressions: int
    max_function_expressions: int
    max_asserts: int
    max_access_level: int
    max_attributes: int