Current File : //usr/lib/python3/dist-packages/mypy/plugins/functools.py
"""Plugin for supporting the functools standard library module."""
from typing import Dict, NamedTuple, Optional
from typing_extensions import Final
import mypy.plugin
from mypy.nodes import ARG_POS, ARG_STAR2, Argument, FuncItem, Var
from mypy.plugins.common import add_method_to_class
from mypy.types import AnyType, CallableType, get_proper_type, Type, TypeOfAny, UnboundType
functools_total_ordering_makers: Final = {
'functools.total_ordering',
}
_ORDERING_METHODS: Final = {
'__lt__',
'__le__',
'__gt__',
'__ge__',
}
_MethodInfo = NamedTuple('_MethodInfo', [('is_static', bool), ('type', CallableType)])
def functools_total_ordering_maker_callback(ctx: mypy.plugin.ClassDefContext,
auto_attribs_default: bool = False) -> None:
"""Add dunder methods to classes decorated with functools.total_ordering."""
if ctx.api.options.python_version < (3,):
# This plugin is not supported in Python 2 mode (it's a no-op).
return
comparison_methods = _analyze_class(ctx)
if not comparison_methods:
ctx.api.fail(
'No ordering operation defined when using "functools.total_ordering": < > <= >=',
ctx.reason)
return
# prefer __lt__ to __le__ to __gt__ to __ge__
root = max(comparison_methods, key=lambda k: (comparison_methods[k] is None, k))
root_method = comparison_methods[root]
if not root_method:
# None of the defined comparison methods can be analysed
return
other_type = _find_other_type(root_method)
bool_type = ctx.api.named_type('builtins.bool')
ret_type: Type = bool_type
if root_method.type.ret_type != ctx.api.named_type('builtins.bool'):
proper_ret_type = get_proper_type(root_method.type.ret_type)
if not (isinstance(proper_ret_type, UnboundType)
and proper_ret_type.name.split('.')[-1] == 'bool'):
ret_type = AnyType(TypeOfAny.implementation_artifact)
for additional_op in _ORDERING_METHODS:
# Either the method is not implemented
# or has an unknown signature that we can now extrapolate.
if not comparison_methods.get(additional_op):
args = [Argument(Var('other', other_type), other_type, None, ARG_POS)]
add_method_to_class(ctx.api, ctx.cls, additional_op, args, ret_type)
def _find_other_type(method: _MethodInfo) -> Type:
"""Find the type of the ``other`` argument in a comparison method."""
first_arg_pos = 0 if method.is_static else 1
cur_pos_arg = 0
other_arg = None
for arg_kind, arg_type in zip(method.type.arg_kinds, method.type.arg_types):
if arg_kind.is_positional():
if cur_pos_arg == first_arg_pos:
other_arg = arg_type
break
cur_pos_arg += 1
elif arg_kind != ARG_STAR2:
other_arg = arg_type
break
if other_arg is None:
return AnyType(TypeOfAny.implementation_artifact)
return other_arg
def _analyze_class(ctx: mypy.plugin.ClassDefContext) -> Dict[str, Optional[_MethodInfo]]:
"""Analyze the class body, its parents, and return the comparison methods found."""
# Traverse the MRO and collect ordering methods.
comparison_methods: Dict[str, Optional[_MethodInfo]] = {}
# Skip object because total_ordering does not use methods from object
for cls in ctx.cls.info.mro[:-1]:
for name in _ORDERING_METHODS:
if name in cls.names and name not in comparison_methods:
node = cls.names[name].node
if isinstance(node, FuncItem) and isinstance(node.type, CallableType):
comparison_methods[name] = _MethodInfo(node.is_static, node.type)
continue
if isinstance(node, Var):
proper_type = get_proper_type(node.type)
if isinstance(proper_type, CallableType):
comparison_methods[name] = _MethodInfo(node.is_staticmethod, proper_type)
continue
comparison_methods[name] = None
return comparison_methods
Mini Shell