Current File : //usr/lib/python3/dist-packages/mypy/plugins/default.py
from functools import partial
from typing import Callable, Optional, List
from mypy import message_registry
from mypy.nodes import StrExpr, IntExpr, DictExpr, UnaryExpr
from mypy.plugin import (
Plugin, FunctionContext, MethodContext, MethodSigContext, AttributeContext, ClassDefContext
)
from mypy.plugins.common import try_getting_str_literals
from mypy.types import (
FunctionLike, Type, Instance, AnyType, TypeOfAny, CallableType, NoneType, TypedDictType,
TypeVarType, TPDICT_FB_NAMES, get_proper_type, LiteralType, TupleType
)
from mypy.subtypes import is_subtype
from mypy.typeops import make_simplified_union
from mypy.checkexpr import is_literal_type_like
class DefaultPlugin(Plugin):
"""Type checker plugin that is enabled by default."""
def get_function_hook(self, fullname: str
) -> Optional[Callable[[FunctionContext], Type]]:
from mypy.plugins import ctypes, singledispatch
if fullname in ('contextlib.contextmanager', 'contextlib.asynccontextmanager'):
return contextmanager_callback
elif fullname == 'ctypes.Array':
return ctypes.array_constructor_callback
elif fullname == 'functools.singledispatch':
return singledispatch.create_singledispatch_function_callback
return None
def get_method_signature_hook(self, fullname: str
) -> Optional[Callable[[MethodSigContext], FunctionLike]]:
from mypy.plugins import ctypes, singledispatch
if fullname == 'typing.Mapping.get':
return typed_dict_get_signature_callback
elif fullname in set(n + '.setdefault' for n in TPDICT_FB_NAMES):
return typed_dict_setdefault_signature_callback
elif fullname in set(n + '.pop' for n in TPDICT_FB_NAMES):
return typed_dict_pop_signature_callback
elif fullname in set(n + '.update' for n in TPDICT_FB_NAMES):
return typed_dict_update_signature_callback
elif fullname == 'ctypes.Array.__setitem__':
return ctypes.array_setitem_callback
elif fullname == singledispatch.SINGLEDISPATCH_CALLABLE_CALL_METHOD:
return singledispatch.call_singledispatch_function_callback
return None
def get_method_hook(self, fullname: str
) -> Optional[Callable[[MethodContext], Type]]:
from mypy.plugins import ctypes, singledispatch
if fullname == 'typing.Mapping.get':
return typed_dict_get_callback
elif fullname == 'builtins.int.__pow__':
return int_pow_callback
elif fullname == 'builtins.int.__neg__':
return int_neg_callback
elif fullname in ('builtins.tuple.__mul__', 'builtins.tuple.__rmul__'):
return tuple_mul_callback
elif fullname in set(n + '.setdefault' for n in TPDICT_FB_NAMES):
return typed_dict_setdefault_callback
elif fullname in set(n + '.pop' for n in TPDICT_FB_NAMES):
return typed_dict_pop_callback
elif fullname in set(n + '.__delitem__' for n in TPDICT_FB_NAMES):
return typed_dict_delitem_callback
elif fullname == 'ctypes.Array.__getitem__':
return ctypes.array_getitem_callback
elif fullname == 'ctypes.Array.__iter__':
return ctypes.array_iter_callback
elif fullname == singledispatch.SINGLEDISPATCH_REGISTER_METHOD:
return singledispatch.singledispatch_register_callback
elif fullname == singledispatch.REGISTER_CALLABLE_CALL_METHOD:
return singledispatch.call_singledispatch_function_after_register_argument
return None
def get_attribute_hook(self, fullname: str
) -> Optional[Callable[[AttributeContext], Type]]:
from mypy.plugins import ctypes
from mypy.plugins import enums
if fullname == 'ctypes.Array.value':
return ctypes.array_value_callback
elif fullname == 'ctypes.Array.raw':
return ctypes.array_raw_callback
elif fullname in enums.ENUM_NAME_ACCESS:
return enums.enum_name_callback
elif fullname in enums.ENUM_VALUE_ACCESS:
return enums.enum_value_callback
return None
def get_class_decorator_hook(self, fullname: str
) -> Optional[Callable[[ClassDefContext], None]]:
from mypy.plugins import attrs
from mypy.plugins import dataclasses
from mypy.plugins import functools
if fullname in attrs.attr_class_makers:
return attrs.attr_class_maker_callback
elif fullname in attrs.attr_dataclass_makers:
return partial(
attrs.attr_class_maker_callback,
auto_attribs_default=True,
)
elif fullname in attrs.attr_frozen_makers:
return partial(
attrs.attr_class_maker_callback,
auto_attribs_default=None,
frozen_default=True,
)
elif fullname in attrs.attr_define_makers:
return partial(
attrs.attr_class_maker_callback,
auto_attribs_default=None,
)
elif fullname in dataclasses.dataclass_makers:
return dataclasses.dataclass_class_maker_callback
elif fullname in functools.functools_total_ordering_makers:
return functools.functools_total_ordering_maker_callback
return None
def contextmanager_callback(ctx: FunctionContext) -> Type:
"""Infer a better return type for 'contextlib.contextmanager'."""
# Be defensive, just in case.
if ctx.arg_types and len(ctx.arg_types[0]) == 1:
arg_type = get_proper_type(ctx.arg_types[0][0])
default_return = get_proper_type(ctx.default_return_type)
if (isinstance(arg_type, CallableType)
and isinstance(default_return, CallableType)):
# The stub signature doesn't preserve information about arguments so
# add them back here.
return default_return.copy_modified(
arg_types=arg_type.arg_types,
arg_kinds=arg_type.arg_kinds,
arg_names=arg_type.arg_names,
variables=arg_type.variables,
is_ellipsis_args=arg_type.is_ellipsis_args)
return ctx.default_return_type
def typed_dict_get_signature_callback(ctx: MethodSigContext) -> CallableType:
"""Try to infer a better signature type for TypedDict.get.
This is used to get better type context for the second argument that
depends on a TypedDict value type.
"""
signature = ctx.default_signature
if (isinstance(ctx.type, TypedDictType)
and len(ctx.args) == 2
and len(ctx.args[0]) == 1
and isinstance(ctx.args[0][0], StrExpr)
and len(signature.arg_types) == 2
and len(signature.variables) == 1
and len(ctx.args[1]) == 1):
key = ctx.args[0][0].value
value_type = get_proper_type(ctx.type.items.get(key))
ret_type = signature.ret_type
if value_type:
default_arg = ctx.args[1][0]
if (isinstance(value_type, TypedDictType)
and isinstance(default_arg, DictExpr)
and len(default_arg.items) == 0):
# Caller has empty dict {} as default for typed dict.
value_type = value_type.copy_modified(required_keys=set())
# Tweak the signature to include the value type as context. It's
# only needed for type inference since there's a union with a type
# variable that accepts everything.
tv = signature.variables[0]
assert isinstance(tv, TypeVarType)
return signature.copy_modified(
arg_types=[signature.arg_types[0],
make_simplified_union([value_type, tv])],
ret_type=ret_type)
return signature
def typed_dict_get_callback(ctx: MethodContext) -> Type:
"""Infer a precise return type for TypedDict.get with literal first argument."""
if (isinstance(ctx.type, TypedDictType)
and len(ctx.arg_types) >= 1
and len(ctx.arg_types[0]) == 1):
keys = try_getting_str_literals(ctx.args[0][0], ctx.arg_types[0][0])
if keys is None:
return ctx.default_return_type
output_types: List[Type] = []
for key in keys:
value_type = get_proper_type(ctx.type.items.get(key))
if value_type is None:
return ctx.default_return_type
if len(ctx.arg_types) == 1:
output_types.append(value_type)
elif (len(ctx.arg_types) == 2 and len(ctx.arg_types[1]) == 1
and len(ctx.args[1]) == 1):
default_arg = ctx.args[1][0]
if (isinstance(default_arg, DictExpr) and len(default_arg.items) == 0
and isinstance(value_type, TypedDictType)):
# Special case '{}' as the default for a typed dict type.
output_types.append(value_type.copy_modified(required_keys=set()))
else:
output_types.append(value_type)
output_types.append(ctx.arg_types[1][0])
if len(ctx.arg_types) == 1:
output_types.append(NoneType())
return make_simplified_union(output_types)
return ctx.default_return_type
def typed_dict_pop_signature_callback(ctx: MethodSigContext) -> CallableType:
"""Try to infer a better signature type for TypedDict.pop.
This is used to get better type context for the second argument that
depends on a TypedDict value type.
"""
signature = ctx.default_signature
str_type = ctx.api.named_generic_type('builtins.str', [])
if (isinstance(ctx.type, TypedDictType)
and len(ctx.args) == 2
and len(ctx.args[0]) == 1
and isinstance(ctx.args[0][0], StrExpr)
and len(signature.arg_types) == 2
and len(signature.variables) == 1
and len(ctx.args[1]) == 1):
key = ctx.args[0][0].value
value_type = ctx.type.items.get(key)
if value_type:
# Tweak the signature to include the value type as context. It's
# only needed for type inference since there's a union with a type
# variable that accepts everything.
tv = signature.variables[0]
assert isinstance(tv, TypeVarType)
typ = make_simplified_union([value_type, tv])
return signature.copy_modified(
arg_types=[str_type, typ],
ret_type=typ)
return signature.copy_modified(arg_types=[str_type, signature.arg_types[1]])
def typed_dict_pop_callback(ctx: MethodContext) -> Type:
"""Type check and infer a precise return type for TypedDict.pop."""
if (isinstance(ctx.type, TypedDictType)
and len(ctx.arg_types) >= 1
and len(ctx.arg_types[0]) == 1):
keys = try_getting_str_literals(ctx.args[0][0], ctx.arg_types[0][0])
if keys is None:
ctx.api.fail(message_registry.TYPEDDICT_KEY_MUST_BE_STRING_LITERAL, ctx.context)
return AnyType(TypeOfAny.from_error)
value_types = []
for key in keys:
if key in ctx.type.required_keys:
ctx.api.msg.typeddict_key_cannot_be_deleted(ctx.type, key, ctx.context)
value_type = ctx.type.items.get(key)
if value_type:
value_types.append(value_type)
else:
ctx.api.msg.typeddict_key_not_found(ctx.type, key, ctx.context)
return AnyType(TypeOfAny.from_error)
if len(ctx.args[1]) == 0:
return make_simplified_union(value_types)
elif (len(ctx.arg_types) == 2 and len(ctx.arg_types[1]) == 1
and len(ctx.args[1]) == 1):
return make_simplified_union([*value_types, ctx.arg_types[1][0]])
return ctx.default_return_type
def typed_dict_setdefault_signature_callback(ctx: MethodSigContext) -> CallableType:
"""Try to infer a better signature type for TypedDict.setdefault.
This is used to get better type context for the second argument that
depends on a TypedDict value type.
"""
signature = ctx.default_signature
str_type = ctx.api.named_generic_type('builtins.str', [])
if (isinstance(ctx.type, TypedDictType)
and len(ctx.args) == 2
and len(ctx.args[0]) == 1
and isinstance(ctx.args[0][0], StrExpr)
and len(signature.arg_types) == 2
and len(ctx.args[1]) == 1):
key = ctx.args[0][0].value
value_type = ctx.type.items.get(key)
if value_type:
return signature.copy_modified(arg_types=[str_type, value_type])
return signature.copy_modified(arg_types=[str_type, signature.arg_types[1]])
def typed_dict_setdefault_callback(ctx: MethodContext) -> Type:
"""Type check TypedDict.setdefault and infer a precise return type."""
if (isinstance(ctx.type, TypedDictType)
and len(ctx.arg_types) == 2
and len(ctx.arg_types[0]) == 1
and len(ctx.arg_types[1]) == 1):
keys = try_getting_str_literals(ctx.args[0][0], ctx.arg_types[0][0])
if keys is None:
ctx.api.fail(message_registry.TYPEDDICT_KEY_MUST_BE_STRING_LITERAL, ctx.context)
return AnyType(TypeOfAny.from_error)
default_type = ctx.arg_types[1][0]
value_types = []
for key in keys:
value_type = ctx.type.items.get(key)
if value_type is None:
ctx.api.msg.typeddict_key_not_found(ctx.type, key, ctx.context)
return AnyType(TypeOfAny.from_error)
# The signature_callback above can't always infer the right signature
# (e.g. when the expression is a variable that happens to be a Literal str)
# so we need to handle the check ourselves here and make sure the provided
# default can be assigned to all key-value pairs we're updating.
if not is_subtype(default_type, value_type):
ctx.api.msg.typeddict_setdefault_arguments_inconsistent(
default_type, value_type, ctx.context)
return AnyType(TypeOfAny.from_error)
value_types.append(value_type)
return make_simplified_union(value_types)
return ctx.default_return_type
def typed_dict_delitem_callback(ctx: MethodContext) -> Type:
"""Type check TypedDict.__delitem__."""
if (isinstance(ctx.type, TypedDictType)
and len(ctx.arg_types) == 1
and len(ctx.arg_types[0]) == 1):
keys = try_getting_str_literals(ctx.args[0][0], ctx.arg_types[0][0])
if keys is None:
ctx.api.fail(message_registry.TYPEDDICT_KEY_MUST_BE_STRING_LITERAL, ctx.context)
return AnyType(TypeOfAny.from_error)
for key in keys:
if key in ctx.type.required_keys:
ctx.api.msg.typeddict_key_cannot_be_deleted(ctx.type, key, ctx.context)
elif key not in ctx.type.items:
ctx.api.msg.typeddict_key_not_found(ctx.type, key, ctx.context)
return ctx.default_return_type
def typed_dict_update_signature_callback(ctx: MethodSigContext) -> CallableType:
"""Try to infer a better signature type for TypedDict.update."""
signature = ctx.default_signature
if (isinstance(ctx.type, TypedDictType)
and len(signature.arg_types) == 1):
arg_type = get_proper_type(signature.arg_types[0])
assert isinstance(arg_type, TypedDictType)
arg_type = arg_type.as_anonymous()
arg_type = arg_type.copy_modified(required_keys=set())
return signature.copy_modified(arg_types=[arg_type])
return signature
def int_pow_callback(ctx: MethodContext) -> Type:
"""Infer a more precise return type for int.__pow__."""
# int.__pow__ has an optional modulo argument,
# so we expect 2 argument positions
if (len(ctx.arg_types) == 2
and len(ctx.arg_types[0]) == 1 and len(ctx.arg_types[1]) == 0):
arg = ctx.args[0][0]
if isinstance(arg, IntExpr):
exponent = arg.value
elif isinstance(arg, UnaryExpr) and arg.op == '-' and isinstance(arg.expr, IntExpr):
exponent = -arg.expr.value
else:
# Right operand not an int literal or a negated literal -- give up.
return ctx.default_return_type
if exponent >= 0:
return ctx.api.named_generic_type('builtins.int', [])
else:
return ctx.api.named_generic_type('builtins.float', [])
return ctx.default_return_type
def int_neg_callback(ctx: MethodContext) -> Type:
"""Infer a more precise return type for int.__neg__.
This is mainly used to infer the return type as LiteralType
if the original underlying object is a LiteralType object
"""
if isinstance(ctx.type, Instance) and ctx.type.last_known_value is not None:
value = ctx.type.last_known_value.value
fallback = ctx.type.last_known_value.fallback
if isinstance(value, int):
if is_literal_type_like(ctx.api.type_context[-1]):
return LiteralType(value=-value, fallback=fallback)
else:
return ctx.type.copy_modified(last_known_value=LiteralType(
value=-value,
fallback=ctx.type,
line=ctx.type.line,
column=ctx.type.column,
))
elif isinstance(ctx.type, LiteralType):
value = ctx.type.value
fallback = ctx.type.fallback
if isinstance(value, int):
return LiteralType(value=-value, fallback=fallback)
return ctx.default_return_type
def tuple_mul_callback(ctx: MethodContext) -> Type:
"""Infer a more precise return type for tuple.__mul__ and tuple.__rmul__.
This is used to return a specific sized tuple if multiplied by Literal int
"""
if not isinstance(ctx.type, TupleType):
return ctx.default_return_type
arg_type = get_proper_type(ctx.arg_types[0][0])
if isinstance(arg_type, Instance) and arg_type.last_known_value is not None:
value = arg_type.last_known_value.value
if isinstance(value, int):
return ctx.type.copy_modified(items=ctx.type.items * value)
elif isinstance(ctx.type, LiteralType):
value = arg_type.value
if isinstance(value, int):
return ctx.type.copy_modified(items=ctx.type.items * value)
return ctx.default_return_type
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