def analyze_member_var_access(name: str, itype: Instance, info: TypeInfo,
mx: MemberContext) -> Type:
"""Analyse attribute access that does not target a method.
This is logically part of analyze_member_access and the arguments are similar.
original_type is the type of E in the expression E.var
"""
# It was not a method. Try looking up a variable.
v = lookup_member_var_or_accessor(info, name, mx.is_lvalue)
vv = v
if isinstance(vv, Decorator):
# The associated Var node of a decorator contains the type.
v = vv.var
if isinstance(vv, TypeInfo):
# If the associated variable is a TypeInfo synthesize a Var node for
# the purposes of type checking. This enables us to type check things
# like accessing class attributes on an inner class.
v = Var(name, type=type_object_type(vv, mx.builtin_type))
v.info = info
if isinstance(vv, TypeAlias) and isinstance(get_proper_type(vv.target),
Instance):
# Similar to the above TypeInfo case, we allow using
# qualified type aliases in runtime context if it refers to an
# instance type. For example:
# class C:
# A = List[int]
# x = C.A() <- this is OK
typ = instance_alias_type(vv, mx.builtin_type)
v = Var(name, type=typ)
v.info = info
if isinstance(v, Var):
implicit = info[name].implicit
# An assignment to final attribute is always an error,
# independently of types.
if mx.is_lvalue and not mx.chk.get_final_context():
check_final_member(name, info, mx.msg, mx.context)
return analyze_var(name, v, itype, info, mx, implicit=implicit)
elif isinstance(v, FuncDef):
assert False, "Did not expect a function"
elif (not v
and name not in ['__getattr__', '__setattr__', '__getattribute__']
and not mx.is_operator):
if not mx.is_lvalue:
for method_name in ('__getattribute__', '__getattr__'):
method = info.get_method(method_name)
# __getattribute__ is defined on builtins.object and returns Any, so without
# the guard this search will always find object.__getattribute__ and conclude
# that the attribute exists
if method and method.info.fullname != 'builtins.object':
function = function_type(
method, mx.builtin_type('builtins.function'))
bound_method = bind_self(function, mx.self_type)
typ = map_instance_to_supertype(itype, method.info)
getattr_type = get_proper_type(
expand_type_by_instance(bound_method, typ))
if isinstance(getattr_type, CallableType):
result = getattr_type.ret_type
# Call the attribute hook before returning.
fullname = '{}.{}'.format(method.info.fullname, name)
hook = mx.chk.plugin.get_attribute_hook(fullname)
if hook:
result = hook(
AttributeContext(
get_proper_type(mx.original_type), result,
mx.context, mx.chk))
return result
else:
setattr_meth = info.get_method('__setattr__')
if setattr_meth and setattr_meth.info.fullname != 'builtins.object':
setattr_func = function_type(
setattr_meth, mx.builtin_type('builtins.function'))
bound_type = bind_self(setattr_func, mx.self_type)
typ = map_instance_to_supertype(itype, setattr_meth.info)
setattr_type = get_proper_type(
expand_type_by_instance(bound_type, typ))
if isinstance(
setattr_type,
CallableType) and len(setattr_type.arg_types) > 0:
return setattr_type.arg_types[-1]
if itype.type.fallback_to_any:
return AnyType(TypeOfAny.special_form)
# Could not find the member.
if mx.is_super:
mx.msg.undefined_in_superclass(name, mx.context)
return AnyType(TypeOfAny.from_error)
else:
if mx.chk and mx.chk.should_suppress_optional_error([itype]):
return AnyType(TypeOfAny.from_error)
return mx.msg.has_no_attr(mx.original_type, itype, name, mx.context,
mx.module_symbol_table)
def visit_type_var(self, t: TypeVarType) -> Type:
return AnyType(TypeOfAny.special_form)
def analyze_member_access(name: str,
typ: Type,
node: Context,
is_lvalue: bool,
is_super: bool,
is_operator: bool,
builtin_type: Callable[[str], Instance],
not_ready_callback: Callable[[str, Context], None],
msg: MessageBuilder,
*,
original_type: Type,
chk: 'mypy.checker.TypeChecker',
override_info: Optional[TypeInfo] = None) -> Type:
"""Return the type of attribute `name` of typ.
This is a general operation that supports various different variations:
1. lvalue or non-lvalue access (i.e. setter or getter access)
2. supertype access (when using super(); is_super == True and
override_info should refer to the supertype)
original_type is the most precise inferred or declared type of the base object
that we have available. typ is generally a supertype of original_type.
When looking for an attribute of typ, we may perform recursive calls targeting
the fallback type, for example.
original_type is always the type used in the initial call.
"""
# TODO: this and following functions share some logic with subtypes.find_member,
# consider refactoring.
if isinstance(typ, Instance):
if name == '__init__' and not is_super:
# Accessing __init__ in statically typed code would compromise
# type safety unless used via super().
msg.fail(messages.CANNOT_ACCESS_INIT, node)
return AnyType(TypeOfAny.from_error)
# The base object has an instance type.
info = typ.type
if override_info:
info = override_info
if (experiments.find_occurrences
and info.name() == experiments.find_occurrences[0]
and name == experiments.find_occurrences[1]):
msg.note(
"Occurrence of '{}.{}'".format(*experiments.find_occurrences),
node)
# Look up the member. First look up the method dictionary.
method = info.get_method(name)
if method:
if method.is_property:
assert isinstance(method, OverloadedFuncDef)
first_item = cast(Decorator, method.items[0])
return analyze_var(name,
first_item.var,
typ,
info,
node,
is_lvalue,
msg,
original_type,
not_ready_callback,
chk=chk)
if is_lvalue:
msg.cant_assign_to_method(node)
signature = function_type(method,
builtin_type('builtins.function'))
signature = freshen_function_type_vars(signature)
if name == '__new__':
# __new__ is special and behaves like a static method -- don't strip
# the first argument.
pass
else:
signature = bind_self(signature, original_type)
typ = map_instance_to_supertype(typ, method.info)
member_type = expand_type_by_instance(signature, typ)
freeze_type_vars(member_type)
return member_type
else:
# Not a method.
return analyze_member_var_access(name,
typ,
info,
node,
is_lvalue,
is_super,
builtin_type,
not_ready_callback,
msg,
original_type=original_type,
chk=chk)
elif isinstance(typ, AnyType):
# The base object has dynamic type.
return AnyType(TypeOfAny.from_another_any, source_any=typ)
elif isinstance(typ, NoneTyp):
if chk.should_suppress_optional_error([typ]):
return AnyType(TypeOfAny.from_error)
# The only attribute NoneType has are those it inherits from object
return analyze_member_access(name,
builtin_type('builtins.object'),
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
original_type=original_type,
chk=chk)
elif isinstance(typ, UnionType):
# The base object has dynamic type.
msg.disable_type_names += 1
results = [
analyze_member_access(name,
subtype,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
original_type=original_type,
chk=chk) for subtype in typ.relevant_items()
]
msg.disable_type_names -= 1
return UnionType.make_simplified_union(results)
elif isinstance(typ, TupleType):
# Actually look up from the fallback instance type.
return analyze_member_access(name,
typ.fallback,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
original_type=original_type,
chk=chk)
elif isinstance(typ, TypedDictType):
# Actually look up from the fallback instance type.
return analyze_member_access(name,
typ.fallback,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
original_type=original_type,
chk=chk)
elif isinstance(typ, FunctionLike) and typ.is_type_obj():
# Class attribute.
# TODO super?
ret_type = typ.items()[0].ret_type
if isinstance(ret_type, TupleType):
ret_type = ret_type.fallback
if isinstance(ret_type, Instance):
if not is_operator:
# When Python sees an operator (eg `3 == 4`), it automatically translates that
# into something like `int.__eq__(3, 4)` instead of `(3).__eq__(4)` as an
# optimization.
#
# While it normally it doesn't matter which of the two versions are used, it
# does cause inconsistencies when working with classes. For example, translating
# `int == int` to `int.__eq__(int)` would not work since `int.__eq__` is meant to
# compare two int _instances_. What we really want is `type(int).__eq__`, which
# is meant to compare two types or classes.
#
# This check makes sure that when we encounter an operator, we skip looking up
# the corresponding method in the current instance to avoid this edge case.
# See https://github.com/python/mypy/pull/1787 for more info.
result = analyze_class_attribute_access(
ret_type,
name,
node,
is_lvalue,
builtin_type,
not_ready_callback,
msg,
original_type=original_type)
if result:
return result
# Look up from the 'type' type.
return analyze_member_access(name,
typ.fallback,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
original_type=original_type,
chk=chk)
else:
assert False, 'Unexpected type {}'.format(repr(ret_type))
elif isinstance(typ, FunctionLike):
# Look up from the 'function' type.
return analyze_member_access(name,
typ.fallback,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
original_type=original_type,
chk=chk)
elif isinstance(typ, TypeVarType):
return analyze_member_access(name,
typ.upper_bound,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
original_type=original_type,
chk=chk)
elif isinstance(typ, DeletedType):
msg.deleted_as_rvalue(typ, node)
return AnyType(TypeOfAny.from_error)
elif isinstance(typ, TypeType):
# Similar to FunctionLike + is_type_obj() above.
item = None
if isinstance(typ.item, Instance):
item = typ.item
elif isinstance(typ.item, AnyType):
fallback = builtin_type('builtins.type')
ignore_messages = msg.copy()
ignore_messages.disable_errors()
return analyze_member_access(name,
fallback,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
ignore_messages,
original_type=original_type,
chk=chk)
elif isinstance(typ.item, TypeVarType):
if isinstance(typ.item.upper_bound, Instance):
item = typ.item.upper_bound
if item and not is_operator:
# See comment above for why operators are skipped
result = analyze_class_attribute_access(
item,
name,
node,
is_lvalue,
builtin_type,
not_ready_callback,
msg,
original_type=original_type)
if result:
return result
fallback = builtin_type('builtins.type')
if item is not None:
fallback = item.type.metaclass_type or fallback
return analyze_member_access(name,
fallback,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
original_type=original_type,
chk=chk)
if chk.should_suppress_optional_error([typ]):
return AnyType(TypeOfAny.from_error)
return msg.has_no_attr(original_type, typ, name, node)
def build_namedtuple_typeinfo(
self, name: str, items: List[str], types: List[Type],
default_items: Mapping[str, Expression]) -> TypeInfo:
strtype = self.api.named_type('__builtins__.str')
implicit_any = AnyType(TypeOfAny.special_form)
basetuple_type = self.api.named_type('__builtins__.tuple',
[implicit_any])
dictype = (self.api.named_type_or_none('builtins.dict',
[strtype, implicit_any])
or self.api.named_type('__builtins__.object'))
# Actual signature should return OrderedDict[str, Union[types]]
ordereddictype = (self.api.named_type_or_none('builtins.dict',
[strtype, implicit_any])
or self.api.named_type('__builtins__.object'))
fallback = self.api.named_type('__builtins__.tuple', [implicit_any])
# Note: actual signature should accept an invariant version of Iterable[UnionType[types]].
# but it can't be expressed. 'new' and 'len' should be callable types.
iterable_type = self.api.named_type_or_none('typing.Iterable',
[implicit_any])
function_type = self.api.named_type('__builtins__.function')
info = self.api.basic_new_typeinfo(name, fallback)
info.is_named_tuple = True
tuple_base = TupleType(types, fallback)
info.tuple_type = tuple_base
# We can't calculate the complete fallback type until after semantic
# analysis, since otherwise base classes might be incomplete. Postpone a
# callback function that patches the fallback.
self.api.schedule_patch(PRIORITY_FALLBACKS,
lambda: calculate_tuple_fallback(tuple_base))
def add_field(var: Var,
is_initialized_in_class: bool = False,
is_property: bool = False) -> None:
var.info = info
var.is_initialized_in_class = is_initialized_in_class
var.is_property = is_property
var._fullname = '%s.%s' % (info.fullname(), var.name())
info.names[var.name()] = SymbolTableNode(MDEF, var)
vars = [Var(item, typ) for item, typ in zip(items, types)]
for var in vars:
add_field(var, is_property=True)
tuple_of_strings = TupleType([strtype for _ in items], basetuple_type)
add_field(Var('_fields', tuple_of_strings),
is_initialized_in_class=True)
add_field(Var('_field_types', dictype), is_initialized_in_class=True)
add_field(Var('_field_defaults', dictype),
is_initialized_in_class=True)
add_field(Var('_source', strtype), is_initialized_in_class=True)
add_field(Var('__annotations__', ordereddictype),
is_initialized_in_class=True)
add_field(Var('__doc__', strtype), is_initialized_in_class=True)
tvd = TypeVarDef(SELF_TVAR_NAME,
info.fullname() + '.' + SELF_TVAR_NAME, -1, [],
info.tuple_type)
selftype = TypeVarType(tvd)
def add_method(
funcname: str,
ret: Type,
args: List[Argument],
is_classmethod: bool = False,
is_new: bool = False,
) -> None:
if is_classmethod or is_new:
first = [
Argument(Var('_cls'), TypeType.make_normalized(selftype),
None, ARG_POS)
]
else:
first = [Argument(Var('_self'), selftype, None, ARG_POS)]
args = first + args
types = [arg.type_annotation for arg in args]
items = [arg.variable.name() for arg in args]
arg_kinds = [arg.kind for arg in args]
assert None not in types
signature = CallableType(cast(List[Type], types), arg_kinds, items,
ret, function_type)
signature.variables = [tvd]
func = FuncDef(funcname, args, Block([]))
func.info = info
func.is_class = is_classmethod
func.type = set_callable_name(signature, func)
func._fullname = info.fullname() + '.' + funcname
if is_classmethod:
v = Var(funcname, func.type)
v.is_classmethod = True
v.info = info
v._fullname = func._fullname
func.is_decorated = True
dec = Decorator(func, [NameExpr('classmethod')], v)
info.names[funcname] = SymbolTableNode(MDEF, dec)
else:
info.names[funcname] = SymbolTableNode(MDEF, func)
add_method('_replace',
ret=selftype,
args=[
Argument(var, var.type, EllipsisExpr(), ARG_NAMED_OPT)
for var in vars
])
def make_init_arg(var: Var) -> Argument:
default = default_items.get(var.name(), None)
kind = ARG_POS if default is None else ARG_OPT
return Argument(var, var.type, default, kind)
add_method('__new__',
ret=selftype,
args=[make_init_arg(var) for var in vars],
is_new=True)
add_method('_asdict', args=[], ret=ordereddictype)
special_form_any = AnyType(TypeOfAny.special_form)
add_method('_make',
ret=selftype,
is_classmethod=True,
args=[
Argument(Var('iterable', iterable_type), iterable_type,
None, ARG_POS),
Argument(Var('new'), special_form_any, EllipsisExpr(),
ARG_NAMED_OPT),
Argument(Var('len'), special_form_any, EllipsisExpr(),
ARG_NAMED_OPT)
])
self_tvar_expr = TypeVarExpr(SELF_TVAR_NAME,
info.fullname() + '.' + SELF_TVAR_NAME,
[], info.tuple_type)
info.names[SELF_TVAR_NAME] = SymbolTableNode(MDEF, self_tvar_expr)
return info
def fill_descriptor_types_for_related_field(
ctx: FunctionContext, django_context: DjangoContext) -> MypyType:
current_field = _get_current_field_from_assignment(ctx, django_context)
if current_field is None:
return AnyType(TypeOfAny.from_error)
assert isinstance(current_field, RelatedField)
related_model_cls = django_context.get_field_related_model_cls(
current_field)
if related_model_cls is None:
return AnyType(TypeOfAny.from_error)
default_related_field_type = set_descriptor_types_for_field(ctx)
# self reference with abstract=True on the model where ForeignKey is defined
current_model_cls = current_field.model
if current_model_cls._meta.abstract and current_model_cls == related_model_cls:
# for all derived non-abstract classes, set variable with this name to
# __get__/__set__ of ForeignKey of derived model
for model_cls in django_context.all_registered_model_classes:
if issubclass(model_cls,
current_model_cls) and not model_cls._meta.abstract:
derived_model_info = helpers.lookup_class_typeinfo(
helpers.get_typechecker_api(ctx), model_cls)
if derived_model_info is not None:
fk_ref_type = Instance(derived_model_info, [])
derived_fk_type = reparametrize_related_field_type(
default_related_field_type,
set_type=fk_ref_type,
get_type=fk_ref_type)
helpers.add_new_sym_for_info(derived_model_info,
name=current_field.name,
sym_type=derived_fk_type)
related_model = related_model_cls
related_model_to_set = related_model_cls
if related_model_to_set._meta.proxy_for_model is not None:
related_model_to_set = related_model_to_set._meta.proxy_for_model
typechecker_api = helpers.get_typechecker_api(ctx)
related_model_info = helpers.lookup_class_typeinfo(typechecker_api,
related_model)
if related_model_info is None:
# maybe no type stub
related_model_type = AnyType(TypeOfAny.unannotated)
else:
related_model_type = Instance(related_model_info, []) # type: ignore
related_model_to_set_info = helpers.lookup_class_typeinfo(
typechecker_api, related_model_to_set)
if related_model_to_set_info is None:
# maybe no type stub
related_model_to_set_type = AnyType(TypeOfAny.unannotated)
else:
related_model_to_set_type = Instance(related_model_to_set_info,
[]) # type: ignore
# replace Any with referred_to_type
return reparametrize_related_field_type(default_related_field_type,
set_type=related_model_to_set_type,
get_type=related_model_type)
def visit_type_list(self, t: TypeList) -> Type:
self.fail('Invalid type', t)
return AnyType()
def visit_unbound_type(self, t: UnboundType) -> Type:
sym = self.lookup(t.name, t)
if sym is not None:
fullname = sym.node.fullname()
if sym.kind == BOUND_TVAR:
if len(t.args) > 0:
self.fail(
'Type variable "{}" used with arguments'.format(
t.name), t)
tvar_expr = cast(TypeVarExpr, sym.node)
return TypeVarType(t.name, sym.tvar_id, tvar_expr.values,
self.builtin_type('builtins.object'),
tvar_expr.variance, t.line)
elif fullname == 'builtins.None':
return Void()
elif fullname == 'typing.Any':
return AnyType()
elif fullname == 'typing.Tuple':
if len(t.args) == 2 and isinstance(t.args[1], EllipsisType):
# Tuple[T, ...] (uniform, variable-length tuple)
node = self.lookup_fqn_func('builtins.tuple')
info = cast(TypeInfo, node.node)
return Instance(info, [t.args[0].accept(self)], t.line)
return TupleType(self.anal_array(t.args),
self.builtin_type('builtins.tuple'))
elif fullname == 'typing.Union':
items = self.anal_array(t.args)
items = [item for item in items if not isinstance(item, Void)]
return UnionType.make_union(items)
elif fullname == 'typing.Optional':
if len(t.args) != 1:
self.fail(
'Optional[...] must have exactly one type argument', t)
items = self.anal_array(t.args)
# Currently Optional[t] is just an alias for t.
return items[0]
elif fullname == 'typing.Callable':
return self.analyze_callable_type(t)
elif sym.kind == TYPE_ALIAS:
# TODO: Generic type aliases.
return sym.type_override
elif not isinstance(sym.node, TypeInfo):
name = sym.fullname
if name is None:
name = sym.node.name()
if isinstance(sym.node, Var) and isinstance(
sym.node.type, AnyType):
# Something with an Any type -- make it an alias for Any in a type
# context. This is slightly problematic as it allows using the type 'Any'
# as a base class -- however, this will fail soon at runtime so the problem
# is pretty minor.
return AnyType()
self.fail('Invalid type "{}"'.format(name), t)
return t
info = cast(TypeInfo, sym.node)
if len(t.args) > 0 and info.fullname() == 'builtins.tuple':
return TupleType(self.anal_array(t.args),
Instance(info, [AnyType()], t.line), t.line)
else:
# Analyze arguments and construct Instance type. The
# number of type arguments and their values are
# checked only later, since we do not always know the
# valid count at this point. Thus we may construct an
# Instance with an invalid number of type arguments.
instance = Instance(info, self.anal_array(t.args), t.line)
if info.tuple_type is None:
return instance
else:
# The class has a Tuple[...] base class so it will be
# represented as a tuple type.
if t.args:
self.fail('Generic tuple types not supported', t)
return AnyType()
return TupleType(self.anal_array(info.tuple_type.items),
fallback=instance,
line=t.line)
else:
return t
def test_any(self):
assert_equal(str(AnyType()), 'Any')
def test_generic_unbound_type(self):
u = UnboundType('Foo', [UnboundType('T'), AnyType()])
assert_equal(str(u), 'Foo?[T?, Any]')
def type_object_type(info: TypeInfo,
builtin_type: Callable[[str], Instance]) -> ProperType:
"""Return the type of a type object.
For a generic type G with type variables T and S the type is generally of form
Callable[..., G[T, S]]
where ... are argument types for the __init__/__new__ method (without the self
argument). Also, the fallback type will be 'type' instead of 'function'.
"""
# We take the type from whichever of __init__ and __new__ is first
# in the MRO, preferring __init__ if there is a tie.
init_method = info.get('__init__')
new_method = info.get('__new__')
if not init_method or not is_valid_constructor(init_method.node):
# Must be an invalid class definition.
return AnyType(TypeOfAny.from_error)
# There *should* always be a __new__ method except the test stubs
# lack it, so just copy init_method in that situation
new_method = new_method or init_method
if not is_valid_constructor(new_method.node):
# Must be an invalid class definition.
return AnyType(TypeOfAny.from_error)
# The two is_valid_constructor() checks ensure this.
assert isinstance(new_method.node, (SYMBOL_FUNCBASE_TYPES, Decorator))
assert isinstance(init_method.node, (SYMBOL_FUNCBASE_TYPES, Decorator))
init_index = info.mro.index(init_method.node.info)
new_index = info.mro.index(new_method.node.info)
fallback = info.metaclass_type or builtin_type('builtins.type')
if init_index < new_index:
method = init_method.node # type: Union[FuncBase, Decorator]
is_new = False
elif init_index > new_index:
method = new_method.node
is_new = True
else:
if init_method.node.info.fullname == 'builtins.object':
# Both are defined by object. But if we've got a bogus
# base class, we can't know for sure, so check for that.
if info.fallback_to_any:
# Construct a universal callable as the prototype.
any_type = AnyType(TypeOfAny.special_form)
sig = CallableType(arg_types=[any_type, any_type],
arg_kinds=[ARG_STAR, ARG_STAR2],
arg_names=["_args", "_kwds"],
ret_type=any_type,
fallback=builtin_type('builtins.function'))
return class_callable(sig, info, fallback, None, is_new=False)
# Otherwise prefer __init__ in a tie. It isn't clear that this
# is the right thing, but __new__ caused problems with
# typeshed (#5647).
method = init_method.node
is_new = False
# Construct callable type based on signature of __init__. Adjust
# return type and insert type arguments.
if isinstance(method, FuncBase):
t = function_type(method, fallback)
else:
assert isinstance(method.type, ProperType)
assert isinstance(method.type,
FunctionLike) # is_valid_constructor() ensures this
t = method.type
return type_object_type_from_function(t, info, method.info, fallback,
is_new)
def relationship_hook(ctx: FunctionContext) -> Type:
"""Support basic use cases for relationships.
Examples:
from sqlalchemy.orm import relationship
from one import OneModel
if TYPE_CHECKING:
from other import OtherModel
class User(Base):
__tablename__ = 'users'
id = Column(Integer(), primary_key=True)
one = relationship(OneModel)
other = relationship("OtherModel")
This also tries to infer the type argument for 'RelationshipProperty'
using the 'uselist' flag.
"""
assert isinstance(ctx.default_return_type, Instance) # type: ignore[misc]
original_type_arg = ctx.default_return_type.args[0]
has_annotation = not isinstance(get_proper_type(original_type_arg),
UninhabitedType)
arg = get_argument_by_name(ctx, "argument")
arg_type = get_proper_type(get_argtype_by_name(ctx, "argument"))
uselist_arg = get_argument_by_name(ctx, "uselist")
if isinstance(arg, StrExpr):
name = arg.value
sym = None # type: Optional[SymbolTableNode]
try:
# Private API for local lookup, but probably needs to be public.
sym = ctx.api.lookup_qualified(name) # type: ignore
except (KeyError, AssertionError):
pass
if sym and isinstance(sym.node, TypeInfo):
new_arg = fill_typevars_with_any(sym.node) # type: Type
else:
ctx.api.fail('Cannot find model "{}"'.format(name), ctx.context)
# TODO: Add note() to public API.
ctx.api.note(
"Only imported models can be found;" # type: ignore
' use "if TYPE_CHECKING: ..." to avoid import cycles',
ctx.context,
)
new_arg = AnyType(TypeOfAny.from_error)
else:
if isinstance(arg_type, CallableType) and arg_type.is_type_obj():
new_arg = fill_typevars_with_any(arg_type.type_object())
else:
# Something complex, stay silent for now.
new_arg = AnyType(TypeOfAny.special_form)
# We figured out, the model type. Now check if we need to wrap it in Iterable
if uselist_arg:
if parse_bool(uselist_arg):
new_arg = ctx.api.named_generic_type("typing.Iterable", [new_arg])
else:
if has_annotation:
# If there is an annotation we use it as a source of truth.
# This will cause false negatives, but it is better than lots of false positives.
new_arg = original_type_arg
return Instance(
ctx.default_return_type.type,
[new_arg],
line=ctx.default_return_type.line,
column=ctx.default_return_type.column,
)
def analyze_class_attribute_access(
itype: Instance,
name: str,
mx: MemberContext,
override_info: Optional[TypeInfo] = None,
original_vars: Optional[List[TypeVarDef]] = None) -> Optional[Type]:
"""Analyze access to an attribute on a class object.
itype is the return type of the class object callable, original_type is the type
of E in the expression E.var, original_vars are type variables of the class callable
(for generic classes).
"""
info = itype.type
if override_info:
info = override_info
node = info.get(name)
if not node:
if info.fallback_to_any:
return AnyType(TypeOfAny.special_form)
return None
is_decorated = isinstance(node.node, Decorator)
is_method = is_decorated or isinstance(node.node, FuncBase)
if mx.is_lvalue:
if is_method:
mx.msg.cant_assign_to_method(mx.context)
if isinstance(node.node, TypeInfo):
mx.msg.fail(message_registry.CANNOT_ASSIGN_TO_TYPE, mx.context)
# If a final attribute was declared on `self` in `__init__`, then it
# can't be accessed on the class object.
if node.implicit and isinstance(node.node, Var) and node.node.is_final:
mx.msg.fail(
message_registry.CANNOT_ACCESS_FINAL_INSTANCE_ATTR.format(
node.node.name), mx.context)
# An assignment to final attribute on class object is also always an error,
# independently of types.
if mx.is_lvalue and not mx.chk.get_final_context():
check_final_member(name, info, mx.msg, mx.context)
if info.is_enum and not (mx.is_lvalue or is_decorated or is_method):
enum_literal = LiteralType(name, fallback=itype)
# When we analyze enums, the corresponding Instance is always considered to be erased
# due to how the signature of Enum.__new__ is `(cls: Type[_T], value: object) -> _T`
# in typeshed. However, this is really more of an implementation detail of how Enums
# are typed, and we really don't want to treat every single Enum value as if it were
# from type variable substitution. So we reset the 'erased' field here.
return itype.copy_modified(erased=False, last_known_value=enum_literal)
t = node.type
if t:
if isinstance(t, PartialType):
symnode = node.node
assert isinstance(symnode, Var)
return mx.chk.handle_partial_var_type(t, mx.is_lvalue, symnode,
mx.context)
# Find the class where method/variable was defined.
if isinstance(node.node, Decorator):
super_info = node.node.var.info # type: Optional[TypeInfo]
elif isinstance(node.node, (Var, SYMBOL_FUNCBASE_TYPES)):
super_info = node.node.info
else:
super_info = None
# Map the type to how it would look as a defining class. For example:
# class C(Generic[T]): ...
# class D(C[Tuple[T, S]]): ...
# D[int, str].method()
# Here itype is D[int, str], isuper is C[Tuple[int, str]].
if not super_info:
isuper = None
else:
isuper = map_instance_to_supertype(itype, super_info)
if isinstance(node.node, Var):
assert isuper is not None
# Check if original variable type has type variables. For example:
# class C(Generic[T]):
# x: T
# C.x # Error, ambiguous access
# C[int].x # Also an error, since C[int] is same as C at runtime
if isinstance(t, TypeVarType) or has_type_vars(t):
# Exception: access on Type[...], including first argument of class methods is OK.
if not isinstance(get_proper_type(mx.original_type),
TypeType) or node.implicit:
if node.node.is_classvar:
message = message_registry.GENERIC_CLASS_VAR_ACCESS
else:
message = message_registry.GENERIC_INSTANCE_VAR_CLASS_ACCESS
mx.msg.fail(message, mx.context)
# Erase non-mapped variables, but keep mapped ones, even if there is an error.
# In the above example this means that we infer following types:
# C.x -> Any
# C[int].x -> int
t = erase_typevars(expand_type_by_instance(t, isuper))
is_classmethod = (
(is_decorated and cast(Decorator, node.node).func.is_class)
or (isinstance(node.node, FuncBase) and node.node.is_class))
t = get_proper_type(t)
if isinstance(t, FunctionLike) and is_classmethod:
t = check_self_arg(t, mx.self_type, False, mx.context, name,
mx.msg)
result = add_class_tvars(t,
itype,
isuper,
is_classmethod,
mx.builtin_type,
mx.self_type,
original_vars=original_vars)
if not mx.is_lvalue:
result = analyze_descriptor_access(mx.original_type,
result,
mx.builtin_type,
mx.msg,
mx.context,
chk=mx.chk)
return result
elif isinstance(node.node, Var):
mx.not_ready_callback(name, mx.context)
return AnyType(TypeOfAny.special_form)
if isinstance(node.node, TypeVarExpr):
mx.msg.fail(
message_registry.CANNOT_USE_TYPEVAR_AS_EXPRESSION.format(
info.name, name), mx.context)
return AnyType(TypeOfAny.from_error)
if isinstance(node.node, TypeInfo):
return type_object_type(node.node, mx.builtin_type)
if isinstance(node.node, MypyFile):
# Reference to a module object.
return mx.builtin_type('types.ModuleType')
if (isinstance(node.node, TypeAlias)
and isinstance(get_proper_type(node.node.target), Instance)):
return instance_alias_type(node.node, mx.builtin_type)
if is_decorated:
assert isinstance(node.node, Decorator)
if node.node.type:
return node.node.type
else:
mx.not_ready_callback(name, mx.context)
return AnyType(TypeOfAny.from_error)
else:
assert isinstance(node.node, FuncBase)
typ = function_type(node.node, mx.builtin_type('builtins.function'))
# Note: if we are accessing class method on class object, the cls argument is bound.
# Annotated and/or explicit class methods go through other code paths above, for
# unannotated implicit class methods we do this here.
if node.node.is_class:
typ = bind_self(typ, is_classmethod=True)
return typ
def analyze_var(name: str,
var: Var,
itype: Instance,
info: TypeInfo,
mx: MemberContext,
*,
implicit: bool = False) -> Type:
"""Analyze access to an attribute via a Var node.
This is conceptually part of analyze_member_access and the arguments are similar.
itype is the class object in which var is defined
original_type is the type of E in the expression E.var
if implicit is True, the original Var was created as an assignment to self
"""
# Found a member variable.
itype = map_instance_to_supertype(itype, var.info)
typ = var.type
if typ:
if isinstance(typ, PartialType):
return mx.chk.handle_partial_var_type(typ, mx.is_lvalue, var,
mx.context)
if mx.is_lvalue and var.is_property and not var.is_settable_property:
# TODO allow setting attributes in subclass (although it is probably an error)
mx.msg.read_only_property(name, itype.type, mx.context)
if mx.is_lvalue and var.is_classvar:
mx.msg.cant_assign_to_classvar(name, mx.context)
t = get_proper_type(expand_type_by_instance(typ, itype))
result = t # type: Type
typ = get_proper_type(typ)
if var.is_initialized_in_class and isinstance(
typ, FunctionLike) and not typ.is_type_obj():
if mx.is_lvalue:
if var.is_property:
if not var.is_settable_property:
mx.msg.read_only_property(name, itype.type, mx.context)
else:
mx.msg.cant_assign_to_method(mx.context)
if not var.is_staticmethod:
# Class-level function objects and classmethods become bound methods:
# the former to the instance, the latter to the class.
functype = typ
# Use meet to narrow original_type to the dispatched type.
# For example, assume
# * A.f: Callable[[A1], None] where A1 <: A (maybe A1 == A)
# * B.f: Callable[[B1], None] where B1 <: B (maybe B1 == B)
# * x: Union[A1, B1]
# In `x.f`, when checking `x` against A1 we assume x is compatible with A
# and similarly for B1 when checking agains B
dispatched_type = meet.meet_types(mx.original_type, itype)
signature = freshen_function_type_vars(functype)
signature = check_self_arg(signature, dispatched_type,
var.is_classmethod, mx.context,
name, mx.msg)
signature = bind_self(signature, mx.self_type,
var.is_classmethod)
expanded_signature = get_proper_type(
expand_type_by_instance(signature, itype))
if var.is_property:
# A property cannot have an overloaded type => the cast is fine.
assert isinstance(expanded_signature, CallableType)
result = expanded_signature.ret_type
else:
result = expanded_signature
else:
if not var.is_ready:
mx.not_ready_callback(var.name, mx.context)
# Implicit 'Any' type.
result = AnyType(TypeOfAny.special_form)
fullname = '{}.{}'.format(var.info.fullname, name)
hook = mx.chk.plugin.get_attribute_hook(fullname)
if result and not mx.is_lvalue and not implicit:
result = analyze_descriptor_access(mx.original_type,
result,
mx.builtin_type,
mx.msg,
mx.context,
chk=mx.chk)
if hook:
result = hook(
AttributeContext(get_proper_type(mx.original_type), result,
mx.context, mx.chk))
return result
def analyze_descriptor_access(instance_type: Type, descriptor_type: Type,
builtin_type: Callable[[str], Instance],
msg: MessageBuilder, context: Context, *,
chk: 'mypy.checker.TypeChecker') -> Type:
"""Type check descriptor access.
Arguments:
instance_type: The type of the instance on which the descriptor
attribute is being accessed (the type of ``a`` in ``a.f`` when
``f`` is a descriptor).
descriptor_type: The type of the descriptor attribute being accessed
(the type of ``f`` in ``a.f`` when ``f`` is a descriptor).
context: The node defining the context of this inference.
Return:
The return type of the appropriate ``__get__`` overload for the descriptor.
"""
instance_type = get_proper_type(instance_type)
descriptor_type = get_proper_type(descriptor_type)
if isinstance(descriptor_type, UnionType):
# Map the access over union types
return make_simplified_union([
analyze_descriptor_access(instance_type,
typ,
builtin_type,
msg,
context,
chk=chk) for typ in descriptor_type.items
])
elif not isinstance(descriptor_type, Instance):
return descriptor_type
if not descriptor_type.type.has_readable_member('__get__'):
return descriptor_type
dunder_get = descriptor_type.type.get_method('__get__')
if dunder_get is None:
msg.fail(
message_registry.DESCRIPTOR_GET_NOT_CALLABLE.format(
descriptor_type), context)
return AnyType(TypeOfAny.from_error)
function = function_type(dunder_get, builtin_type('builtins.function'))
bound_method = bind_self(function, descriptor_type)
typ = map_instance_to_supertype(descriptor_type, dunder_get.info)
dunder_get_type = expand_type_by_instance(bound_method, typ)
if isinstance(instance_type, FunctionLike) and instance_type.is_type_obj():
owner_type = instance_type.items()[0].ret_type
instance_type = NoneType()
elif isinstance(instance_type, TypeType):
owner_type = instance_type.item
instance_type = NoneType()
else:
owner_type = instance_type
_, inferred_dunder_get_type = chk.expr_checker.check_call(
dunder_get_type, [
TempNode(instance_type, context=context),
TempNode(TypeType.make_normalized(owner_type), context=context)
], [ARG_POS, ARG_POS], context)
inferred_dunder_get_type = get_proper_type(inferred_dunder_get_type)
if isinstance(inferred_dunder_get_type, AnyType):
# check_call failed, and will have reported an error
return inferred_dunder_get_type
if not isinstance(inferred_dunder_get_type, CallableType):
msg.fail(
message_registry.DESCRIPTOR_GET_NOT_CALLABLE.format(
descriptor_type), context)
return AnyType(TypeOfAny.from_error)
return inferred_dunder_get_type.ret_type
def visit_unbound_type(self, t: UnboundType) -> ProperType:
return AnyType(TypeOfAny.special_form)
def test_tuple_type(self):
assert_equal(str(TupleType([], None)), 'Tuple[]')
assert_equal(str(TupleType([self.x], None)), 'Tuple[X?]')
assert_equal(str(TupleType([self.x, AnyType()], None)), 'Tuple[X?, Any]')
def visit_unbound_type(self, t: UnboundType) -> Type:
return AnyType()
def visit_raw_str(self, s: str) -> Type:
# An escape hatch that allows the AST walker in fastparse2 to
# directly hook into the Python 3.5 type converter in some cases
# without needing to create an intermediary `ast3.Str` object.
return (parse_type_comment(s.strip(), self.line, self.errors)
or AnyType(TypeOfAny.from_error))
def visit_ellipsis_type(self, t: EllipsisType) -> Type:
self.fail("Unexpected '...'", t)
return AnyType()
def generic_visit(self, node: ast3.AST) -> Type: # type: ignore
self.fail(TYPE_COMMENT_AST_ERROR, self.line,
getattr(node, 'col_offset', -1))
return AnyType(TypeOfAny.from_error)
def parse_namedtuple_args(
self, call: CallExpr, fullname: str
) -> Optional[Tuple[List[str], List[Type], List[Expression], bool]]:
"""Parse a namedtuple() call into data needed to construct a type.
Returns a 4-tuple:
- List of argument names
- List of argument types
- Number of arguments that have a default value
- Whether the definition typechecked.
Return None if at least one of the types is not ready.
"""
# TODO: Share code with check_argument_count in checkexpr.py?
args = call.args
if len(args) < 2:
return self.fail_namedtuple_arg(
"Too few arguments for namedtuple()", call)
defaults = [] # type: List[Expression]
if len(args) > 2:
# Typed namedtuple doesn't support additional arguments.
if fullname == 'typing.NamedTuple':
return self.fail_namedtuple_arg(
"Too many arguments for NamedTuple()", call)
for i, arg_name in enumerate(call.arg_names[2:], 2):
if arg_name == 'defaults':
arg = args[i]
# We don't care what the values are, as long as the argument is an iterable
# and we can count how many defaults there are.
if isinstance(arg, (ListExpr, TupleExpr)):
defaults = list(arg.items)
else:
self.fail(
"List or tuple literal expected as the defaults argument to "
"namedtuple()", arg)
break
if call.arg_kinds[:2] != [ARG_POS, ARG_POS]:
return self.fail_namedtuple_arg(
"Unexpected arguments to namedtuple()", call)
if not isinstance(args[0], (StrExpr, BytesExpr, UnicodeExpr)):
return self.fail_namedtuple_arg(
"namedtuple() expects a string literal as the first argument",
call)
types = [] # type: List[Type]
ok = True
if not isinstance(args[1], (ListExpr, TupleExpr)):
if (fullname == 'collections.namedtuple'
and isinstance(args[1],
(StrExpr, BytesExpr, UnicodeExpr))):
str_expr = args[1]
items = str_expr.value.replace(',', ' ').split()
else:
return self.fail_namedtuple_arg(
"List or tuple literal expected as the second argument to namedtuple()",
call)
else:
listexpr = args[1]
if fullname == 'collections.namedtuple':
# The fields argument contains just names, with implicit Any types.
if any(not isinstance(item, (StrExpr, BytesExpr, UnicodeExpr))
for item in listexpr.items):
return self.fail_namedtuple_arg(
"String literal expected as namedtuple() item", call)
items = [
cast(Union[StrExpr, BytesExpr, UnicodeExpr], item).value
for item in listexpr.items
]
else:
# The fields argument contains (name, type) tuples.
result = self.parse_namedtuple_fields_with_types(
listexpr.items, call)
if result:
items, types, _, ok = result
else:
# One of the types is not ready, defer.
return None
if not types:
types = [AnyType(TypeOfAny.unannotated) for _ in items]
underscore = [item for item in items if item.startswith('_')]
if underscore:
self.fail(
"namedtuple() field names cannot start with an underscore: " +
', '.join(underscore), call)
if len(defaults) > len(items):
self.fail("Too many defaults given in call to namedtuple()", call)
defaults = defaults[:len(items)]
return items, types, defaults, ok
def visit_Str(self, n: ast3.Str) -> Type:
return (parse_type_comment(n.s.strip(), self.line, self.errors)
or AnyType(TypeOfAny.from_error))
def check_namedtuple_classdef(
self, defn: ClassDef
) -> Optional[Tuple[List[str], List[Type], Dict[str, Expression]]]:
"""Parse and validate fields in named tuple class definition.
Return a three tuple:
* field names
* field types
* field default values
or None, if any of the types are not ready.
"""
if self.options.python_version < (3, 6):
self.fail(
'NamedTuple class syntax is only supported in Python 3.6',
defn)
return [], [], {}
if len(defn.base_type_exprs) > 1:
self.fail('NamedTuple should be a single base', defn)
items = [] # type: List[str]
types = [] # type: List[Type]
default_items = {} # type: Dict[str, Expression]
for stmt in defn.defs.body:
if not isinstance(stmt, AssignmentStmt):
# Still allow pass or ... (for empty namedtuples).
if (isinstance(stmt, PassStmt)
or (isinstance(stmt, ExpressionStmt)
and isinstance(stmt.expr, EllipsisExpr))):
continue
# Also allow methods, including decorated ones.
if isinstance(stmt, (Decorator, FuncBase)):
continue
# And docstrings.
if (isinstance(stmt, ExpressionStmt)
and isinstance(stmt.expr, StrExpr)):
continue
self.fail(NAMEDTUP_CLASS_ERROR, stmt)
elif len(stmt.lvalues) > 1 or not isinstance(
stmt.lvalues[0], NameExpr):
# An assignment, but an invalid one.
self.fail(NAMEDTUP_CLASS_ERROR, stmt)
else:
# Append name and type in this case...
name = stmt.lvalues[0].name
items.append(name)
if stmt.type is None:
types.append(AnyType(TypeOfAny.unannotated))
else:
analyzed = self.api.anal_type(stmt.type)
if analyzed is None:
# Something is incomplete. We need to defer this named tuple.
return None
types.append(analyzed)
# ...despite possible minor failures that allow further analyzis.
if name.startswith('_'):
self.fail(
'NamedTuple field name cannot start with an underscore: {}'
.format(name), stmt)
if stmt.type is None or hasattr(
stmt, 'new_syntax') and not stmt.new_syntax:
self.fail(NAMEDTUP_CLASS_ERROR, stmt)
elif isinstance(stmt.rvalue, TempNode):
# x: int assigns rvalue to TempNode(AnyType())
if default_items:
self.fail(
'Non-default NamedTuple fields cannot follow default fields',
stmt)
else:
default_items[name] = stmt.rvalue
return items, types, default_items
def do_func_def(self,
n: Union[ast3.FunctionDef, ast3.AsyncFunctionDef],
is_coroutine: bool = False) -> Union[FuncDef, Decorator]:
"""Helper shared between visit_FunctionDef and visit_AsyncFunctionDef."""
no_type_check = bool(
n.decorator_list
and any(is_no_type_check_decorator(d) for d in n.decorator_list))
args = self.transform_args(n.args,
n.lineno,
no_type_check=no_type_check)
arg_kinds = [arg.kind for arg in args]
arg_names = [arg.variable.name()
for arg in args] # type: List[Optional[str]]
arg_names = [
None if argument_elide_name(name) else name for name in arg_names
]
if special_function_elide_names(n.name):
arg_names = [None] * len(arg_names)
arg_types = [] # type: List[Optional[Type]]
if no_type_check:
arg_types = [None] * len(args)
return_type = None
elif n.type_comment is not None:
try:
func_type_ast = ast3.parse(n.type_comment, '<func_type>',
'func_type')
assert isinstance(func_type_ast, ast3.FunctionType)
# for ellipsis arg
if (len(func_type_ast.argtypes) == 1 and isinstance(
func_type_ast.argtypes[0], ast3.Ellipsis)):
if n.returns:
# PEP 484 disallows both type annotations and type comments
self.fail(messages.DUPLICATE_TYPE_SIGNATURES, n.lineno,
n.col_offset)
arg_types = [
a.type_annotation if a.type_annotation is not None else
AnyType(TypeOfAny.unannotated) for a in args
]
else:
# PEP 484 disallows both type annotations and type comments
if n.returns or any(a.type_annotation is not None
for a in args):
self.fail(messages.DUPLICATE_TYPE_SIGNATURES, n.lineno,
n.col_offset)
translated_args = (TypeConverter(
self.errors, line=n.lineno).translate_expr_list(
func_type_ast.argtypes))
arg_types = [
a if a is not None else AnyType(TypeOfAny.unannotated)
for a in translated_args
]
return_type = TypeConverter(self.errors, line=n.lineno).visit(
func_type_ast.returns)
# add implicit self type
if self.in_class() and len(arg_types) < len(args):
arg_types.insert(0, AnyType(TypeOfAny.special_form))
except SyntaxError:
self.fail(TYPE_COMMENT_SYNTAX_ERROR, n.lineno, n.col_offset)
if n.type_comment and n.type_comment[0] != "(":
self.note('Suggestion: wrap argument types in parentheses',
n.lineno, n.col_offset)
arg_types = [AnyType(TypeOfAny.from_error)] * len(args)
return_type = AnyType(TypeOfAny.from_error)
else:
arg_types = [a.type_annotation for a in args]
return_type = TypeConverter(
self.errors,
line=n.returns.lineno if n.returns else n.lineno).visit(
n.returns)
for arg, arg_type in zip(args, arg_types):
self.set_type_optional(arg_type, arg.initializer)
func_type = None
if any(arg_types) or return_type:
if len(arg_types) != 1 and any(
isinstance(t, EllipsisType) for t in arg_types):
self.fail(
"Ellipses cannot accompany other argument types "
"in function type signature.", n.lineno, 0)
elif len(arg_types) > len(arg_kinds):
self.fail('Type signature has too many arguments', n.lineno, 0)
elif len(arg_types) < len(arg_kinds):
self.fail('Type signature has too few arguments', n.lineno, 0)
else:
func_type = CallableType([
a if a is not None else AnyType(TypeOfAny.unannotated)
for a in arg_types
], arg_kinds, arg_names, return_type if return_type is not None
else AnyType(TypeOfAny.unannotated),
_dummy_fallback)
func_def = FuncDef(n.name, args,
self.as_required_block(n.body, n.lineno), func_type)
if is_coroutine:
func_def.is_coroutine = True
if func_type is not None:
func_type.definition = func_def
func_type.line = n.lineno
if n.decorator_list:
var = Var(func_def.name())
var.is_ready = False
var.set_line(n.decorator_list[0].lineno)
func_def.is_decorated = True
func_def.set_line(n.lineno + len(n.decorator_list))
func_def.body.set_line(func_def.get_line())
return Decorator(func_def,
self.translate_expr_list(n.decorator_list), var)
else:
return func_def
def visit_instance(self, t: Instance) -> Type:
return Instance(t.type,
[AnyType(TypeOfAny.special_form)] * len(t.args),
t.line)
def make_tuple(api: 'TypeChecker', fields: List[MypyType]) -> TupleType:
# fallback for tuples is any builtins.tuple instance
fallback = api.named_generic_type('builtins.tuple',
[AnyType(TypeOfAny.special_form)])
return TupleType(fields, fallback=fallback)
def analyze_member_var_access(name: str, itype: Instance, info: TypeInfo,
node: Context, is_lvalue: bool, is_super: bool,
builtin_type: Callable[[str], Instance],
not_ready_callback: Callable[[str, Context],
None],
msg: MessageBuilder, original_type: Type,
chk: 'mypy.checker.TypeChecker') -> Type:
"""Analyse attribute access that does not target a method.
This is logically part of analyze_member_access and the arguments are similar.
original_type is the type of E in the expression E.var
"""
# It was not a method. Try looking up a variable.
v = lookup_member_var_or_accessor(info, name, is_lvalue)
vv = v
if isinstance(vv, Decorator):
# The associated Var node of a decorator contains the type.
v = vv.var
if isinstance(vv, TypeInfo):
# If the associated variable is a TypeInfo synthesize a Var node for
# the purposes of type checking. This enables us to type check things
# like accessing class attributes on an inner class.
v = Var(name, type=type_object_type(vv, builtin_type))
v.info = info
if isinstance(v, Var):
return analyze_var(name,
v,
itype,
info,
node,
is_lvalue,
msg,
original_type,
not_ready_callback,
chk=chk)
elif isinstance(v, FuncDef):
assert False, "Did not expect a function"
elif not v and name not in [
'__getattr__', '__setattr__', '__getattribute__'
]:
if not is_lvalue:
for method_name in ('__getattribute__', '__getattr__'):
method = info.get_method(method_name)
# __getattribute__ is defined on builtins.object and returns Any, so without
# the guard this search will always find object.__getattribute__ and conclude
# that the attribute exists
if method and method.info.fullname() != 'builtins.object':
function = function_type(method,
builtin_type('builtins.function'))
bound_method = bind_self(function, original_type)
typ = map_instance_to_supertype(itype, method.info)
getattr_type = expand_type_by_instance(bound_method, typ)
if isinstance(getattr_type, CallableType):
return getattr_type.ret_type
else:
setattr_meth = info.get_method('__setattr__')
if setattr_meth and setattr_meth.info.fullname(
) != 'builtins.object':
setattr_func = function_type(setattr_meth,
builtin_type('builtins.function'))
bound_type = bind_self(setattr_func, original_type)
typ = map_instance_to_supertype(itype, setattr_meth.info)
setattr_type = expand_type_by_instance(bound_type, typ)
if isinstance(
setattr_type,
CallableType) and len(setattr_type.arg_types) > 0:
return setattr_type.arg_types[-1]
if itype.type.fallback_to_any:
return AnyType(TypeOfAny.special_form)
# Could not find the member.
if is_super:
msg.undefined_in_superclass(name, node)
return AnyType(TypeOfAny.from_error)
else:
if chk and chk.should_suppress_optional_error([itype]):
return AnyType(TypeOfAny.from_error)
return msg.has_no_attr(original_type, itype, name, node)
def fill_typevars_with_any(instance: Instance) -> Instance:
return reparametrize_instance(instance, [AnyType(TypeOfAny.unannotated)])
def analyse_member_access(name: str, typ: Type, node: Context, is_lvalue: bool,
is_super: bool, basic_types: BasicTypes,
msg: MessageBuilder, override_info: TypeInfo = None,
report_type: Type = None) -> Type:
"""Analyse attribute access.
This is a general operation that supports various different variations:
1. lvalue or non-lvalue access (i.e. setter or getter access)
2. supertype access (when using super(); is_super == True and
override_info should refer to the supertype)
"""
report_type = report_type or typ
if isinstance(typ, Instance):
if name == '__init__' and not is_super:
# Accessing __init__ in statically typed code would compromise
# type safety unless used via super().
msg.fail(messages.CANNOT_ACCESS_INIT, node)
return AnyType()
# The base object has an instance type.
info = typ.type
if override_info:
info = override_info
# Look up the member. First look up the method dictionary.
method = info.get_method(name)
if method:
if is_lvalue:
msg.fail(messages.CANNOT_ASSIGN_TO_METHOD, node)
typ = map_instance_to_supertype(typ, method.info)
return expand_type_by_instance(method_type(method), typ)
else:
# Not a method.
return analyse_member_var_access(name, typ, info, node,
is_lvalue, is_super, msg,
report_type=report_type)
elif isinstance(typ, AnyType):
# The base object has dynamic type.
return AnyType()
elif isinstance(typ, TupleType):
# Actually look up from the 'tuple' type.
return analyse_member_access(name, basic_types.tuple, node, is_lvalue,
is_super, basic_types, msg)
elif (isinstance(typ, FunctionLike) and
cast(FunctionLike, typ).is_type_obj()):
# Class attribute.
# TODO super?
sig = cast(FunctionLike, typ)
itype = cast(Instance, sig.items()[0].ret_type)
result = analyse_class_attribute_access(itype, name, node, is_lvalue,
msg)
if result:
return result
# Look up from the 'type' type.
return analyse_member_access(name, basic_types.type_type, node,
is_lvalue, is_super, basic_types, msg,
report_type=report_type)
elif isinstance(typ, FunctionLike):
# Look up from the 'function' type.
return analyse_member_access(name, basic_types.function, node,
is_lvalue, is_super, basic_types, msg,
report_type=report_type)
return msg.has_no_attr(report_type, name, node)
def _scan_declarative_decorator_stmt(
cls: ClassDef,
api: SemanticAnalyzerPluginInterface,
stmt: Decorator,
cls_metadata: util.DeclClassApplied,
) -> None:
"""Extract mapping information from a @declared_attr in a declarative
class.
E.g.::
@reg.mapped
class MyClass:
# ...
@declared_attr
def updated_at(cls) -> Column[DateTime]:
return Column(DateTime)
Will resolve in mypy as::
@reg.mapped
class MyClass:
# ...
updated_at: Mapped[Optional[datetime.datetime]]
"""
for dec in stmt.decorators:
if (isinstance(dec, (NameExpr, MemberExpr, SymbolNode))
and names._type_id_for_named_node(dec) is names.DECLARED_ATTR):
break
else:
return
dec_index = cls.defs.body.index(stmt)
left_hand_explicit_type: Optional[ProperType] = None
if isinstance(stmt.func.type, CallableType):
func_type = stmt.func.type.ret_type
if isinstance(func_type, UnboundType):
type_id = names._type_id_for_unbound_type(func_type, cls, api)
else:
# this does not seem to occur unless the type argument is
# incorrect
return
if (type_id in {
names.MAPPED,
names.RELATIONSHIP,
names.COMPOSITE_PROPERTY,
names.MAPPER_PROPERTY,
names.SYNONYM_PROPERTY,
names.COLUMN_PROPERTY,
} and func_type.args):
left_hand_explicit_type = get_proper_type(func_type.args[0])
elif type_id is names.COLUMN and func_type.args:
typeengine_arg = func_type.args[0]
if isinstance(typeengine_arg, UnboundType):
sym = api.lookup_qualified(typeengine_arg.name, typeengine_arg)
if sym is not None and isinstance(sym.node, TypeInfo):
if names._has_base_type_id(sym.node, names.TYPEENGINE):
left_hand_explicit_type = UnionType([
infer._extract_python_type_from_typeengine(
api, sym.node, []),
NoneType(),
])
else:
util.fail(
api,
"Column type should be a TypeEngine "
"subclass not '{}'".format(sym.node.fullname),
func_type,
)
if left_hand_explicit_type is None:
# no type on the decorated function. our option here is to
# dig into the function body and get the return type, but they
# should just have an annotation.
msg = ("Can't infer type from @declared_attr on function '{}'; "
"please specify a return type from this function that is "
"one of: Mapped[<python type>], relationship[<target class>], "
"Column[<TypeEngine>], MapperProperty[<python type>]")
util.fail(api, msg.format(stmt.var.name), stmt)
left_hand_explicit_type = AnyType(TypeOfAny.special_form)
left_node = NameExpr(stmt.var.name)
left_node.node = stmt.var
# totally feeling around in the dark here as I don't totally understand
# the significance of UnboundType. It seems to be something that is
# not going to do what's expected when it is applied as the type of
# an AssignmentStatement. So do a feeling-around-in-the-dark version
# of converting it to the regular Instance/TypeInfo/UnionType structures
# we see everywhere else.
if isinstance(left_hand_explicit_type, UnboundType):
left_hand_explicit_type = get_proper_type(
util._unbound_to_instance(api, left_hand_explicit_type))
left_node.node.type = api.named_type("__sa_Mapped",
[left_hand_explicit_type])
# this will ignore the rvalue entirely
# rvalue = TempNode(AnyType(TypeOfAny.special_form))
# rewrite the node as:
# <attr> : Mapped[<typ>] =
# _sa_Mapped._empty_constructor(lambda: <function body>)
# the function body is maintained so it gets type checked internally
column_descriptor = nodes.NameExpr("__sa_Mapped")
column_descriptor.fullname = "sqlalchemy.orm.attributes.Mapped"
mm = nodes.MemberExpr(column_descriptor, "_empty_constructor")
arg = nodes.LambdaExpr(stmt.func.arguments, stmt.func.body)
rvalue = CallExpr(
mm,
[arg],
[nodes.ARG_POS],
["arg1"],
)
new_stmt = AssignmentStmt([left_node], rvalue)
new_stmt.type = left_node.node.type
cls_metadata.mapped_attr_names.append(
(left_node.name, left_hand_explicit_type))
cls.defs.body[dec_index] = new_stmt
