def calculate_class_abstract_status(typ: TypeInfo, is_stub_file: bool, errors: Errors) -> None:
"""Calculate abstract status of a class.
Set is_abstract of the type to True if the type has an unimplemented
abstract attribute. Also compute a list of abstract attributes.
Report error is required ABCMeta metaclass is missing.
"""
concrete = set() # type: Set[str]
abstract = [] # type: List[str]
abstract_in_this_class = [] # type: List[str]
for base in typ.mro:
for name, symnode in base.names.items():
node = symnode.node
if isinstance(node, OverloadedFuncDef):
# Unwrap an overloaded function definition. We can just
# check arbitrarily the first overload item. If the
# different items have a different abstract status, there
# should be an error reported elsewhere.
func = node.items[0] # type: Optional[Node]
else:
func = node
if isinstance(func, Decorator):
fdef = func.func
if fdef.is_abstract and name not in concrete:
typ.is_abstract = True
abstract.append(name)
if base is typ:
abstract_in_this_class.append(name)
elif isinstance(node, Var):
if node.is_abstract_var and name not in concrete:
typ.is_abstract = True
abstract.append(name)
if base is typ:
abstract_in_this_class.append(name)
concrete.add(name)
# In stubs, abstract classes need to be explicitly marked because it is too
# easy to accidentally leave a concrete class abstract by forgetting to
# implement some methods.
typ.abstract_attributes = sorted(abstract)
if is_stub_file:
if typ.declared_metaclass and typ.declared_metaclass.type.fullname() == 'abc.ABCMeta':
return
if typ.is_protocol:
return
if abstract and not abstract_in_this_class:
def report(message: str, severity: str) -> None:
errors.report(typ.line, typ.column, message, severity=severity)
attrs = ", ".join('"{}"'.format(attr) for attr in sorted(abstract))
report("Class {} has abstract attributes {}".format(typ.fullname(), attrs), 'error')
report("If it is meant to be abstract, add 'abc.ABCMeta' as an explicit metaclass",
'note')
def strip_type_info(self, info: TypeInfo) -> List[SymbolNode]:
info.type_vars = []
info.bases = []
info.is_abstract = False
info.abstract_attributes = []
info.mro = []
info.add_type_vars()
info.tuple_type = None
info.typeddict_type = None
info.tuple_type = None
TypeState.reset_subtype_caches_for(info)
info.declared_metaclass = None
info.metaclass_type = None
# We need to delete any entries that were generated by plugins,
# since they will get regenerated.
to_delete = [(k, v) for k, v in info.names.items() if v.plugin_generated]
for k, _ in to_delete:
del info.names[k]
return [v.node for k, v in to_delete if v.node]
def calculate_class_abstract_status(typ: TypeInfo, is_stub_file: bool,
errors: Errors) -> None:
"""Calculate abstract status of a class.
Set is_abstract of the type to True if the type has an unimplemented
abstract attribute. Also compute a list of abstract attributes.
Report error is required ABCMeta metaclass is missing.
"""
concrete = set() # type: Set[str]
abstract = [] # type: List[str]
abstract_in_this_class = [] # type: List[str]
if typ.is_newtype:
# Special case: NewTypes are considered as always non-abstract, so they can be used as:
# Config = NewType('Config', Mapping[str, str])
# default = Config({'cannot': 'modify'}) # OK
typ.abstract_attributes = []
return
for base in typ.mro:
for name, symnode in base.names.items():
node = symnode.node
if isinstance(node, OverloadedFuncDef):
# Unwrap an overloaded function definition. We can just
# check arbitrarily the first overload item. If the
# different items have a different abstract status, there
# should be an error reported elsewhere.
func = node.items[0] # type: Optional[Node]
else:
func = node
if isinstance(func, Decorator):
fdef = func.func
if fdef.is_abstract and name not in concrete:
typ.is_abstract = True
abstract.append(name)
if base is typ:
abstract_in_this_class.append(name)
elif isinstance(node, Var):
if node.is_abstract_var and name not in concrete:
typ.is_abstract = True
abstract.append(name)
if base is typ:
abstract_in_this_class.append(name)
concrete.add(name)
# In stubs, abstract classes need to be explicitly marked because it is too
# easy to accidentally leave a concrete class abstract by forgetting to
# implement some methods.
typ.abstract_attributes = sorted(abstract)
if is_stub_file:
if typ.declared_metaclass and typ.declared_metaclass.type.fullname(
) == 'abc.ABCMeta':
return
if typ.is_protocol:
return
if abstract and not abstract_in_this_class:
def report(message: str, severity: str) -> None:
errors.report(typ.line, typ.column, message, severity=severity)
attrs = ", ".join('"{}"'.format(attr) for attr in sorted(abstract))
report(
"Class {} has abstract attributes {}".format(
typ.fullname(), attrs), 'error')
report(
"If it is meant to be abstract, add 'abc.ABCMeta' as an explicit metaclass",
'note')
