def infer_issubclass(callnode, context=None):
"""Infer issubclass() calls
:param nodes.Call callnode: an `issubclass` call
:param InferenceContext: the context for the inference
:rtype nodes.Const: Boolean Const value of the `issubclass` call
:raises UseInferenceDefault: If the node cannot be inferred
"""
call = arguments.CallSite.from_call(callnode, context=context)
if call.keyword_arguments:
# issubclass doesn't support keyword arguments
raise UseInferenceDefault("TypeError: issubclass() takes no keyword arguments")
if len(call.positional_arguments) != 2:
raise UseInferenceDefault(
"Expected two arguments, got {count}".format(
count=len(call.positional_arguments)
)
)
# The left hand argument is the obj to be checked
obj_node, class_or_tuple_node = call.positional_arguments
try:
obj_type = next(obj_node.infer(context=context))
except InferenceError as exc:
raise UseInferenceDefault from exc
if not isinstance(obj_type, nodes.ClassDef):
raise UseInferenceDefault("TypeError: arg 1 must be class")
# The right hand argument is the class(es) that the given
# object is to be checked against.
try:
class_container = _class_or_tuple_to_container(
class_or_tuple_node, context=context
)
except InferenceError as exc:
raise UseInferenceDefault from exc
try:
issubclass_bool = helpers.object_issubclass(obj_type, class_container, context)
except AstroidTypeError as exc:
raise UseInferenceDefault("TypeError: " + str(exc)) from exc
except MroError as exc:
raise UseInferenceDefault from exc
return nodes.Const(issubclass_bool)
def infer_issubclass(callnode, context=None):
"""Infer issubclass() calls
:param nodes.Call callnode: an `issubclass` call
:param InferenceContext: the context for the inference
:rtype nodes.Const: Boolean Const value of the `issubclass` call
:raises UseInferenceDefault: If the node cannot be inferred
"""
call = arguments.CallSite.from_call(callnode)
if call.keyword_arguments:
# issubclass doesn't support keyword arguments
raise UseInferenceDefault("TypeError: issubclass() takes no keyword arguments")
if len(call.positional_arguments) != 2:
raise UseInferenceDefault(
"Expected two arguments, got {count}".format(
count=len(call.positional_arguments)
)
)
# The left hand argument is the obj to be checked
obj_node, class_or_tuple_node = call.positional_arguments
try:
obj_type = next(obj_node.infer(context=context))
except InferenceError as exc:
raise UseInferenceDefault from exc
if not isinstance(obj_type, nodes.ClassDef):
raise UseInferenceDefault("TypeError: arg 1 must be class")
# The right hand argument is the class(es) that the given
# object is to be checked against.
try:
class_container = _class_or_tuple_to_container(
class_or_tuple_node, context=context
)
except InferenceError as exc:
raise UseInferenceDefault from exc
try:
issubclass_bool = helpers.object_issubclass(obj_type, class_container, context)
except AstroidTypeError as exc:
raise UseInferenceDefault("TypeError: " + str(exc)) from exc
except MroError as exc:
raise UseInferenceDefault from exc
return nodes.Const(issubclass_bool)
