def _infer_type_new_call(self, caller, context):
"""Try to infer what type.__new__(mcs, name, bases, attrs) returns.
In order for such call to be valid, the metaclass needs to be
a subtype of ``type``, the name needs to be a string, the bases
needs to be a tuple of classes and the attributes a dictionary
of strings to values.
"""
from astroid import node_classes
# Verify the metaclass
mcs = next(caller.args[0].infer(context=context))
if mcs.__class__.__name__ != 'ClassDef':
# Not a valid first argument.
return
if not mcs.is_subtype_of("%s.type" % BUILTINS):
# Not a valid metaclass.
return
# Verify the name
name = next(caller.args[1].infer(context=context))
if name.__class__.__name__ != 'Const':
# Not a valid name, needs to be a const.
return
if not isinstance(name.value, str):
# Needs to be a string.
return
# Verify the bases
bases = next(caller.args[2].infer(context=context))
if bases.__class__.__name__ != 'Tuple':
# Needs to be a tuple.
return
inferred_bases = [
next(elt.infer(context=context)) for elt in bases.elts
]
if any(base.__class__.__name__ != 'ClassDef'
for base in inferred_bases):
# All the bases needs to be Classes
return
# Verify the attributes.
attrs = next(caller.args[3].infer(context=context))
if attrs.__class__.__name__ != 'Dict':
# Needs to be a dictionary.
return
cls_locals = collections.defaultdict(list)
for key, value in attrs.items:
key = next(key.infer(context=context))
value = next(value.infer(context=context))
if key.__class__.__name__ != 'Const':
# Something invalid as an attribute.
return
if not isinstance(key.value, str):
# Not a proper attribute.
return
cls_locals[key.value].append(value)
# Build the class from now.
cls = mcs.__class__(name=name.value,
lineno=caller.lineno,
col_offset=caller.col_offset,
parent=caller)
empty = node_classes.Pass()
cls.postinit(bases=bases.elts,
body=[empty],
decorators=[],
newstyle=True,
metaclass=mcs,
keywords=[])
cls.locals = cls_locals
return cls
def _infer_type_new_call(self, caller, context):
"""Try to infer what type.__new__(mcs, name, bases, attrs) returns.
In order for such call to be valid, the metaclass needs to be
a subtype of ``type``, the name needs to be a string, the bases
needs to be a tuple of classes
"""
# pylint: disable=import-outside-toplevel; circular import
from astroid import node_classes
# Verify the metaclass
mcs = next(caller.args[0].infer(context=context))
if mcs.__class__.__name__ != "ClassDef":
# Not a valid first argument.
return None
if not mcs.is_subtype_of("%s.type" % BUILTINS):
# Not a valid metaclass.
return None
# Verify the name
name = next(caller.args[1].infer(context=context))
if name.__class__.__name__ != "Const":
# Not a valid name, needs to be a const.
return None
if not isinstance(name.value, str):
# Needs to be a string.
return None
# Verify the bases
bases = next(caller.args[2].infer(context=context))
if bases.__class__.__name__ != "Tuple":
# Needs to be a tuple.
return None
inferred_bases = [next(elt.infer(context=context)) for elt in bases.elts]
if any(base.__class__.__name__ != "ClassDef" for base in inferred_bases):
# All the bases needs to be Classes
return None
# Verify the attributes.
attrs = next(caller.args[3].infer(context=context))
if attrs.__class__.__name__ != "Dict":
# Needs to be a dictionary.
return None
cls_locals = collections.defaultdict(list)
for key, value in attrs.items:
key = next(key.infer(context=context))
value = next(value.infer(context=context))
# Ignore non string keys
if key.__class__.__name__ == "Const" and isinstance(key.value, str):
cls_locals[key.value].append(value)
# Build the class from now.
cls = mcs.__class__(
name=name.value,
lineno=caller.lineno,
col_offset=caller.col_offset,
parent=caller,
)
empty = node_classes.Pass()
cls.postinit(
bases=bases.elts,
body=[empty],
decorators=[],
newstyle=True,
metaclass=mcs,
keywords=[],
)
cls.locals = cls_locals
return cls
