def _infer_from_metaclass_constructor(cls, func):
"""Try to infer what the given *func* constructor is building
:param astroid.FunctionDef func:
A metaclass constructor. Metaclass definitions can be
functions, which should accept three arguments, the name of
the class, the bases of the class and the attributes.
The function could return anything, but usually it should
be a proper metaclass.
:param astroid.ClassDef cls:
The class for which the *func* parameter should generate
a metaclass.
:returns:
The class generated by the function or None,
if we couldn't infer it.
:rtype: astroid.ClassDef
"""
context = astroid.context.InferenceContext()
class_bases = astroid.List()
class_bases.postinit(elts=cls.bases)
attrs = astroid.Dict()
local_names = [(name, values[-1]) for name, values in cls.locals.items()]
attrs.postinit(local_names)
builder_args = astroid.Tuple()
builder_args.postinit([cls.name, class_bases, attrs])
context.callcontext = astroid.context.CallContext(builder_args)
try:
inferred = next(func.infer_call_result(func, context), None)
except astroid.InferenceError:
return None
return inferred or None
def infer_random_sample(node, context=None):
if len(node.args) != 2:
raise astroid.UseInferenceDefault
length = node.args[1]
if not isinstance(length, astroid.Const):
raise astroid.UseInferenceDefault
if not isinstance(length.value, int):
raise astroid.UseInferenceDefault
inferred_sequence = helpers.safe_infer(node.args[0], context=context)
if not inferred_sequence:
raise astroid.UseInferenceDefault
if not isinstance(inferred_sequence, ACCEPTED_ITERABLES_FOR_SAMPLE):
raise astroid.UseInferenceDefault
if length.value > len(inferred_sequence.elts):
# In this case, this will raise a ValueError
raise astroid.UseInferenceDefault
try:
elts = random.sample(inferred_sequence.elts, length.value)
except ValueError:
raise astroid.UseInferenceDefault
new_node = astroid.List(
lineno=node.lineno, col_offset=node.col_offset, parent=node.scope()
)
new_elts = [
_clone_node_with_lineno(elt, parent=new_node, lineno=new_node.lineno)
for elt in elts
]
new_node.postinit(new_elts)
return iter((new_node,))
def transform(self, node: ast.Call) -> ast.AugAssign:
new_node = ast.AugAssign(op="+=")
new_value = ast.List(parent=new_node)
new_arg = node.args[0]
new_arg.parent = new_value
new_value.postinit(elts=[new_arg])
new_node.postinit(target=node.func.expr, value=new_value)
new_node.target.parent = new_node
return new_node
def _nose_tools_trivial_transform():
"""Custom transform for the nose.tools module."""
stub = _BUILDER.string_build('''__all__ = []''')
all_entries = ['ok_', 'eq_']
for pep8_name, method in _nose_tools_functions():
all_entries.append(pep8_name)
stub[pep8_name] = method
# Update the __all__ variable, since nose.tools
# does this manually with .append.
all_assign = stub['__all__'].parent
all_object = astroid.List(all_entries)
all_object.parent = all_assign
all_assign.value = all_object
return stub
def list_node(draw, elt=const_node(), **kwargs):
"""Return a List node with elements drawn from elt.
"""
node = astroid.List()
node.postinit(draw(hs.lists(elt, **kwargs)))
return node
