def visit_any_assign(self, node: AnyAssign) -> None:
"""Used to check assignment variable to itself."""
names = list(name_nodes.flat_variable_names([node]))
self._check_reassignment(node, names)
self._check_unique_assignment(node, names)
self.generic_visit(node)
def visit_locals(self, node: Union[AnyAssignWithWalrus, ast.arg]) -> None:
"""Visits local variable definitions and function arguments."""
if isinstance(node, ast.arg):
names = {node.arg}
else:
names = set(flat_variable_names([node]))
self._scope(node, names, is_local=True)
self._outer_scope(node, names)
self.generic_visit(node)
def _check_consistent_variable_return(self, node: ast.Return) -> None:
if not node.value or not self._is_named_return(node):
return
previous_node = self._get_previous_stmt(node)
if not isinstance(previous_node, AssignNodes):
return
return_names = name_nodes.get_variables_from_node(node.value)
previous_names = list(name_nodes.flat_variable_names([previous_node]))
self._check_for_violations(node, return_names, previous_names)
def _check_attributes_shadowing(self, node: ast.ClassDef) -> None:
class_attributes, instance_attributes = self._get_attributes(node)
class_attribute_names = set(
name_nodes.flat_variable_names(class_attributes), )
for instance_attr in instance_attributes:
if instance_attr.attr in class_attribute_names:
self.add_violation(
oop.ShadowedClassAttributeViolation(
instance_attr,
text=instance_attr.attr,
), )
def visit_any_assign(self, node: AnyAssign) -> None:
"""
Used to check assignment variable to itself.
Raises:
ReassigningVariableToItselfViolation
"""
names = list(name_nodes.flat_variable_names([node]))
# TODO: support NamedExpr
self._check_reassignment(node, names)
self._check_unique_assignment(node, names)
self.generic_visit(node)
def visit_locals(self, node: Union[AnyAssign, ast.arg]) -> None:
"""
Visits local variable definitions and function arguments.
Raises:
BlockAndLocalOverlapViolation
"""
if isinstance(node, ast.arg):
names = {node.arg}
else:
names = set(flat_variable_names([node]))
self._scope(node, names, is_local=True)
self.generic_visit(node)
def visit_any_assign(self, node: AnyAssignWithWalrus) -> None:
"""
Checks that we cannot assign explicit unused variables.
We do not check assigns inside modules and classes,
since there ``_`` prefixed variable means
that it is protected, not unused.
"""
is_inside_class_or_module = isinstance(
nodes.get_context(node),
(ast.ClassDef, ast.Module),
)
self._check_assign_unused(
node,
name_nodes.flat_variable_names([node]),
is_local=not is_inside_class_or_module,
)
self.generic_visit(node)
def _almost_swapped(self, assigns: Sequence[ast.Assign]) -> None:
previous_var: Set[Optional[str]] = set()
for assign in assigns:
current_var = {
first(name_nodes.flat_variable_names([assign])),
first(name_nodes.get_variables_from_node(assign.value)),
}
if not all(map(bool, current_var)):
previous_var.clear()
continue
if current_var == previous_var:
self.add_violation(AlmostSwappedViolation(assign))
if len(previous_var & current_var) == 1:
current_var ^= previous_var
previous_var = current_var
def find_attributed_getters_and_setters(
node: ast.ClassDef, ) -> Iterable[AnyFunctionDef]:
"""Returns nodes of attributed getter or setter methods."""
class_attributes, instance_attributes = classes.get_attributes(
node,
include_annotated=True,
)
flat_class_attributes = name_nodes.flat_variable_names(class_attributes)
attributes_stripped = {
class_attribute.lstrip(UNUSED_PLACEHOLDER)
for class_attribute in flat_class_attributes
}.union({
instance.attr.lstrip(UNUSED_PLACEHOLDER)
for instance in instance_attributes
})
for method in _find_getters_and_setters(node):
if method.name[GETTER_LENGTH:] in attributes_stripped:
yield method
def _check_getters_setters_methods(self, node: ast.ClassDef) -> None:
class_attributes, instance_attributes = classes.get_attributes(
node,
include_annotated=True,
)
flat_class_attributes = name_nodes.flat_variable_names(class_attributes)
attributes_stripped = {
class_attribute.lstrip(constants.UNUSED_PLACEHOLDER)
for class_attribute in flat_class_attributes
}.union({
instance.attr.lstrip(constants.UNUSED_PLACEHOLDER)
for instance in instance_attributes
})
for method in classes.find_getters_and_setters(node):
if method.name[classes.GETTER_LENGTH:] in attributes_stripped:
self.add_violation(
oop.UnpythonicGetterSetterViolation(
method,
text=method.name,
),
)