def _check_use_maxsplit_arg(self, node: nodes.Call) -> None:
"""Add message when accessing first or last elements of a str.split() or str.rsplit()."""
# Check if call is split() or rsplit()
if not (isinstance(node.func, nodes.Attribute)
and node.func.attrname in {"split", "rsplit"} and isinstance(
utils.safe_infer(node.func), astroid.BoundMethod)):
return
try:
utils.get_argument_from_call(node, 0, "sep")
except utils.NoSuchArgumentError:
return
try:
# Ignore if maxsplit arg has been set
utils.get_argument_from_call(node, 1, "maxsplit")
return
except utils.NoSuchArgumentError:
pass
if isinstance(node.parent, nodes.Subscript):
try:
subscript_value = utils.get_subscript_const_value(
node.parent).value
except utils.InferredTypeError:
return
# Check for cases where variable (Name) subscripts may be mutated within a loop
if isinstance(node.parent.slice, nodes.Name):
# Check if loop present within the scope of the node
scope = node.scope()
for loop_node in scope.nodes_of_class(
(nodes.For, nodes.While)):
if not loop_node.parent_of(node):
continue
# Check if var is mutated within loop (Assign/AugAssign)
for assignment_node in loop_node.nodes_of_class(
nodes.AugAssign):
if node.parent.slice.name == assignment_node.target.name:
return
for assignment_node in loop_node.nodes_of_class(
nodes.Assign):
if node.parent.slice.name in [
n.name for n in assignment_node.targets
]:
return
if subscript_value in (-1, 0):
fn_name = node.func.attrname
new_fn = "rsplit" if subscript_value == -1 else "split"
new_name = (
node.func.as_string().rsplit(fn_name, maxsplit=1)[0] +
new_fn +
f"({node.args[0].as_string()}, maxsplit=1)[{subscript_value}]"
)
self.add_message("use-maxsplit-arg",
node=node,
args=(new_name, ))
def _check_use_maxsplit_arg(self, node: astroid.Call) -> None:
"""Add message when accessing first or last elements of a str.split() or str.rsplit()."""
# Check if call is split() or rsplit()
if (
isinstance(node.func, astroid.Attribute)
and node.func.attrname in ("split", "rsplit")
and isinstance(utils.safe_infer(node.func), astroid.BoundMethod)
):
try:
utils.get_argument_from_call(node, 0, "sep")
except utils.NoSuchArgumentError:
return
try:
# Ignore if maxsplit arg has been set
utils.get_argument_from_call(node, 1, "maxsplit")
return
except utils.NoSuchArgumentError:
pass
if isinstance(node.parent, astroid.Subscript):
try:
subscript_value = utils.get_subscript_const_value(node.parent).value
except utils.InferredTypeError:
return
if subscript_value in (-1, 0):
fn_name = node.func.attrname
new_fn = "rsplit" if subscript_value == -1 else "split"
new_name = (
node.func.as_string().rsplit(fn_name, maxsplit=1)[0]
+ new_fn
+ f"({node.args[0].as_string()}, maxsplit=1)[{subscript_value}]"
)
self.add_message("use-maxsplit-arg", node=node, args=(new_name,))