def visit_While(self, node):
if utils.condition_is_always_false(node.test):
self._define(self.unreachable_code,
'while',
node,
message="unsatisfiable 'while' condition",
confidence=100)
def _handle_conditional_node(self, node, name):
if utils.condition_is_always_false(node.test):
self._define(
self.unreachable_code,
name,
node,
last_node=node.body[-1],
message="unsatisfiable '{name}' condition".format(**locals()),
confidence=100,
)
elif utils.condition_is_always_true(node.test):
else_body = node.orelse
if else_body:
self._define(
self.unreachable_code,
"else",
else_body[0],
last_node=else_body[-1],
message="unreachable 'else' block",
confidence=100,
)
elif name == "if":
# Redundant if-condition without else block.
self._define(
self.unreachable_code,
name,
node,
message="redundant if-condition".format(**locals()),
confidence=100,
)
def visit_If(self, node):
else_body = getattr(node, 'orelse')
if utils.condition_is_always_true(node.test) and else_body:
self._define(
self.unreachable_code, 'else', else_body[0],
last_node=else_body[-1],
message="unreachable 'else' block",
confidence=100)
elif utils.condition_is_always_false(node.test):
self._define(
self.unreachable_code, 'if', node,
last_node=node.body[-1],
message="unsatisfiable 'if' condition",
confidence=100)
def _handle_conditional_node(self, node, name):
if utils.condition_is_always_false(node.test):
self._define(
self.unreachable_code, name, node,
last_node=node.body[-1],
message="unsatisfiable '{name}' condition".format(**locals()),
confidence=100)
else:
else_body = getattr(node, 'orelse')
if utils.condition_is_always_true(node.test) and else_body:
self._define(
self.unreachable_code, 'else', else_body[0],
last_node=else_body[-1],
message="unreachable 'else' block",
confidence=100)
def test_errors():
conditions = [
'foo',
'__name__ == "__main__"',
'chr(-1)',
'getattr(True, "foo")',
'hasattr(str, "foo")',
'isinstance(True, True)',
'globals()',
'locals()',
'().__class__',
]
for condition in conditions:
condition = ast.parse(condition, mode='eval').body
assert not utils.condition_is_always_false(condition)
assert not utils.condition_is_always_true(condition)
def visit_If(self, node):
else_body = getattr(node, 'orelse')
if utils.condition_is_always_true(node.test) and else_body:
self._define(self.unreachable_code,
'else',
else_body[0],
last_node=else_body[-1],
message="unreachable 'else' block",
confidence=100)
elif utils.condition_is_always_false(node.test):
self._define(self.unreachable_code,
'if',
node,
last_node=node.body[-1],
message="unsatisfiable 'if' condition",
confidence=100)
def test_errors():
conditions = [
"foo",
'__name__ == "__main__"',
"chr(-1)",
'getattr(True, "foo")',
'hasattr(str, "foo")',
"isinstance(True, True)",
"globals()",
"locals()",
"().__class__",
]
for condition in conditions:
condition = ast.parse(condition, mode="eval").body
assert not utils.condition_is_always_false(condition)
assert not utils.condition_is_always_true(condition)
def test_complex_conditions():
conditions = [
('foo and False', True, False),
('foo or False', False, False),
('foo and True', False, False),
('foo or True', False, True),
('False and foo', True, False),
('False and 1', True, False),
('not False', False, True),
('not True', True, False),
('not foo', False, False),
('foo and (False or [])', True, False),
('(foo and bar) or {"a": 1}', False, True),
]
for condition, always_false, always_true in conditions:
condition = ast.parse(condition, mode='eval').body
assert not (always_false and always_true)
assert utils.condition_is_always_false(condition) == always_false
assert utils.condition_is_always_true(condition) == always_true
def test_complex_conditions():
conditions = [
("foo and False", True, False),
("foo or False", False, False),
("foo and True", False, False),
("foo or True", False, True),
("False and foo", True, False),
("False and 1", True, False),
("not False", False, True),
("not True", True, False),
("not foo", False, False),
("foo and (False or [])", True, False),
('(foo and bar) or {"a": 1}', False, True),
]
for condition, always_false, always_true in conditions:
condition = ast.parse(condition, mode="eval").body
assert not (always_false and always_true)
assert utils.condition_is_always_false(condition) == always_false
assert utils.condition_is_always_true(condition) == always_true
def _handle_conditional_node(self, node, name):
if utils.condition_is_always_false(node.test):
self._define(
self.unreachable_code,
name,
node,
last_node=node.body
if isinstance(node, ast.IfExp)
else node.body[-1],
message=f"unsatisfiable '{name}' condition",
confidence=100,
)
elif utils.condition_is_always_true(node.test):
else_body = node.orelse
if name == "ternary":
self._define(
self.unreachable_code,
name,
else_body,
message="unreachable 'else' expression",
confidence=100,
)
elif else_body:
self._define(
self.unreachable_code,
"else",
else_body[0],
last_node=else_body[-1],
message="unreachable 'else' block",
confidence=100,
)
elif name == "if":
# Redundant if-condition without else block.
self._define(
self.unreachable_code,
name,
node,
message="redundant if-condition",
confidence=100,
)
def check_condition(code, result):
condition = ast.parse(code, mode='eval').body
if result:
assert utils.condition_is_always_true(condition)
else:
assert utils.condition_is_always_false(condition)
def visit_While(self, node):
if utils.condition_is_always_false(node.test):
self._define(self.unreachable_code, 'while', node,
message="unsatisfiable 'while' condition",
confidence=100)
