def _supports_protocol(
value: astroid.node_classes.NodeNG, protocol_callback: astroid.FunctionDef
) -> bool:
if isinstance(value, astroid.ClassDef):
if not has_known_bases(value):
return True
# classobj can only be iterable if it has an iterable metaclass
meta = value.metaclass()
if meta is not None:
if protocol_callback(meta):
return True
if isinstance(value, astroid.BaseInstance):
if not has_known_bases(value):
return True
if value.has_dynamic_getattr():
return True
if protocol_callback(value):
return True
# TODO: this is not needed in astroid 2.0, where we can
# check the type using a virtual base class instead.
if (
isinstance(value, _bases.Proxy)
and isinstance(value._proxied, astroid.BaseInstance)
and has_known_bases(value._proxied)
):
value = value._proxied
return protocol_callback(value)
return False
def inherit_from_std_ex(node: astroid.node_classes.NodeNG) -> bool:
"""
Return true if the given class node is subclass of
exceptions.Exception.
"""
if node.name in ('Exception', 'BaseException') \
and node.root().name == EXCEPTIONS_MODULE:
return True
if not hasattr(node, 'ancestors'):
return False
return any(inherit_from_std_ex(parent)
for parent in node.ancestors(recurs=True))
def overrides_a_method(class_node: astroid.node_classes.NodeNG,
name: str) -> bool:
"""return True if <name> is a method overridden from an ancestor"""
for ancestor in class_node.ancestors():
if name in ancestor and isinstance(ancestor[name], astroid.FunctionDef):
return True
return False
def is_super(node: astroid.node_classes.NodeNG) -> bool:
"""return True if the node is referencing the "super" builtin function
"""
if getattr(node, 'name', None) == 'super' and \
node.root().name == BUILTINS_NAME:
return True
return False
def unimplemented_abstract_methods(
node: astroid.node_classes.NodeNG, is_abstract_cb: astroid.FunctionDef = None
) -> Dict[str, astroid.node_classes.NodeNG]:
"""
Get the unimplemented abstract methods for the given *node*.
A method can be considered abstract if the callback *is_abstract_cb*
returns a ``True`` value. The check defaults to verifying that
a method is decorated with abstract methods.
The function will work only for new-style classes. For old-style
classes, it will simply return an empty dictionary.
For the rest of them, it will return a dictionary of abstract method
names and their inferred objects.
"""
if is_abstract_cb is None:
is_abstract_cb = partial(decorated_with, qnames=ABC_METHODS)
visited = {} # type: Dict[str, astroid.node_classes.NodeNG]
try:
mro = reversed(node.mro())
except NotImplementedError:
# Old style class, it will not have a mro.
return {}
except astroid.ResolveError:
# Probably inconsistent hierarchy, don'try
# to figure this out here.
return {}
for ancestor in mro:
for obj in ancestor.values():
infered = obj
if isinstance(obj, astroid.AssignName):
infered = safe_infer(obj)
if not infered:
# Might be an abstract function,
# but since we don't have enough information
# in order to take this decision, we're taking
# the *safe* decision instead.
if obj.name in visited:
del visited[obj.name]
continue
if not isinstance(infered, astroid.FunctionDef):
if obj.name in visited:
del visited[obj.name]
if isinstance(infered, astroid.FunctionDef):
# It's critical to use the original name,
# since after inferring, an object can be something
# else than expected, as in the case of the
# following assignment.
#
# class A:
# def keys(self): pass
# __iter__ = keys
abstract = is_abstract_cb(infered)
if abstract:
visited[obj.name] = infered
elif not abstract and obj.name in visited:
del visited[obj.name]
return visited
def is_postponed_evaluation_enabled(node: astroid.node_classes.NodeNG) -> bool:
"""Check if the postponed evaluation of annotations is enabled"""
name = "annotations"
module = node.root()
stmt = module.locals.get(name)
return (
stmt
and isinstance(stmt[0], astroid.ImportFrom)
and stmt[0].modname == "__future__"
)
def _supports_protocol_method(value: astroid.node_classes.NodeNG, attr: str) -> bool:
try:
attributes = value.getattr(attr)
except astroid.NotFoundError:
return False
first = attributes[0]
if isinstance(first, astroid.AssignName):
if isinstance(first.parent.value, astroid.Const):
return False
return True
def is_default_argument(node: astroid.node_classes.NodeNG) -> bool:
"""return true if the given Name node is used in function or lambda
default argument's value
"""
parent = node.scope()
if isinstance(parent, (astroid.FunctionDef, astroid.Lambda)):
for default_node in parent.args.defaults:
for default_name_node in default_node.nodes_of_class(astroid.Name):
if default_name_node is node:
return True
return False
def node_frame_class(node: astroid.node_classes.NodeNG) -> Optional[astroid.node_classes.NodeNG]:
"""return klass node for a method node (or a staticmethod or a
classmethod), return null otherwise
"""
klass = node.frame()
while klass is not None and not isinstance(klass, astroid.ClassDef):
if klass.parent is None:
klass = None
else:
klass = klass.parent.frame()
return klass
def is_defined_in_scope(
var_node: astroid.node_classes.NodeNG,
varname: str,
scope: astroid.node_classes.NodeNG,
) -> bool:
if isinstance(scope, astroid.If):
for node in scope.body:
if (
isinstance(node, astroid.Assign)
and any(
isinstance(target, astroid.AssignName) and target.name == varname
for target in node.targets
)
) or (isinstance(node, astroid.Nonlocal) and varname in node.names):
return True
elif isinstance(scope, (COMP_NODE_TYPES, astroid.For)):
for ass_node in scope.nodes_of_class(astroid.AssignName):
if ass_node.name == varname:
return True
elif isinstance(scope, astroid.With):
for expr, ids in scope.items:
if expr.parent_of(var_node):
break
if ids and isinstance(ids, astroid.AssignName) and ids.name == varname:
return True
elif isinstance(scope, (astroid.Lambda, astroid.FunctionDef)):
if scope.args.is_argument(varname):
# If the name is found inside a default value
# of a function, then let the search continue
# in the parent's tree.
if scope.args.parent_of(var_node):
try:
scope.args.default_value(varname)
scope = scope.parent
is_defined_in_scope(var_node, varname, scope)
except astroid.NoDefault:
pass
return True
if getattr(scope, "name", None) == varname:
return True
elif isinstance(scope, astroid.ExceptHandler):
if isinstance(scope.name, astroid.AssignName):
ass_node = scope.name
if ass_node.name == varname:
return True
return False
def node_type(node: astroid.node_classes.NodeNG) -> Optional[type]:
"""Return the inferred type for `node`
If there is more than one possible type, or if inferred type is Uninferable or None,
return None
"""
# check there is only one possible type for the assign node. Else we
# don't handle it for now
types = set()
try:
for var_type in node.infer():
if var_type == astroid.Uninferable or is_none(var_type):
continue
types.add(var_type)
if len(types) > 1:
return None
except astroid.InferenceError:
return None
return types.pop() if types else None
def safe_infer(node: astroid.node_classes.NodeNG,
context=None) -> Optional[astroid.node_classes.NodeNG]:
"""Return the inferred value for the given node.
Return None if inference failed or if there is some ambiguity (more than
one node has been inferred).
"""
try:
inferit = node.infer(context=context)
value = next(inferit)
except astroid.InferenceError:
return None
try:
next(inferit)
return None # None if there is ambiguity on the inferred node
except astroid.InferenceError:
return None # there is some kind of ambiguity
except StopIteration:
return value
def clobber_in_except(node: astroid.node_classes.NodeNG) -> Tuple[bool, Tuple[str, str]]:
"""Checks if an assignment node in an except handler clobbers an existing
variable.
Returns (True, args for W0623) if assignment clobbers an existing variable,
(False, None) otherwise.
"""
if isinstance(node, astroid.AssignAttr):
return True, (node.attrname, 'object %r' % (node.expr.as_string(),))
if isinstance(node, astroid.AssignName):
name = node.name
if is_builtin(name):
return (True, (name, 'builtins'))
stmts = node.lookup(name)[1]
if (stmts and not isinstance(stmts[0].assign_type(),
(astroid.Assign, astroid.AugAssign,
astroid.ExceptHandler))):
return True, (name, 'outer scope (line %s)' % stmts[0].fromlineno)
return False, None
def clobber_in_except(
node: astroid.node_classes.NodeNG,
) -> Tuple[bool, Optional[Tuple[str, str]]]:
"""Checks if an assignment node in an except handler clobbers an existing
variable.
Returns (True, args for W0623) if assignment clobbers an existing variable,
(False, None) otherwise.
"""
if isinstance(node, astroid.AssignAttr):
return True, (node.attrname, "object %r" % (node.expr.as_string(),))
if isinstance(node, astroid.AssignName):
name = node.name
if is_builtin(name):
return True, (name, "builtins")
stmts = node.lookup(name)[1]
if stmts and not isinstance(
stmts[0].assign_type(),
(astroid.Assign, astroid.AugAssign, astroid.ExceptHandler),
):
return True, (name, "outer scope (line %s)" % stmts[0].fromlineno)
return False, None
def node_frame_class(node: astroid.node_classes.NodeNG) -> Optional[astroid.ClassDef]:
"""Return the class that is wrapping the given node
The function returns a class for a method node (or a staticmethod or a
classmethod), otherwise it returns `None`.
"""
klass = node.frame()
nodes_to_check = (
astroid.node_classes.NodeNG,
astroid.UnboundMethod,
astroid.BaseInstance,
)
while (
klass
and isinstance(klass, nodes_to_check)
and not isinstance(klass, astroid.ClassDef)
):
if klass.parent is None:
klass = None
else:
klass = klass.parent.frame()
return klass
def is_defined_before(var_node: astroid.node_classes.NodeNG) -> bool:
"""return True if the variable node is defined by a parent node (list,
set, dict, or generator comprehension, lambda) or in a previous sibling
node on the same line (statement_defining ; statement_using)
"""
varname = var_node.name
_node = var_node.parent
while _node:
if is_defined_in_scope(var_node, varname, _node):
return True
_node = _node.parent
# possibly multiple statements on the same line using semi colon separator
stmt = var_node.statement()
_node = stmt.previous_sibling()
lineno = stmt.fromlineno
while _node and _node.fromlineno == lineno:
for assign_node in _node.nodes_of_class(astroid.AssignName):
if assign_node.name == varname:
return True
for imp_node in _node.nodes_of_class((astroid.ImportFrom, astroid.Import)):
if varname in [name[1] or name[0] for name in imp_node.names]:
return True
_node = _node.previous_sibling()
return False
def is_defined_before(var_node: astroid.node_classes.NodeNG) -> bool:
"""return True if the variable node is defined by a parent node (list,
set, dict, or generator comprehension, lambda) or in a previous sibling
node on the same line (statement_defining ; statement_using)
"""
varname = var_node.name
_node = var_node.parent
while _node:
if is_defined_in_scope(var_node, varname, _node):
return True
_node = _node.parent
# possibly multiple statements on the same line using semi colon separator
stmt = var_node.statement()
_node = stmt.previous_sibling()
lineno = stmt.fromlineno
while _node and _node.fromlineno == lineno:
for assign_node in _node.nodes_of_class(astroid.AssignName):
if assign_node.name == varname:
return True
for imp_node in _node.nodes_of_class((astroid.ImportFrom, astroid.Import)):
if varname in [name[1] or name[0] for name in imp_node.names]:
return True
_node = _node.previous_sibling()
return False
def is_error(node: astroid.node_classes.NodeNG) -> bool:
"""return true if the function does nothing but raising an exception"""
for child_node in node.get_children():
if isinstance(child_node, astroid.Raise):
return True
return False
def visit_generic(self, node: astroid.node_classes.NodeNG) -> None:
"""Propagate the visit to the children."""
for child in node.get_children():
self.visit(child)
def overrides_a_method(class_node: astroid.node_classes.NodeNG, name: str) -> bool:
"""return True if <name> is a method overridden from an ancestor"""
for ancestor in class_node.ancestors():
if name in ancestor and isinstance(ancestor[name], astroid.FunctionDef):
return True
return False
def is_postponed_evaluation_enabled(node: astroid.node_classes.NodeNG) -> bool:
"""Check if the postponed evaluation of annotations is enabled"""
module = node.root()
return "annotations" in module.future_imports
def is_error(node: astroid.node_classes.NodeNG) -> bool:
"""return true if the function does nothing but raising an exception"""
for child_node in node.get_children():
if isinstance(child_node, astroid.Raise):
return True
return False
def is_super(node: astroid.node_classes.NodeNG) -> bool:
"""return True if the node is referencing the "super" builtin function"""
if getattr(node, "name",
None) == "super" and node.root().name == BUILTINS_NAME:
return True
return False
def is_builtin_object(node: astroid.node_classes.NodeNG) -> bool:
"""Returns True if the given node is an object from the __builtin__ module."""
return node and node.root().name == BUILTINS_NAME
def is_builtin_object(node: astroid.node_classes.NodeNG) -> bool:
"""Returns True if the given node is an object from the __builtin__ module."""
return node and node.root().name == BUILTINS_NAME
def is_postponed_evaluation_enabled(node: astroid.node_classes.NodeNG) -> bool:
"""Check if the postponed evaluation of annotations is enabled"""
name = 'annotations'
module = node.root()
stmt = module.locals.get(name)
return stmt and isinstance(stmt[0], astroid.ImportFrom) and stmt[0].modname == '__future__'
