# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html # For details: https://github.com/PyCQA/pylint/blob/main/LICENSE # Copyright (c) https://github.com/PyCQA/pylint/blob/main/CONTRIBUTORS.txt """Some functions that may be useful for various checkers.""" from __future__ import annotations import builtins import fnmatch import itertools import numbers import re import string import warnings from collections import deque from collections.abc import Iterable, Iterator from functools import lru_cache, partial from re import Match from typing import TYPE_CHECKING, Any, Callable, TypeVar import _string import astroid.objects from astroid import TooManyLevelsError, nodes, util from astroid.context import InferenceContext from astroid.exceptions import AstroidError from astroid.nodes._base_nodes import ImportNode from astroid.typing import InferenceResult, SuccessfulInferenceResult if TYPE_CHECKING: from functools import _lru_cache_wrapper from pylint.checkers import BaseChecker _NodeT = TypeVar("_NodeT", bound=nodes.NodeNG) _CheckerT = TypeVar("_CheckerT", bound="BaseChecker") AstCallbackMethod = Callable[[_CheckerT, _NodeT], None] COMP_NODE_TYPES = ( nodes.ListComp, nodes.SetComp, nodes.DictComp, nodes.GeneratorExp, ) EXCEPTIONS_MODULE = "builtins" ABC_MODULES = {"abc", "_py_abc"} ABC_METHODS = { "abc.abstractproperty", "abc.abstractmethod", "abc.abstractclassmethod", "abc.abstractstaticmethod", } TYPING_PROTOCOLS = frozenset( {"typing.Protocol", "typing_extensions.Protocol", ".Protocol"} ) COMMUTATIVE_OPERATORS = frozenset({"*", "+", "^", "&", "|"}) ITER_METHOD = "__iter__" AITER_METHOD = "__aiter__" NEXT_METHOD = "__next__" GETITEM_METHOD = "__getitem__" CLASS_GETITEM_METHOD = "__class_getitem__" SETITEM_METHOD = "__setitem__" DELITEM_METHOD = "__delitem__" CONTAINS_METHOD = "__contains__" KEYS_METHOD = "keys" # Dictionary which maps the number of expected parameters a # special method can have to a set of special methods. # The following keys are used to denote the parameters restrictions: # # * None: variable number of parameters # * number: exactly that number of parameters # * tuple: these are the odd ones. Basically it means that the function # can work with any number of arguments from that tuple, # although it's best to implement it in order to accept # all of them. _SPECIAL_METHODS_PARAMS = { None: ("__new__", "__init__", "__call__", "__init_subclass__"), 0: ( "__del__", "__repr__", "__str__", "__bytes__", "__hash__", "__bool__", "__dir__", "__len__", "__length_hint__", "__iter__", "__reversed__", "__neg__", "__pos__", "__abs__", "__invert__", "__complex__", "__int__", "__float__", "__index__", "__trunc__", "__floor__", "__ceil__", "__enter__", "__aenter__", "__getnewargs_ex__", "__getnewargs__", "__getstate__", "__reduce__", "__copy__", "__unicode__", "__nonzero__", "__await__", "__aiter__", "__anext__", "__fspath__", "__subclasses__", ), 1: ( "__format__", "__lt__", "__le__", "__eq__", "__ne__", "__gt__", "__ge__", "__getattr__", "__getattribute__", "__delattr__", "__delete__", "__instancecheck__", "__subclasscheck__", "__getitem__", "__missing__", "__delitem__", "__contains__", "__add__", "__sub__", "__mul__", "__truediv__", "__floordiv__", "__rfloordiv__", "__mod__", "__divmod__", "__lshift__", "__rshift__", "__and__", "__xor__", "__or__", "__radd__", "__rsub__", "__rmul__", "__rtruediv__", "__rmod__", "__rdivmod__", "__rpow__", "__rlshift__", "__rrshift__", "__rand__", "__rxor__", "__ror__", "__iadd__", "__isub__", "__imul__", "__itruediv__", "__ifloordiv__", "__imod__", "__ilshift__", "__irshift__", "__iand__", "__ixor__", "__ior__", "__ipow__", "__setstate__", "__reduce_ex__", "__deepcopy__", "__cmp__", "__matmul__", "__rmatmul__", "__imatmul__", "__div__", ), 2: ("__setattr__", "__get__", "__set__", "__setitem__", "__set_name__"), 3: ("__exit__", "__aexit__"), (0, 1): ("__round__",), (1, 2): ("__pow__",), } SPECIAL_METHODS_PARAMS = { name: params for params, methods in _SPECIAL_METHODS_PARAMS.items() for name in methods } PYMETHODS = set(SPECIAL_METHODS_PARAMS) SUBSCRIPTABLE_CLASSES_PEP585 = frozenset( ( "builtins.tuple", "builtins.list", "builtins.dict", "builtins.set", "builtins.frozenset", "builtins.type", "collections.deque", "collections.defaultdict", "collections.OrderedDict", "collections.Counter", "collections.ChainMap", "_collections_abc.Awaitable", "_collections_abc.Coroutine", "_collections_abc.AsyncIterable", "_collections_abc.AsyncIterator", "_collections_abc.AsyncGenerator", "_collections_abc.Iterable", "_collections_abc.Iterator", "_collections_abc.Generator", "_collections_abc.Reversible", "_collections_abc.Container", "_collections_abc.Collection", "_collections_abc.Callable", "_collections_abc.Set", "_collections_abc.MutableSet", "_collections_abc.Mapping", "_collections_abc.MutableMapping", "_collections_abc.Sequence", "_collections_abc.MutableSequence", "_collections_abc.ByteString", "_collections_abc.MappingView", "_collections_abc.KeysView", "_collections_abc.ItemsView", "_collections_abc.ValuesView", "contextlib.AbstractContextManager", "contextlib.AbstractAsyncContextManager", "re.Pattern", "re.Match", ) ) SINGLETON_VALUES = {True, False, None} TERMINATING_FUNCS_QNAMES = frozenset( {"_sitebuiltins.Quitter", "sys.exit", "posix._exit", "nt._exit"} ) class NoSuchArgumentError(Exception): pass class InferredTypeError(Exception): pass def is_inside_lambda(node: nodes.NodeNG) -> bool: """Return whether the given node is inside a lambda.""" warnings.warn( "utils.is_inside_lambda will be removed in favour of calling " "utils.get_node_first_ancestor_of_type(x, nodes.Lambda) in pylint 3.0", DeprecationWarning, stacklevel=2, ) return any(isinstance(parent, nodes.Lambda) for parent in node.node_ancestors()) def get_all_elements( node: nodes.NodeNG, ) -> Iterable[nodes.NodeNG]: """Recursively returns all atoms in nested lists and tuples.""" if isinstance(node, (nodes.Tuple, nodes.List)): for child in node.elts: yield from get_all_elements(child) else: yield node def is_super(node: nodes.NodeNG) -> bool: """Return True if the node is referencing the "super" builtin function.""" if getattr(node, "name", None) == "super" and node.root().name == "builtins": return True return False def is_error(node: nodes.FunctionDef) -> bool: """Return true if the given function node only raises an exception.""" return len(node.body) == 1 and isinstance(node.body[0], nodes.Raise) builtins = builtins.__dict__.copy() # type: ignore[assignment] SPECIAL_BUILTINS = ("__builtins__",) # '__path__', '__file__') def is_builtin_object(node: nodes.NodeNG) -> bool: """Returns True if the given node is an object from the __builtin__ module.""" return node and node.root().name == "builtins" # type: ignore[no-any-return] def is_builtin(name: str) -> bool: """Return true if <name> could be considered as a builtin defined by python.""" return name in builtins or name in SPECIAL_BUILTINS # type: ignore[operator] def is_defined_in_scope( var_node: nodes.NodeNG, varname: str, scope: nodes.NodeNG, ) -> bool: return defnode_in_scope(var_node, varname, scope) is not None # pylint: disable = too-many-branches def defnode_in_scope( var_node: nodes.NodeNG, varname: str, scope: nodes.NodeNG, ) -> nodes.NodeNG | None: if isinstance(scope, nodes.If): for node in scope.body: if isinstance(node, nodes.Nonlocal) and varname in node.names: return node if isinstance(node, nodes.Assign): for target in node.targets: if isinstance(target, nodes.AssignName) and target.name == varname: return target elif isinstance(scope, (COMP_NODE_TYPES, nodes.For)): for ass_node in scope.nodes_of_class(nodes.AssignName): if ass_node.name == varname: return ass_node elif isinstance(scope, nodes.With): for expr, ids in scope.items: if expr.parent_of(var_node): break if ids and isinstance(ids, nodes.AssignName) and ids.name == varname: return ids elif isinstance(scope, (nodes.Lambda, nodes.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 defnode = defnode_in_scope(var_node, varname, scope) except astroid.NoDefault: pass else: return defnode return scope if getattr(scope, "name", None) == varname: return scope elif isinstance(scope, nodes.ExceptHandler): if isinstance(scope.name, nodes.AssignName): ass_node = scope.name if ass_node.name == varname: return ass_node return None def is_defined_before(var_node: nodes.Name) -> bool: """Check if the given variable node is defined before. Verify that the variable node is defined by a parent node (e.g. if or with) earlier than `var_node`, or is defined by a (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 for parent in var_node.node_ancestors(): defnode = defnode_in_scope(var_node, varname, parent) if defnode is None: continue defnode_scope = defnode.scope() if isinstance(defnode_scope, COMP_NODE_TYPES + (nodes.Lambda,)): # Avoid the case where var_node_scope is a nested function # FunctionDef is a Lambda until https://github.com/PyCQA/astroid/issues/291 if isinstance(defnode_scope, nodes.FunctionDef): var_node_scope = var_node.scope() if var_node_scope is not defnode_scope and isinstance( var_node_scope, nodes.FunctionDef ): return False return True if defnode.lineno < var_node.lineno: return True # `defnode` and `var_node` on the same line for defnode_anc in defnode.node_ancestors(): if defnode_anc.lineno != var_node.lineno: continue if isinstance( defnode_anc, ( nodes.For, nodes.While, nodes.With, nodes.TryExcept, nodes.TryFinally, nodes.ExceptHandler, ), ): return True # possibly multiple statements on the same line using semicolon separator stmt = var_node.statement(future=True) _node = stmt.previous_sibling() lineno = stmt.fromlineno while _node and _node.fromlineno == lineno: for assign_node in _node.nodes_of_class(nodes.AssignName): if assign_node.name == varname: return True for imp_node in _node.nodes_of_class((nodes.ImportFrom, nodes.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_default_argument(node: nodes.NodeNG, scope: nodes.NodeNG | None = None) -> bool: """Return true if the given Name node is used in function or lambda default argument's value. """ if not scope: scope = node.scope() if isinstance(scope, (nodes.FunctionDef, nodes.Lambda)): all_defaults = itertools.chain( scope.args.defaults, (d for d in scope.args.kw_defaults if d is not None) ) return any( default_name_node is node for default_node in all_defaults for default_name_node in default_node.nodes_of_class(nodes.Name) ) return False def is_func_decorator(node: nodes.NodeNG) -> bool: """Return true if the name is used in function decorator.""" for parent in node.node_ancestors(): if isinstance(parent, nodes.Decorators): return True if parent.is_statement or isinstance( parent, ( nodes.Lambda, nodes.ComprehensionScope, nodes.ListComp, ), ): break return False def is_ancestor_name(frame: nodes.ClassDef, node: nodes.NodeNG) -> bool: """Return whether `frame` is an astroid.Class node with `node` in the subtree of its bases attribute. """ if not isinstance(frame, nodes.ClassDef): return False return any(node in base.nodes_of_class(nodes.Name) for base in frame.bases) def is_being_called(node: nodes.NodeNG) -> bool: """Return True if node is the function being called in a Call node.""" return isinstance(node.parent, nodes.Call) and node.parent.func is node def assign_parent(node: nodes.NodeNG) -> nodes.NodeNG: """Return the higher parent which is not an AssignName, Tuple or List node.""" while node and isinstance(node, (nodes.AssignName, nodes.Tuple, nodes.List)): node = node.parent return node def overrides_a_method(class_node: nodes.ClassDef, name: str) -> bool: """Return True if <name> is a method overridden from an ancestor which is not the base object class. """ for ancestor in class_node.ancestors(): if ancestor.name == "object": continue if name in ancestor and isinstance(ancestor[name], nodes.FunctionDef): return True return False def only_required_for_messages( *messages: str, ) -> Callable[ [AstCallbackMethod[_CheckerT, _NodeT]], AstCallbackMethod[_CheckerT, _NodeT] ]: """Decorator to store messages that are handled by a checker method as an attribute of the function object. This information is used by ``ASTWalker`` to decide whether to call the decorated method or not. If none of the messages is enabled, the method will be skipped. Therefore, the list of messages must be well maintained at all times! This decorator only has an effect on ``visit_*`` and ``leave_*`` methods of a class inheriting from ``BaseChecker``. """ def store_messages( func: AstCallbackMethod[_CheckerT, _NodeT] ) -> AstCallbackMethod[_CheckerT, _NodeT]: func.checks_msgs = messages # type: ignore[attr-defined] return func return store_messages def check_messages( *messages: str, ) -> Callable[ [AstCallbackMethod[_CheckerT, _NodeT]], AstCallbackMethod[_CheckerT, _NodeT] ]: """Kept for backwards compatibility, deprecated. Use only_required_for_messages instead, which conveys the intent of the decorator much clearer. """ warnings.warn( "utils.check_messages will be removed in favour of calling " "utils.only_required_for_messages in pylint 3.0", DeprecationWarning, stacklevel=2, ) return only_required_for_messages(*messages) class IncompleteFormatString(Exception): """A format string ended in the middle of a format specifier.""" class UnsupportedFormatCharacter(Exception): """A format character in a format string is not one of the supported format characters. """ def __init__(self, index: int) -> None: super().__init__(index) self.index = index def parse_format_string( format_string: str, ) -> tuple[set[str], int, dict[str, str], list[str]]: """Parses a format string, returning a tuple (keys, num_args). Where 'keys' is the set of mapping keys in the format string, and 'num_args' is the number of arguments required by the format string. Raises IncompleteFormatString or UnsupportedFormatCharacter if a parse error occurs. """ keys = set() key_types = {} pos_types = [] num_args = 0 def next_char(i: int) -> tuple[int, str]: i += 1 if i == len(format_string): raise IncompleteFormatString return (i, format_string[i]) i = 0 while i < len(format_string): char = format_string[i] if char == "%": i, char = next_char(i) # Parse the mapping key (optional). key = None if char == "(": depth = 1 i, char = next_char(i) key_start = i while depth != 0: if char == "(": depth += 1 elif char == ")": depth -= 1 i, char = next_char(i) key_end = i - 1 key = format_string[key_start:key_end] # Parse the conversion flags (optional). while char in "#0- +": i, char = next_char(i) # Parse the minimum field width (optional). if char == "*": num_args += 1 i, char = next_char(i) else: while char in string.digits: i, char = next_char(i) # Parse the precision (optional). if char == ".": i, char = next_char(i) if char == "*": num_args += 1 i, char = next_char(i) else: while char in string.digits: i, char = next_char(i) # Parse the length modifier (optional). if char in "hlL": i, char = next_char(i) # Parse the conversion type (mandatory). flags = "diouxXeEfFgGcrs%a" if char not in flags: raise UnsupportedFormatCharacter(i) if key: keys.add(key) key_types[key] = char elif char != "%": num_args += 1 pos_types.append(char) i += 1 return keys, num_args, key_types, pos_types def split_format_field_names( format_string: str, ) -> tuple[str, Iterable[tuple[bool, str]]]: try: return _string.formatter_field_name_split(format_string) # type: ignore[no-any-return] except ValueError as e: raise IncompleteFormatString() from e def collect_string_fields(format_string: str) -> Iterable[str | None]: """Given a format string, return an iterator of all the valid format fields. It handles nested fields as well. """ formatter = string.Formatter() # pylint: disable = too-many-try-statements try: parseiterator = formatter.parse(format_string) for result in parseiterator: if all(item is None for item in result[1:]): # not a replacement format continue name = result[1] nested = result[2] yield name if nested: yield from collect_string_fields(nested) except ValueError as exc: # Probably the format string is invalid. if exc.args[0].startswith("cannot switch from manual"): # On Jython, parsing a string with both manual # and automatic positions will fail with a ValueError, # while on CPython it will simply return the fields, # the validation being done in the interpreter (?). # We're just returning two mixed fields in order # to trigger the format-combined-specification check. yield "" yield "1" return raise IncompleteFormatString(format_string) from exc def parse_format_method_string( format_string: str, ) -> tuple[list[tuple[str, list[tuple[bool, str]]]], int, int]: """Parses a PEP 3101 format string, returning a tuple of (keyword_arguments, implicit_pos_args_cnt, explicit_pos_args). keyword_arguments is the set of mapping keys in the format string, implicit_pos_args_cnt is the number of arguments required by the format string and explicit_pos_args is the number of arguments passed with the position. """ keyword_arguments = [] implicit_pos_args_cnt = 0 explicit_pos_args = set() for name in collect_string_fields(format_string): if name and str(name).isdigit(): explicit_pos_args.add(str(name)) elif name: keyname, fielditerator = split_format_field_names(name) if isinstance(keyname, numbers.Number): explicit_pos_args.add(str(keyname)) try: keyword_arguments.append((keyname, list(fielditerator))) except ValueError as e: raise IncompleteFormatString() from e else: implicit_pos_args_cnt += 1 return keyword_arguments, implicit_pos_args_cnt, len(explicit_pos_args) def is_attr_protected(attrname: str) -> bool: """Return True if attribute name is protected (start with _ and some other details), False otherwise. """ return ( attrname[0] == "_" and attrname != "_" and not (attrname.startswith("__") and attrname.endswith("__")) ) def node_frame_class(node: nodes.NodeNG) -> nodes.ClassDef | None: """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(future=True) nodes_to_check = ( nodes.NodeNG, astroid.UnboundMethod, astroid.BaseInstance, ) while ( klass and isinstance(klass, nodes_to_check) and not isinstance(klass, nodes.ClassDef) ): if klass.parent is None: return None klass = klass.parent.frame(future=True) return klass def get_outer_class(class_node: astroid.ClassDef) -> astroid.ClassDef | None: """Return the class that is the outer class of given (nested) class_node.""" parent_klass = class_node.parent.frame(future=True) return parent_klass if isinstance(parent_klass, astroid.ClassDef) else None def is_attr_private(attrname: str) -> Match[str] | None: """Check that attribute name is private (at least two leading underscores, at most one trailing underscore). """ regex = re.compile("^_{2,10}.*[^_]+_?$") return regex.match(attrname) def get_argument_from_call( call_node: nodes.Call, position: int | None = None, keyword: str | None = None ) -> nodes.Name: """Returns the specified argument from a function call. :param nodes.Call call_node: Node representing a function call to check. :param int position: position of the argument. :param str keyword: the keyword of the argument. :returns: The node representing the argument, None if the argument is not found. :rtype: nodes.Name :raises ValueError: if both position and keyword are None. :raises NoSuchArgumentError: if no argument at the provided position or with the provided keyword. """ if position is None and keyword is None: raise ValueError("Must specify at least one of: position or keyword.") if position is not None: try: return call_node.args[position] except IndexError: pass if keyword and call_node.keywords: for arg in call_node.keywords: if arg.arg == keyword: return arg.value raise NoSuchArgumentError def inherit_from_std_ex(node: nodes.NodeNG | astroid.Instance) -> bool: """Return whether the given class node is subclass of exceptions.Exception. """ ancestors = node.ancestors() if hasattr(node, "ancestors") else [] return any( ancestor.name in {"Exception", "BaseException"} and ancestor.root().name == EXCEPTIONS_MODULE for ancestor in itertools.chain([node], ancestors) ) def error_of_type( handler: nodes.ExceptHandler, error_type: str | type[Exception] | tuple[str | type[Exception], ...], ) -> bool: """Check if the given exception handler catches the given error_type. The *handler* parameter is a node, representing an ExceptHandler node. The *error_type* can be an exception, such as AttributeError, the name of an exception, or it can be a tuple of errors. The function will return True if the handler catches any of the given errors. """ def stringify_error(error: str | type[Exception]) -> str: if not isinstance(error, str): return error.__name__ return error if not isinstance(error_type, tuple): error_type = (error_type,) expected_errors = {stringify_error(error) for error in error_type} if not handler.type: return False return handler.catch(expected_errors) # type: ignore[no-any-return] def decorated_with_property(node: nodes.FunctionDef) -> bool: """Detect if the given function node is decorated with a property.""" if not node.decorators: return False for decorator in node.decorators.nodes: try: if _is_property_decorator(decorator): return True except astroid.InferenceError: pass return False def _is_property_kind(node: nodes.NodeNG, *kinds: str) -> bool: if not isinstance(node, (astroid.UnboundMethod, nodes.FunctionDef)): return False if node.decorators: for decorator in node.decorators.nodes: if isinstance(decorator, nodes.Attribute) and decorator.attrname in kinds: return True return False def is_property_setter(node: nodes.NodeNG) -> bool: """Check if the given node is a property setter.""" return _is_property_kind(node, "setter") def is_property_deleter(node: nodes.NodeNG) -> bool: """Check if the given node is a property deleter.""" return _is_property_kind(node, "deleter") def is_property_setter_or_deleter(node: nodes.NodeNG) -> bool: """Check if the given node is either a property setter or a deleter.""" return _is_property_kind(node, "setter", "deleter") def _is_property_decorator(decorator: nodes.Name) -> bool: for inferred in decorator.infer(): if isinstance(inferred, nodes.ClassDef): if inferred.qname() in {"builtins.property", "functools.cached_property"}: return True for ancestor in inferred.ancestors(): if ancestor.name == "property" and ancestor.root().name == "builtins": return True elif isinstance(inferred, nodes.FunctionDef): # If decorator is function, check if it has exactly one return # and the return is itself a function decorated with property returns: list[nodes.Return] = list( inferred._get_return_nodes_skip_functions() ) if len(returns) == 1 and isinstance( returns[0].value, (nodes.Name, nodes.Attribute) ): inferred = safe_infer(returns[0].value) if ( inferred and isinstance(inferred, astroid.objects.Property) and isinstance(inferred.function, nodes.FunctionDef) ): return decorated_with_property(inferred.function) return False def decorated_with( func: ( nodes.ClassDef | nodes.FunctionDef | astroid.BoundMethod | astroid.UnboundMethod ), qnames: Iterable[str], ) -> bool: """Determine if the `func` node has a decorator with the qualified name `qname`.""" decorators = func.decorators.nodes if func.decorators else [] for decorator_node in decorators: if isinstance(decorator_node, nodes.Call): # We only want to infer the function name decorator_node = decorator_node.func try: if any( i.name in qnames or i.qname() in qnames for i in decorator_node.infer() if i is not None and not isinstance(i, util.UninferableBase) ): return True except astroid.InferenceError: continue return False def uninferable_final_decorators( node: nodes.Decorators, ) -> list[nodes.Attribute | nodes.Name | None]: """Return a list of uninferable `typing.final` decorators in `node`. This function is used to determine if the `typing.final` decorator is used with an unsupported Python version; the decorator cannot be inferred when using a Python version lower than 3.8. """ decorators = [] for decorator in getattr(node, "nodes", []): import_nodes: tuple[nodes.Import | nodes.ImportFrom] | None = None # Get the `Import` node. The decorator is of the form: @module.name if isinstance(decorator, nodes.Attribute): inferred = safe_infer(decorator.expr) if isinstance(inferred, nodes.Module) and inferred.qname() == "typing": _, import_nodes = decorator.expr.lookup(decorator.expr.name) # Get the `ImportFrom` node. The decorator is of the form: @name elif isinstance(decorator, nodes.Name): _, import_nodes = decorator.lookup(decorator.name) # The `final` decorator is expected to be found in the # import_nodes. Continue if we don't find any `Import` or `ImportFrom` # nodes for this decorator. if not import_nodes: continue import_node = import_nodes[0] if not isinstance(import_node, (astroid.Import, astroid.ImportFrom)): continue import_names = dict(import_node.names) # Check if the import is of the form: `from typing import final` is_from_import = ("final" in import_names) and import_node.modname == "typing" # Check if the import is of the form: `import typing` is_import = ("typing" in import_names) and getattr( decorator, "attrname", None ) == "final" if is_from_import or is_import: inferred = safe_infer(decorator) if inferred is None or isinstance(inferred, util.UninferableBase): decorators.append(decorator) return decorators @lru_cache(maxsize=1024) def unimplemented_abstract_methods( node: nodes.ClassDef, is_abstract_cb: nodes.FunctionDef = None ) -> dict[str, nodes.FunctionDef]: """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. 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: dict[str, nodes.FunctionDef] = {} try: mro = reversed(node.mro()) except astroid.ResolveError: # Probably inconsistent hierarchy, don't try to figure this out here. return {} for ancestor in mro: for obj in ancestor.values(): inferred = obj if isinstance(obj, nodes.AssignName): inferred = safe_infer(obj) if not inferred: # 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(inferred, nodes.FunctionDef): if obj.name in visited: del visited[obj.name] if isinstance(inferred, nodes.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(inferred) if abstract: visited[obj.name] = inferred elif not abstract and obj.name in visited: del visited[obj.name] return visited def find_try_except_wrapper_node( node: nodes.NodeNG, ) -> nodes.ExceptHandler | nodes.TryExcept | None: """Return the ExceptHandler or the TryExcept node in which the node is.""" current = node ignores = (nodes.ExceptHandler, nodes.TryExcept) while current and not isinstance(current.parent, ignores): current = current.parent if current and isinstance(current.parent, ignores): return current.parent return None def find_except_wrapper_node_in_scope( node: nodes.NodeNG, ) -> nodes.ExceptHandler | nodes.TryExcept | None: """Return the ExceptHandler in which the node is, without going out of scope.""" for current in node.node_ancestors(): if isinstance(current, astroid.scoped_nodes.LocalsDictNodeNG): # If we're inside a function/class definition, we don't want to keep checking # higher ancestors for `except` clauses, because if these exist, it means our # function/class was defined in an `except` clause, rather than the current code # actually running in an `except` clause. return None if isinstance(current, nodes.ExceptHandler): return current return None def is_from_fallback_block(node: nodes.NodeNG) -> bool: """Check if the given node is from a fallback import block.""" context = find_try_except_wrapper_node(node) if not context: return False if isinstance(context, nodes.ExceptHandler): other_body = context.parent.body handlers = context.parent.handlers else: other_body = itertools.chain.from_iterable( handler.body for handler in context.handlers ) handlers = context.handlers has_fallback_imports = any( isinstance(import_node, (nodes.ImportFrom, nodes.Import)) for import_node in other_body ) ignores_import_error = _except_handlers_ignores_exceptions( handlers, (ImportError, ModuleNotFoundError) ) return ignores_import_error or has_fallback_imports def _except_handlers_ignores_exceptions( handlers: nodes.ExceptHandler, exceptions: tuple[type[ImportError], type[ModuleNotFoundError]], ) -> bool: func = partial(error_of_type, error_type=exceptions) return any(func(handler) for handler in handlers) def get_exception_handlers( node: nodes.NodeNG, exception: type[Exception] | str = Exception ) -> list[nodes.ExceptHandler] | None: """Return the collections of handlers handling the exception in arguments. Args: node (nodes.NodeNG): A node that is potentially wrapped in a try except. exception (builtin.Exception or str): exception or name of the exception. Returns: list: the collection of handlers that are handling the exception or None. """ context = find_try_except_wrapper_node(node) if isinstance(context, nodes.TryExcept): return [ handler for handler in context.handlers if error_of_type(handler, exception) ] return [] def get_contextlib_with_statements(node: nodes.NodeNG) -> Iterator[nodes.With]: """Get all contextlib.with statements in the ancestors of the given node.""" for with_node in node.node_ancestors(): if isinstance(with_node, nodes.With): yield with_node def _suppresses_exception( call: nodes.Call, exception: type[Exception] | str = Exception ) -> bool: """Check if the given node suppresses the given exception.""" if not isinstance(exception, str): exception = exception.__name__ for arg in call.args: inferred = safe_infer(arg) if isinstance(inferred, nodes.ClassDef): if inferred.name == exception: return True elif isinstance(inferred, nodes.Tuple): for elt in inferred.elts: inferred_elt = safe_infer(elt) if ( isinstance(inferred_elt, nodes.ClassDef) and inferred_elt.name == exception ): return True return False def get_contextlib_suppressors( node: nodes.NodeNG, exception: type[Exception] | str = Exception ) -> Iterator[nodes.With]: """Return the contextlib suppressors handling the exception. Args: node (nodes.NodeNG): A node that is potentially wrapped in a contextlib.suppress. exception (builtin.Exception): exception or name of the exception. Yields: nodes.With: A with node that is suppressing the exception. """ for with_node in get_contextlib_with_statements(node): for item, _ in with_node.items: if isinstance(item, nodes.Call): inferred = safe_infer(item.func) if ( isinstance(inferred, nodes.ClassDef) and inferred.qname() == "contextlib.suppress" ): if _suppresses_exception(item, exception): yield with_node def is_node_inside_try_except(node: nodes.Raise) -> bool: """Check if the node is directly under a Try/Except statement (but not under an ExceptHandler!). Args: node (nodes.Raise): the node raising the exception. Returns: bool: True if the node is inside a try/except statement, False otherwise. """ context = find_try_except_wrapper_node(node) return isinstance(context, nodes.TryExcept) def node_ignores_exception( node: nodes.NodeNG, exception: type[Exception] | str = Exception ) -> bool: """Check if the node is in a TryExcept which handles the given exception. If the exception is not given, the function is going to look for bare excepts. """ managing_handlers = get_exception_handlers(node, exception) if managing_handlers: return True return any(get_contextlib_suppressors(node, exception)) def class_is_abstract(node: nodes.ClassDef) -> bool: """Return true if the given class node should be considered as an abstract class. """ # Protocol classes are considered "abstract" if is_protocol_class(node): return True # Only check for explicit metaclass=ABCMeta on this specific class meta = node.declared_metaclass() if meta is not None: if meta.name == "ABCMeta" and meta.root().name in ABC_MODULES: return True for ancestor in node.ancestors(): if ancestor.name == "ABC" and ancestor.root().name in ABC_MODULES: # abc.ABC inheritance return True for method in node.methods(): if method.parent.frame(future=True) is node: if method.is_abstract(pass_is_abstract=False): return True return False def _supports_protocol_method(value: nodes.NodeNG, attr: str) -> bool: try: attributes = value.getattr(attr) except astroid.NotFoundError: return False first = attributes[0] # Return False if a constant is assigned if isinstance(first, nodes.AssignName): this_assign_parent = get_node_first_ancestor_of_type( first, (nodes.Assign, nodes.NamedExpr) ) if this_assign_parent is None: # pragma: no cover # Cannot imagine this being None, but return True to avoid false positives return True if isinstance(this_assign_parent.value, nodes.BaseContainer): if all(isinstance(n, nodes.Const) for n in this_assign_parent.value.elts): return False if isinstance(this_assign_parent.value, nodes.Const): return False return True def is_comprehension(node: nodes.NodeNG) -> bool: comprehensions = ( nodes.ListComp, nodes.SetComp, nodes.DictComp, nodes.GeneratorExp, ) return isinstance(node, comprehensions) def _supports_mapping_protocol(value: nodes.NodeNG) -> bool: return _supports_protocol_method( value, GETITEM_METHOD ) and _supports_protocol_method(value, KEYS_METHOD) def _supports_membership_test_protocol(value: nodes.NodeNG) -> bool: return _supports_protocol_method(value, CONTAINS_METHOD) def _supports_iteration_protocol(value: nodes.NodeNG) -> bool: return _supports_protocol_method(value, ITER_METHOD) or _supports_protocol_method( value, GETITEM_METHOD ) def _supports_async_iteration_protocol(value: nodes.NodeNG) -> bool: return _supports_protocol_method(value, AITER_METHOD) def _supports_getitem_protocol(value: nodes.NodeNG) -> bool: return _supports_protocol_method(value, GETITEM_METHOD) def _supports_setitem_protocol(value: nodes.NodeNG) -> bool: return _supports_protocol_method(value, SETITEM_METHOD) def _supports_delitem_protocol(value: nodes.NodeNG) -> bool: return _supports_protocol_method(value, DELITEM_METHOD) def _is_abstract_class_name(name: str) -> bool: lname = name.lower() is_mixin = lname.endswith("mixin") is_abstract = lname.startswith("abstract") is_base = lname.startswith("base") or lname.endswith("base") return is_mixin or is_abstract or is_base def is_inside_abstract_class(node: nodes.NodeNG) -> bool: while node is not None: if isinstance(node, nodes.ClassDef): if class_is_abstract(node): return True name = getattr(node, "name", None) if name is not None and _is_abstract_class_name(name): return True node = node.parent return False def _supports_protocol( value: nodes.NodeNG, protocol_callback: Callable[[nodes.NodeNG], bool] ) -> bool: if isinstance(value, nodes.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 if isinstance(value, nodes.ComprehensionScope): return True if ( isinstance(value, astroid.bases.Proxy) and isinstance(value._proxied, astroid.BaseInstance) and has_known_bases(value._proxied) ): value = value._proxied return protocol_callback(value) return False def is_iterable(value: nodes.NodeNG, check_async: bool = False) -> bool: if check_async: protocol_check = _supports_async_iteration_protocol else: protocol_check = _supports_iteration_protocol return _supports_protocol(value, protocol_check) def is_mapping(value: nodes.NodeNG) -> bool: return _supports_protocol(value, _supports_mapping_protocol) def supports_membership_test(value: nodes.NodeNG) -> bool: supported = _supports_protocol(value, _supports_membership_test_protocol) return supported or is_iterable(value) def supports_getitem(value: nodes.NodeNG, node: nodes.NodeNG) -> bool: if isinstance(value, nodes.ClassDef): if _supports_protocol_method(value, CLASS_GETITEM_METHOD): return True if is_postponed_evaluation_enabled(node) and is_node_in_type_annotation_context( node ): return True return _supports_protocol(value, _supports_getitem_protocol) def supports_setitem(value: nodes.NodeNG, _: nodes.NodeNG) -> bool: return _supports_protocol(value, _supports_setitem_protocol) def supports_delitem(value: nodes.NodeNG, _: nodes.NodeNG) -> bool: return _supports_protocol(value, _supports_delitem_protocol) def _get_python_type_of_node(node: nodes.NodeNG) -> str | None: pytype: Callable[[], str] | None = getattr(node, "pytype", None) if callable(pytype): return pytype() return None @lru_cache(maxsize=1024) def safe_infer( node: nodes.NodeNG, context: InferenceContext | None = None, *, compare_constants: bool = False, ) -> InferenceResult | None: """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 of different types). If compare_constants is True and if multiple constants are inferred, unequal inferred values are also considered ambiguous and return None. """ inferred_types: set[str | None] = set() try: infer_gen = node.infer(context=context) value = next(infer_gen) except astroid.InferenceError: return None except Exception as e: # pragma: no cover raise AstroidError from e if not isinstance(value, util.UninferableBase): inferred_types.add(_get_python_type_of_node(value)) # pylint: disable = too-many-try-statements try: for inferred in infer_gen: inferred_type = _get_python_type_of_node(inferred) if inferred_type not in inferred_types: return None # If there is ambiguity on the inferred node. if ( compare_constants and isinstance(inferred, nodes.Const) and isinstance(value, nodes.Const) and inferred.value != value.value ): return None if ( isinstance(inferred, nodes.FunctionDef) and inferred.args.args is not None and isinstance(value, nodes.FunctionDef) and value.args.args is not None and len(inferred.args.args) != len(value.args.args) ): return None # Different number of arguments indicates ambiguity except astroid.InferenceError: return None # There is some kind of ambiguity except StopIteration: return value except Exception as e: # pragma: no cover raise AstroidError from e return value if len(inferred_types) <= 1 else None @lru_cache(maxsize=512) def infer_all( node: nodes.NodeNG, context: InferenceContext | None = None ) -> list[InferenceResult]: try: return list(node.infer(context=context)) except astroid.InferenceError: return [] except Exception as e: # pragma: no cover raise AstroidError from e def has_known_bases( klass: nodes.ClassDef, context: InferenceContext | None = None ) -> bool: """Return true if all base classes of a class could be inferred.""" try: return klass._all_bases_known # type: ignore[no-any-return] except AttributeError: pass for base in klass.bases: result = safe_infer(base, context=context) if ( not isinstance(result, nodes.ClassDef) or result is klass or not has_known_bases(result, context=context) ): klass._all_bases_known = False return False klass._all_bases_known = True return True def is_none(node: nodes.NodeNG) -> bool: return ( node is None or (isinstance(node, nodes.Const) and node.value is None) or (isinstance(node, nodes.Name) and node.name == "None") ) def node_type(node: nodes.NodeNG) -> SuccessfulInferenceResult | None: """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[SuccessfulInferenceResult] = set() try: for var_type in node.infer(): if isinstance(var_type, util.UninferableBase) 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 is_registered_in_singledispatch_function(node: nodes.FunctionDef) -> bool: """Check if the given function node is a singledispatch function.""" singledispatch_qnames = ( "functools.singledispatch", "singledispatch.singledispatch", ) if not isinstance(node, nodes.FunctionDef): return False decorators = node.decorators.nodes if node.decorators else [] for decorator in decorators: # func.register are function calls or register attributes # when the function is annotated with types if isinstance(decorator, nodes.Call): func = decorator.func elif isinstance(decorator, nodes.Attribute): func = decorator else: continue if not isinstance(func, nodes.Attribute) or func.attrname != "register": continue try: func_def = next(func.expr.infer()) except astroid.InferenceError: continue if isinstance(func_def, nodes.FunctionDef): return decorated_with(func_def, singledispatch_qnames) return False def find_inferred_fn_from_register(node: nodes.NodeNG) -> nodes.FunctionDef | None: # func.register are function calls or register attributes # when the function is annotated with types if isinstance(node, nodes.Call): func = node.func elif isinstance(node, nodes.Attribute): func = node else: return None if not isinstance(func, nodes.Attribute) or func.attrname != "register": return None func_def = safe_infer(func.expr) if not isinstance(func_def, nodes.FunctionDef): return None return func_def def is_registered_in_singledispatchmethod_function(node: nodes.FunctionDef) -> bool: """Check if the given function node is a singledispatchmethod function.""" singledispatchmethod_qnames = ( "functools.singledispatchmethod", "singledispatch.singledispatchmethod", ) decorators = node.decorators.nodes if node.decorators else [] for decorator in decorators: func_def = find_inferred_fn_from_register(decorator) if func_def: return decorated_with(func_def, singledispatchmethod_qnames) return False def get_node_last_lineno(node: nodes.NodeNG) -> int: """Get the last lineno of the given node. For a simple statement this will just be node.lineno, but for a node that has child statements (e.g. a method) this will be the lineno of the last child statement recursively. """ # 'finalbody' is always the last clause in a try statement, if present if getattr(node, "finalbody", False): return get_node_last_lineno(node.finalbody[-1]) # For if, while, and for statements 'orelse' is always the last clause. # For try statements 'orelse' is the last in the absence of a 'finalbody' if getattr(node, "orelse", False): return get_node_last_lineno(node.orelse[-1]) # try statements have the 'handlers' last if there is no 'orelse' or 'finalbody' if getattr(node, "handlers", False): return get_node_last_lineno(node.handlers[-1]) # All compound statements have a 'body' if getattr(node, "body", False): return get_node_last_lineno(node.body[-1]) # Not a compound statement return node.lineno # type: ignore[no-any-return] def is_postponed_evaluation_enabled(node: nodes.NodeNG) -> bool: """Check if the postponed evaluation of annotations is enabled.""" module = node.root() return "annotations" in module.future_imports def is_class_subscriptable_pep585_with_postponed_evaluation_enabled( value: nodes.ClassDef, node: nodes.NodeNG ) -> bool: """Check if class is subscriptable with PEP 585 and postponed evaluation enabled. """ warnings.warn( "'is_class_subscriptable_pep585_with_postponed_evaluation_enabled' has been " "deprecated and will be removed in pylint 3.0. " "Use 'is_postponed_evaluation_enabled(node) and " "is_node_in_type_annotation_context(node)' instead.", DeprecationWarning, stacklevel=2, ) return ( is_postponed_evaluation_enabled(node) and value.qname() in SUBSCRIPTABLE_CLASSES_PEP585 and is_node_in_type_annotation_context(node) ) def is_node_in_type_annotation_context(node: nodes.NodeNG) -> bool: """Check if node is in type annotation context. Check for 'AnnAssign', function 'Arguments', or part of function return type annotation. """ # pylint: disable=too-many-boolean-expressions current_node, parent_node = node, node.parent while True: if ( isinstance(parent_node, nodes.AnnAssign) and parent_node.annotation == current_node or isinstance(parent_node, nodes.Arguments) and current_node in ( *parent_node.annotations, *parent_node.posonlyargs_annotations, *parent_node.kwonlyargs_annotations, parent_node.varargannotation, parent_node.kwargannotation, ) or isinstance(parent_node, nodes.FunctionDef) and parent_node.returns == current_node ): return True current_node, parent_node = parent_node, parent_node.parent if isinstance(parent_node, nodes.Module): return False def is_subclass_of(child: nodes.ClassDef, parent: nodes.ClassDef) -> bool: """Check if first node is a subclass of second node. :param child: Node to check for subclass. :param parent: Node to check for superclass. :returns: True if child is derived from parent. False otherwise. """ if not all(isinstance(node, nodes.ClassDef) for node in (child, parent)): return False for ancestor in child.ancestors(): try: if astroid.helpers.is_subtype(ancestor, parent): return True except astroid.exceptions._NonDeducibleTypeHierarchy: continue return False @lru_cache(maxsize=1024) def is_overload_stub(node: nodes.NodeNG) -> bool: """Check if a node is a function stub decorated with typing.overload. :param node: Node to check. :returns: True if node is an overload function stub. False otherwise. """ decorators = getattr(node, "decorators", None) return bool(decorators and decorated_with(node, ["typing.overload", "overload"])) def is_protocol_class(cls: nodes.NodeNG) -> bool: """Check if the given node represents a protocol class. :param cls: The node to check :returns: True if the node is or inherits from typing.Protocol directly, false otherwise. """ if not isinstance(cls, nodes.ClassDef): return False # Return if klass is protocol if cls.qname() in TYPING_PROTOCOLS: return True for base in cls.bases: try: for inf_base in base.infer(): if inf_base.qname() in TYPING_PROTOCOLS: return True except astroid.InferenceError: continue return False def is_call_of_name(node: nodes.NodeNG, name: str) -> bool: """Checks if node is a function call with the given name.""" return ( isinstance(node, nodes.Call) and isinstance(node.func, nodes.Name) and node.func.name == name ) def is_test_condition( node: nodes.NodeNG, parent: nodes.NodeNG | None = None, ) -> bool: """Returns true if the given node is being tested for truthiness.""" parent = parent or node.parent if isinstance(parent, (nodes.While, nodes.If, nodes.IfExp, nodes.Assert)): return node is parent.test or parent.test.parent_of(node) if isinstance(parent, nodes.Comprehension): return node in parent.ifs return is_call_of_name(parent, "bool") and parent.parent_of(node) def is_classdef_type(node: nodes.ClassDef) -> bool: """Test if ClassDef node is Type.""" if node.name == "type": return True return any(isinstance(b, nodes.Name) and b.name == "type" for b in node.bases) def is_attribute_typed_annotation( node: nodes.ClassDef | astroid.Instance, attr_name: str ) -> bool: """Test if attribute is typed annotation in current node or any base nodes. """ attribute = node.locals.get(attr_name, [None])[0] if ( attribute and isinstance(attribute, nodes.AssignName) and isinstance(attribute.parent, nodes.AnnAssign) ): return True for base in node.bases: inferred = safe_infer(base) if ( inferred and isinstance(inferred, nodes.ClassDef) and is_attribute_typed_annotation(inferred, attr_name) ): return True return False def is_enum(node: nodes.ClassDef) -> bool: return node.name == "Enum" and node.root().name == "enum" # type: ignore[no-any-return] def is_assign_name_annotated_with(node: nodes.AssignName, typing_name: str) -> bool: """Test if AssignName node has `typing_name` annotation. Especially useful to check for `typing._SpecialForm` instances like: `Union`, `Optional`, `Literal`, `ClassVar`, `Final`. """ if not isinstance(node.parent, nodes.AnnAssign): return False annotation = node.parent.annotation if isinstance(annotation, nodes.Subscript): annotation = annotation.value if ( isinstance(annotation, nodes.Name) and annotation.name == typing_name or isinstance(annotation, nodes.Attribute) and annotation.attrname == typing_name ): return True return False def get_iterating_dictionary_name(node: nodes.For | nodes.Comprehension) -> str | None: """Get the name of the dictionary which keys are being iterated over on a ``nodes.For`` or ``nodes.Comprehension`` node. If the iterating object is not either the keys method of a dictionary or a dictionary itself, this returns None. """ # Is it a proper keys call? if ( isinstance(node.iter, nodes.Call) and isinstance(node.iter.func, nodes.Attribute) and node.iter.func.attrname == "keys" ): inferred = safe_infer(node.iter.func) if not isinstance(inferred, astroid.BoundMethod): return None return node.iter.as_string().rpartition(".keys")[0] # type: ignore[no-any-return] # Is it a dictionary? if isinstance(node.iter, (nodes.Name, nodes.Attribute)): inferred = safe_infer(node.iter) if not isinstance(inferred, nodes.Dict): return None return node.iter.as_string() # type: ignore[no-any-return] return None def get_subscript_const_value(node: nodes.Subscript) -> nodes.Const: """Returns the value 'subscript.slice' of a Subscript node. :param node: Subscript Node to extract value from :returns: Const Node containing subscript value :raises InferredTypeError: if the subscript node cannot be inferred as a Const """ inferred = safe_infer(node.slice) if not isinstance(inferred, nodes.Const): raise InferredTypeError("Subscript.slice cannot be inferred as a nodes.Const") return inferred def get_import_name(importnode: ImportNode, modname: str | None) -> str | None: """Get a prepared module name from the given import node. In the case of relative imports, this will return the absolute qualified module name, which might be useful for debugging. Otherwise, the initial module name is returned unchanged. :param importnode: node representing import statement. :param modname: module name from import statement. :returns: absolute qualified module name of the module used in import. """ if isinstance(importnode, nodes.ImportFrom) and importnode.level: root = importnode.root() if isinstance(root, nodes.Module): try: return root.relative_to_absolute_name( # type: ignore[no-any-return] modname, level=importnode.level ) except TooManyLevelsError: return modname return modname def is_sys_guard(node: nodes.If) -> bool: """Return True if IF stmt is a sys.version_info guard. >>> import sys >>> if sys.version_info > (3, 8): >>> from typing import Literal >>> else: >>> from typing_extensions import Literal """ if isinstance(node.test, nodes.Compare): value = node.test.left if isinstance(value, nodes.Subscript): value = value.value if ( isinstance(value, nodes.Attribute) and value.as_string() == "sys.version_info" ): return True return False def is_typing_guard(node: nodes.If) -> bool: """Return True if IF stmt is a typing guard. >>> from typing import TYPE_CHECKING >>> if TYPE_CHECKING: >>> from xyz import a """ warnings.warn( "This method will be removed in pylint 3.0; use in_type_checking_block() instead.", DeprecationWarning, stacklevel=2, ) # pragma: no cover return isinstance( node.test, (nodes.Name, nodes.Attribute) ) and node.test.as_string().endswith("TYPE_CHECKING") def is_node_in_typing_guarded_import_block(node: nodes.NodeNG) -> bool: """Return True if node is part for guarded `typing.TYPE_CHECKING` if block.""" warnings.warn( "This method will be removed in pylint 3.0; use in_type_checking_block() instead.", DeprecationWarning, stacklevel=2, ) # pragma: no cover return isinstance(node.parent, nodes.If) and is_typing_guard(node.parent) def is_node_in_guarded_import_block(node: nodes.NodeNG) -> bool: """Return True if node is part for guarded if block. I.e. `sys.version_info` or `typing.TYPE_CHECKING` """ warnings.warn( "This method will be removed in pylint 3.0; use in_type_checking_block() instead.", DeprecationWarning, stacklevel=2, ) # pragma: no cover return isinstance(node.parent, nodes.If) and ( is_sys_guard(node.parent) or is_typing_guard(node.parent) ) def is_reassigned_after_current(node: nodes.NodeNG, varname: str) -> bool: """Check if the given variable name is reassigned in the same scope after the current node. """ return any( a.name == varname and a.lineno > node.lineno for a in node.scope().nodes_of_class( (nodes.AssignName, nodes.ClassDef, nodes.FunctionDef) ) ) def is_deleted_after_current(node: nodes.NodeNG, varname: str) -> bool: """Check if the given variable name is deleted in the same scope after the current node. """ return any( getattr(target, "name", None) == varname and target.lineno > node.lineno for del_node in node.scope().nodes_of_class(nodes.Delete) for target in del_node.targets ) def is_function_body_ellipsis(node: nodes.FunctionDef) -> bool: """Checks whether a function body only consists of a single Ellipsis.""" return ( len(node.body) == 1 and isinstance(node.body[0], nodes.Expr) and isinstance(node.body[0].value, nodes.Const) and node.body[0].value.value == Ellipsis ) def is_base_container(node: nodes.NodeNG | None) -> bool: return isinstance(node, nodes.BaseContainer) and not node.elts def is_empty_dict_literal(node: nodes.NodeNG | None) -> bool: return isinstance(node, nodes.Dict) and not node.items def is_empty_str_literal(node: nodes.NodeNG | None) -> bool: return ( isinstance(node, nodes.Const) and isinstance(node.value, str) and not node.value ) def returns_bool(node: nodes.NodeNG) -> bool: """Returns true if a node is a nodes.Return that returns a constant boolean.""" return ( isinstance(node, nodes.Return) and isinstance(node.value, nodes.Const) and isinstance(node.value.value, bool) ) def assigned_bool(node: nodes.NodeNG) -> bool: """Returns true if a node is a nodes.Assign that returns a constant boolean.""" return ( isinstance(node, nodes.Assign) and isinstance(node.value, nodes.Const) and isinstance(node.value.value, bool) ) def get_node_first_ancestor_of_type( node: nodes.NodeNG, ancestor_type: type[_NodeT] | tuple[type[_NodeT], ...] ) -> _NodeT | None: """Return the first parent node that is any of the provided types (or None).""" for ancestor in node.node_ancestors(): if isinstance(ancestor, ancestor_type): return ancestor # type: ignore[no-any-return] return None def get_node_first_ancestor_of_type_and_its_child( node: nodes.NodeNG, ancestor_type: type[_NodeT] | tuple[type[_NodeT], ...] ) -> tuple[None, None] | tuple[_NodeT, nodes.NodeNG]: """Modified version of get_node_first_ancestor_of_type to also return the descendant visited directly before reaching the sought ancestor. Useful for extracting whether a statement is guarded by a try, except, or finally when searching for a TryFinally ancestor. """ child = node for ancestor in node.node_ancestors(): if isinstance(ancestor, ancestor_type): return (ancestor, child) child = ancestor return None, None def in_type_checking_block(node: nodes.NodeNG) -> bool: """Check if a node is guarded by a TYPE_CHECKING guard.""" for ancestor in node.node_ancestors(): if not isinstance(ancestor, nodes.If): continue if isinstance(ancestor.test, nodes.Name): if ancestor.test.name != "TYPE_CHECKING": continue lookup_result = ancestor.test.lookup(ancestor.test.name)[1] if not lookup_result: return False maybe_import_from = lookup_result[0] if ( isinstance(maybe_import_from, nodes.ImportFrom) and maybe_import_from.modname == "typing" ): return True inferred = safe_infer(ancestor.test) if isinstance(inferred, nodes.Const) and inferred.value is False: return True elif isinstance(ancestor.test, nodes.Attribute): if ancestor.test.attrname != "TYPE_CHECKING": continue inferred_module = safe_infer(ancestor.test.expr) if ( isinstance(inferred_module, nodes.Module) and inferred_module.name == "typing" ): return True return False def is_typing_member(node: nodes.NodeNG, names_to_check: tuple[str, ...]) -> bool: """Check if `node` is a member of the `typing` module and has one of the names from `names_to_check`. """ if isinstance(node, nodes.Name): try: import_from = node.lookup(node.name)[1][0] except IndexError: return False if isinstance(import_from, nodes.ImportFrom): return ( import_from.modname == "typing" and import_from.real_name(node.name) in names_to_check ) elif isinstance(node, nodes.Attribute): inferred_module = safe_infer(node.expr) return ( isinstance(inferred_module, nodes.Module) and inferred_module.name == "typing" and node.attrname in names_to_check ) return False @lru_cache() def in_for_else_branch(parent: nodes.NodeNG, stmt: nodes.Statement) -> bool: """Returns True if stmt is inside the else branch for a parent For stmt.""" return isinstance(parent, nodes.For) and any( else_stmt.parent_of(stmt) or else_stmt == stmt for else_stmt in parent.orelse ) def find_assigned_names_recursive( target: nodes.AssignName | nodes.BaseContainer, ) -> Iterator[str]: """Yield the names of assignment targets, accounting for nested ones.""" if isinstance(target, nodes.AssignName): if target.name is not None: yield target.name elif isinstance(target, nodes.BaseContainer): for elt in target.elts: yield from find_assigned_names_recursive(elt) def has_starred_node_recursive( node: nodes.For | nodes.Comprehension | nodes.Set, ) -> Iterator[bool]: """Yield ``True`` if a Starred node is found recursively.""" if isinstance(node, nodes.Starred): yield True elif isinstance(node, nodes.Set): for elt in node.elts: yield from has_starred_node_recursive(elt) elif isinstance(node, (nodes.For, nodes.Comprehension)): for elt in node.iter.elts: yield from has_starred_node_recursive(elt) def is_hashable(node: nodes.NodeNG) -> bool: """Return whether any inferred value of `node` is hashable. When finding ambiguity, return True. """ # pylint: disable = too-many-try-statements try: for inferred in node.infer(): if isinstance(inferred, (nodes.ClassDef, util.UninferableBase)): return True if not hasattr(inferred, "igetattr"): return True hash_fn = next(inferred.igetattr("__hash__")) if hash_fn.parent is inferred: return True if getattr(hash_fn, "value", True) is not None: return True return False except astroid.InferenceError: return True def _is_target_name_in_binop_side( target: nodes.AssignName | nodes.AssignAttr, side: nodes.NodeNG | None ) -> bool: """Determine whether the target name-like node is referenced in the side node.""" if isinstance(side, nodes.Name): if isinstance(target, nodes.AssignName): return target.name == side.name # type: ignore[no-any-return] return False if isinstance(side, nodes.Attribute) and isinstance(target, nodes.AssignAttr): return target.as_string() == side.as_string() # type: ignore[no-any-return] return False def is_augmented_assign(node: nodes.Assign) -> tuple[bool, str]: """Determine if the node is assigning itself (with modifications) to itself. For example: x = 1 + x """ if not isinstance(node.value, nodes.BinOp): return False, "" binop = node.value target = node.targets[0] if not isinstance(target, (nodes.AssignName, nodes.AssignAttr)): return False, "" # We don't want to catch x = "1" + x or x = "%s" % x if isinstance(binop.left, nodes.Const) and isinstance( binop.left.value, (str, bytes) ): return False, "" # This could probably be improved but for now we disregard all assignments from calls if isinstance(binop.left, nodes.Call) or isinstance(binop.right, nodes.Call): return False, "" if _is_target_name_in_binop_side(target, binop.left): return True, binop.op if ( # Unless an operator is commutative, we should not raise (i.e. x = 3/x) binop.op in COMMUTATIVE_OPERATORS and _is_target_name_in_binop_side(target, binop.right) ): inferred_left = safe_infer(binop.left) if isinstance(inferred_left, nodes.Const) and isinstance( inferred_left.value, int ): return True, binop.op return False, "" return False, "" def is_module_ignored( module: nodes.Module, ignored_modules: Iterable[str], ) -> bool: ignored_modules = set(ignored_modules) module_name = module.name module_qname = module.qname() for ignore in ignored_modules: # Try to match the module name / fully qualified name directly if module_qname in ignored_modules or module_name in ignored_modules: return True # Try to see if the ignores pattern match against the module name. if fnmatch.fnmatch(module_qname, ignore): return True # Otherwise, we might have a root module name being ignored, # and the qualified owner has more levels of depth. parts = deque(module_name.split(".")) current_module = "" while parts: part = parts.popleft() if not current_module: current_module = part else: current_module += f".{part}" if current_module in ignored_modules: return True return False def is_singleton_const(node: nodes.NodeNG) -> bool: return isinstance(node, nodes.Const) and any( node.value is value for value in SINGLETON_VALUES ) def is_terminating_func(node: nodes.Call) -> bool: """Detect call to exit(), quit(), os._exit(), or sys.exit().""" if ( not isinstance(node.func, nodes.Attribute) and not (isinstance(node.func, nodes.Name)) or isinstance(node.parent, nodes.Lambda) ): return False try: for inferred in node.func.infer(): if ( hasattr(inferred, "qname") and inferred.qname() in TERMINATING_FUNCS_QNAMES ): return True except (StopIteration, astroid.InferenceError): pass return False def is_class_attr(name: str, klass: nodes.ClassDef) -> bool: try: klass.getattr(name) return True except astroid.NotFoundError: return False def is_defined(name: str, node: nodes.NodeNG) -> bool: """Searches for a tree node that defines the given variable name.""" is_defined_so_far = False if isinstance(node, nodes.NamedExpr): is_defined_so_far = node.target.name == name if isinstance(node, (nodes.Import, nodes.ImportFrom)): is_defined_so_far = any(node_name[0] == name for node_name in node.names) if isinstance(node, nodes.With): is_defined_so_far = any( isinstance(item[1], nodes.AssignName) and item[1].name == name for item in node.items ) if isinstance(node, (nodes.ClassDef, nodes.FunctionDef)): is_defined_so_far = node.name == name if isinstance(node, nodes.AnnAssign): is_defined_so_far = ( node.value and isinstance(node.target, nodes.AssignName) and node.target.name == name ) if isinstance(node, nodes.Assign): is_defined_so_far = any( any( ( ( isinstance(elt, nodes.Starred) and isinstance(elt.value, nodes.AssignName) and elt.value.name == name ) or (isinstance(elt, nodes.AssignName) and elt.name == name) ) for elt in get_all_elements(target) ) for target in node.targets ) return is_defined_so_far or any( is_defined(name, child) for child in node.get_children() ) def get_inverse_comparator(op: str) -> str: """Returns the inverse comparator given a comparator. E.g. when given "==", returns "!=" :param str op: the comparator to look up. :returns: The inverse of the comparator in string format :raises KeyError: if input is not recognized as a comparator """ return { "==": "!=", "!=": "==", "<": ">=", ">": "<=", "<=": ">", ">=": "<", "in": "not in", "not in": "in", "is": "is not", "is not": "is", }[op] def not_condition_as_string( test_node: nodes.Compare | nodes.Name | nodes.UnaryOp | nodes.BoolOp | nodes.BinOp, ) -> str: msg = f"not {test_node.as_string()}" if isinstance(test_node, nodes.UnaryOp): msg = test_node.operand.as_string() elif isinstance(test_node, nodes.BoolOp): msg = f"not ({test_node.as_string()})" elif isinstance(test_node, nodes.Compare): lhs = test_node.left ops, rhs = test_node.ops[0] lower_priority_expressions = ( nodes.Lambda, nodes.UnaryOp, nodes.BoolOp, nodes.IfExp, nodes.NamedExpr, ) lhs = ( f"({lhs.as_string()})" if isinstance(lhs, lower_priority_expressions) else lhs.as_string() ) rhs = ( f"({rhs.as_string()})" if isinstance(rhs, lower_priority_expressions) else rhs.as_string() ) msg = f"{lhs} {get_inverse_comparator(ops)} {rhs}" return msg def clear_lru_caches() -> None: """Clear caches holding references to AST nodes.""" # pylint: disable-next=import-outside-toplevel from pylint.checkers.variables import overridden_method caches_holding_node_references: list[_lru_cache_wrapper[Any]] = [ in_for_else_branch, infer_all, is_overload_stub, overridden_method, unimplemented_abstract_methods, safe_infer, ] for lru in caches_holding_node_references: lru.cache_clear()