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fuchsia / third_party / github.com / pylint-dev / pylint / df5533f7d2d7bbe5092ddbbfb213c561fd263a64 / . / pylint / checkers / utils.py
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# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
# For details: https://github.com/pylint-dev/pylint/blob/main/LICENSE
# Copyright (c) https://github.com/pylint-dev/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
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, Statement
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 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, nodes.FunctionDef)
):
# Avoid the case where var_node_scope is a nested function
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.Try,
nodes.ExceptHandler,
),
):
return True
# possibly multiple statements on the same line using semicolon 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(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
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()
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()
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()
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 infer_kwarg_from_call(call_node: nodes.Call, keyword: str) -> nodes.Name | None:
"""Returns the specified argument from a function's kwargs.
:param nodes.Call call_node: Node representing a function call to check.
:param str keyword: Name of the argument to be extracted.
:returns: The node representing the argument, None if the argument is not found.
:rtype: nodes.Name
"""
for arg in call_node.kwargs:
inferred = safe_infer(arg.value)
if isinstance(inferred, nodes.Dict):
for item in inferred.items:
if item[0].value == keyword:
return item[1]
return None
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 = 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.Try | None:
"""Return the ExceptHandler or the Try node in which the node is."""
current = node
ignores = (nodes.ExceptHandler, nodes.Try)
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 | 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.Try):
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.Try)
def node_ignores_exception(
node: nodes.NodeNG, exception: type[Exception] | str = Exception
) -> bool:
"""Check if the node is in a Try 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))
@lru_cache(maxsize=1024)
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() 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 isinstance(value, nodes.FunctionDef)
and function_arguments_are_ambiguous(inferred, value)
):
return None
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 function_arguments_are_ambiguous(
func1: nodes.FunctionDef, func2: nodes.FunctionDef
) -> bool:
if func1.argnames() != func2.argnames():
return True
# Check ambiguity among function default values
pairs_of_defaults = [
(func1.args.defaults, func2.args.defaults),
(func1.args.kw_defaults, func2.args.kw_defaults),
]
for zippable_default in pairs_of_defaults:
if None in zippable_default:
continue
if len(zippable_default[0]) != len(zippable_default[1]):
return True
for default1, default2 in zip(*zippable_default):
if isinstance(default1, nodes.Const) and isinstance(default2, nodes.Const):
if default1.value != default2.value:
return True
elif isinstance(default1, nodes.Name) and isinstance(default2, nodes.Name):
if default1.name != default2.name:
return True
else:
return True
return False
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_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
elif isinstance(node.test, nodes.Attribute) and node.test.as_string() in {
"six.PY2",
"six.PY3",
}:
return True
return False
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 Try 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: 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 subscript_chain_is_equal(left: nodes.Subscript, right: nodes.Subscript) -> bool:
while isinstance(left, nodes.Subscript) and isinstance(right, nodes.Subscript):
try:
if (
get_subscript_const_value(left).value
!= get_subscript_const_value(right).value
):
return False
left = left.value
right = right.value
except InferredTypeError:
return False
return left.as_string() == right.as_string() # type: ignore[no-any-return]
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]
if isinstance(side, nodes.Subscript) and isinstance(target, nodes.Subscript):
return subscript_chain_is_equal(target, side)
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, nodes.Subscript)):
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 _qualified_name_parts(qualified_module_name: str) -> list[str]:
"""Split the names of the given module into subparts.
For example,
_qualified_name_parts('pylint.checkers.ImportsChecker')
returns
['pylint', 'pylint.checkers', 'pylint.checkers.ImportsChecker']
"""
names = qualified_module_name.split(".")
return [".".join(names[0 : i + 1]) for i in range(len(names))]
def is_module_ignored(
qualified_module_name: str, ignored_modules: Iterable[str]
) -> bool:
ignored_modules = set(ignored_modules)
for current_module in _qualified_name_parts(qualified_module_name):
# Try to match the module name directly
if current_module in ignored_modules:
return True
for ignore in ignored_modules:
# Try to see if the ignores pattern match against the module name.
if fnmatch.fnmatch(current_module, ignore):
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 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
@lru_cache(maxsize=1000)
def overridden_method(
klass: nodes.LocalsDictNodeNG, name: str | None
) -> nodes.FunctionDef | None:
"""Get overridden method if any."""
try:
parent = next(klass.local_attr_ancestors(name))
except (StopIteration, KeyError):
return None
try:
meth_node = parent[name]
except KeyError: # pragma: no cover
# We have found an ancestor defining <name> but it's not in the local
# dictionary. This may happen with astroid built from living objects.
return None
if isinstance(meth_node, nodes.FunctionDef):
return meth_node
return None # pragma: no cover
def clear_lru_caches() -> None:
"""Clear caches holding references to AST nodes."""
caches_holding_node_references: list[_lru_cache_wrapper[Any]] = [
class_is_abstract,
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()
def is_enum_member(node: nodes.AssignName) -> bool:
"""Return `True` if `node` is an Enum member (is an item of the
`__members__` container).
"""
frame = node.frame()
if (
not isinstance(frame, nodes.ClassDef)
or not frame.is_subtype_of("enum.Enum")
or frame.root().qname() == "enum"
):
return False
members = frame.locals.get("__members__")
# A dataclass is one known case for when `members` can be `None`
if members is None:
return False
return node.name in [name_obj.name for value, name_obj in members[0].items]