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scoped_nodes.py
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# Licensed under the LGPL: https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html # For details: https://github.com/pylint-dev/astroid/blob/main/LICENSE # Copyright (c) https://github.com/pylint-dev/astroid/blob/main/CONTRIBUTORS.txt """ This module contains the classes for "scoped" node, i.e. which are opening a new local scope in the language definition : Module, ClassDef, FunctionDef (and Lambda, GeneratorExp, DictComp and SetComp to some extent). """ from __future__ import annotations import io import itertools import os import warnings from collections.abc import Generator, Iterable, Iterator, Sequence from functools import cached_property, lru_cache from typing import TYPE_CHECKING, Any, ClassVar, Literal, NoReturn, TypeVar from astroid import bases, protocols, util from astroid.context import ( CallContext, InferenceContext, bind_context_to_node, copy_context, ) from astroid.exceptions import ( AstroidBuildingError, AstroidTypeError, AttributeInferenceError, DuplicateBasesError, InconsistentMroError, InferenceError, MroError, ParentMissingError, StatementMissing, TooManyLevelsError, ) from astroid.interpreter.dunder_lookup import lookup from astroid.interpreter.objectmodel import ClassModel, FunctionModel, ModuleModel from astroid.manager import AstroidManager from astroid.nodes import ( Arguments, Const, NodeNG, Unknown, _base_nodes, const_factory, node_classes, ) from astroid.nodes.scoped_nodes.mixin import ComprehensionScope, LocalsDictNodeNG from astroid.nodes.scoped_nodes.utils import builtin_lookup from astroid.nodes.utils import Position from astroid.typing import ( InferBinaryOp, InferenceErrorInfo, InferenceResult, SuccessfulInferenceResult, ) if TYPE_CHECKING: from astroid import nodes, objects from astroid.nodes._base_nodes import LookupMixIn ITER_METHODS = ("__iter__", "__getitem__") EXCEPTION_BASE_CLASSES = frozenset({"Exception", "BaseException"}) BUILTIN_DESCRIPTORS = frozenset( {"classmethod", "staticmethod", "builtins.classmethod", "builtins.staticmethod"} ) _T = TypeVar("_T") def _c3_merge(sequences, cls, context): """Merges MROs in *sequences* to a single MRO using the C3 algorithm. Adapted from http://www.python.org/download/releases/2.3/mro/. """ result = [] while True: sequences = [s for s in sequences if s] # purge empty sequences if not sequences: return result for s1 in sequences: # find merge candidates among seq heads candidate = s1[0] for s2 in sequences: if candidate in s2[1:]: candidate = None break # reject the current head, it appears later else: break if not candidate: # Show all the remaining bases, which were considered as # candidates for the next mro sequence. raise InconsistentMroError( message="Cannot create a consistent method resolution order " "for MROs {mros} of class {cls!r}.", mros=sequences, cls=cls, context=context, ) result.append(candidate) # remove the chosen candidate for seq in sequences: if seq[0] == candidate: del seq[0] return None def clean_typing_generic_mro(sequences: list[list[ClassDef]]) -> None: """A class can inherit from typing.Generic directly, as base, and as base of bases. The merged MRO must however only contain the last entry. To prepare for _c3_merge, remove some typing.Generic entries from sequences if multiple are present. This method will check if Generic is in inferred_bases and also part of bases_mro. If true, remove it from inferred_bases as well as its entry the bases_mro. Format sequences: [[self]] + bases_mro + [inferred_bases] """ bases_mro = sequences[1:-1] inferred_bases = sequences[-1] # Check if Generic is part of inferred_bases for i, base in enumerate(inferred_bases): if base.qname() == "typing.Generic": position_in_inferred_bases = i break else: return # Check if also part of bases_mro # Ignore entry for typing.Generic for i, seq in enumerate(bases_mro): if i == position_in_inferred_bases: continue if any(base.qname() == "typing.Generic" for base in seq): break else: return # Found multiple Generics in mro, remove entry from inferred_bases # and the corresponding one from bases_mro inferred_bases.pop(position_in_inferred_bases) bases_mro.pop(position_in_inferred_bases) def clean_duplicates_mro( sequences: list[list[ClassDef]], cls: ClassDef, context: InferenceContext | None, ) -> list[list[ClassDef]]: for sequence in sequences: seen = set() for node in sequence: lineno_and_qname = (node.lineno, node.qname()) if lineno_and_qname in seen: raise DuplicateBasesError( message="Duplicates found in MROs {mros} for {cls!r}.", mros=sequences, cls=cls, context=context, ) seen.add(lineno_and_qname) return sequences def function_to_method(n, klass): if isinstance(n, FunctionDef): if n.type == "classmethod": return bases.BoundMethod(n, klass) if n.type == "property": return n if n.type != "staticmethod": return bases.UnboundMethod(n) return n class Module(LocalsDictNodeNG): """Class representing an :class:`ast.Module` node. >>> import astroid >>> node = astroid.extract_node('import astroid') >>> node <Import l.1 at 0x7f23b2e4e5c0> >>> node.parent <Module l.0 at 0x7f23b2e4eda0> """ _astroid_fields = ("doc_node", "body") doc_node: Const | None """The doc node associated with this node.""" # attributes below are set by the builder module or by raw factories file_bytes: str | bytes | None = None """The string/bytes that this ast was built from.""" file_encoding: str | None = None """The encoding of the source file. This is used to get unicode out of a source file. Python 2 only. """ special_attributes = ModuleModel() """The names of special attributes that this module has.""" # names of module attributes available through the global scope scope_attrs: ClassVar[set[str]] = { "__name__", "__doc__", "__file__", "__path__", "__package__", } """The names of module attributes available through the global scope.""" _other_fields = ( "name", "file", "path", "package", "pure_python", "future_imports", ) _other_other_fields = ("locals", "globals") def __init__( self, name: str, file: str | None = None, path: Sequence[str] | None = None, package: bool = False, pure_python: bool = True, ) -> None: self.name = name """The name of the module.""" self.file = file """The path to the file that this ast has been extracted from. This will be ``None`` when the representation has been built from a built-in module. """ self.path = path self.package = package """Whether the node represents a package or a module.""" self.pure_python = pure_python """Whether the ast was built from source.""" self.globals: dict[str, list[InferenceResult]] """A map of the name of a global variable to the node defining the global.""" self.locals = self.globals = {} """A map of the name of a local variable to the node defining the local.""" self.body: list[node_classes.NodeNG] = [] """The contents of the module.""" self.future_imports: set[str] = set() """The imports from ``__future__``.""" super().__init__( lineno=0, parent=None, col_offset=0, end_lineno=None, end_col_offset=None ) # pylint: enable=redefined-builtin def postinit( self, body: list[node_classes.NodeNG], *, doc_node: Const | None = None ): self.body = body self.doc_node = doc_node def _get_stream(self): if self.file_bytes is not None: return io.BytesIO(self.file_bytes) if self.file is not None: # pylint: disable=consider-using-with stream = open(self.file, "rb") return stream return None def stream(self): """Get a stream to the underlying file or bytes. :type: file or io.BytesIO or None """ return self._get_stream() def block_range(self, lineno: int) -> tuple[int, int]: """Get a range from where this node starts to where this node ends. :param lineno: Unused. :returns: The range of line numbers that this node belongs to. """ return self.fromlineno, self.tolineno def scope_lookup( self, node: LookupMixIn, name: str, offset: int = 0 ) -> tuple[LocalsDictNodeNG, list[node_classes.NodeNG]]: """Lookup where the given variable is assigned. :param node: The node to look for assignments up to. Any assignments after the given node are ignored. :param name: The name of the variable to find assignments for. :param offset: The line offset to filter statements up to. :returns: This scope node and the list of assignments associated to the given name according to the scope where it has been found (locals, globals or builtin). """ if name in self.scope_attrs and name not in self.locals: try: return self, self.getattr(name) except AttributeInferenceError: return self, [] return self._scope_lookup(node, name, offset) def pytype(self) -> Literal["builtins.module"]: """Get the name of the type that this node represents. :returns: The name of the type. """ return "builtins.module" def display_type(self) -> str: """A human readable type of this node. :returns: The type of this node. :rtype: str """ return "Module" def getattr( self, name, context: InferenceContext | None = None, ignore_locals=False ): if not name: raise AttributeInferenceError(target=self, attribute=name, context=context) result = [] name_in_locals = name in self.locals if name in self.special_attributes and not ignore_locals and not name_in_locals: result = [self.special_attributes.lookup(name)] if name == "__name__": result.append(const_factory("__main__")) elif not ignore_locals and name_in_locals: result = self.locals[name] elif self.package: try: result = [self.import_module(name, relative_only=True)] except (AstroidBuildingError, SyntaxError) as exc: raise AttributeInferenceError( target=self, attribute=name, context=context ) from exc result = [n for n in result if not isinstance(n, node_classes.DelName)] if result: return result raise AttributeInferenceError(target=self, attribute=name, context=context) def igetattr( self, name: str, context: InferenceContext | None = None ) -> Iterator[InferenceResult]: """Infer the possible values of the given variable. :param name: The name of the variable to infer. :returns: The inferred possible values. """ # set lookup name since this is necessary to infer on import nodes for # instance context = copy_context(context) context.lookupname = name try: return bases._infer_stmts(self.getattr(name, context), context, frame=self) except AttributeInferenceError as error: raise InferenceError( str(error), target=self, attribute=name, context=context ) from error def fully_defined(self) -> bool: """Check if this module has been build from a .py file. If so, the module contains a complete representation, including the code. :returns: Whether the module has been built from a .py file. """ return self.file is not None and self.file.endswith(".py") def statement(self, *, future: Literal[None, True] = None) -> NoReturn: """The first parent node, including self, marked as statement node. When called on a :class:`Module` this raises a StatementMissing. """ if future is not None: warnings.warn( "The future arg will be removed in astroid 4.0.", DeprecationWarning, stacklevel=2, ) raise StatementMissing(target=self) def previous_sibling(self): """The previous sibling statement. :returns: The previous sibling statement node. :rtype: NodeNG or None """ def next_sibling(self): """The next sibling statement node. :returns: The next sibling statement node. :rtype: NodeNG or None """ _absolute_import_activated = True def absolute_import_activated(self) -> bool: """Whether :pep:`328` absolute import behaviour has been enabled. :returns: Whether :pep:`328` has been enabled. """ return self._absolute_import_activated def import_module( self, modname: str, relative_only: bool = False, level: int | None = None, use_cache: bool = True, ) -> Module: """Get the ast for a given module as if imported from this module. :param modname: The name of the module to "import". :param relative_only: Whether to only consider relative imports. :param level: The level of relative import. :param use_cache: Whether to use the astroid_cache of modules. :returns: The imported module ast. """ if relative_only and level is None: level = 0 absmodname = self.relative_to_absolute_name(modname, level) try: return AstroidManager().ast_from_module_name( absmodname, use_cache=use_cache ) except AstroidBuildingError: # we only want to import a sub module or package of this module, # skip here if relative_only: raise # Don't repeat the same operation, e.g. for missing modules # like "_winapi" or "nt" on POSIX systems. if modname == absmodname: raise return AstroidManager().ast_from_module_name(modname, use_cache=use_cache) def relative_to_absolute_name(self, modname: str, level: int | None) -> str: """Get the absolute module name for a relative import. The relative import can be implicit or explicit. :param modname: The module name to convert. :param level: The level of relative import. :returns: The absolute module name. :raises TooManyLevelsError: When the relative import refers to a module too far above this one. """ # XXX this returns non sens when called on an absolute import # like 'pylint.checkers.astroid.utils' # XXX doesn't return absolute name if self.name isn't absolute name if self.absolute_import_activated() and level is None: return modname if level: if self.package: level = level - 1 package_name = self.name.rsplit(".", level)[0] elif ( self.path and not os.path.exists(os.path.dirname(self.path[0]) + "/__init__.py") and os.path.exists( os.path.dirname(self.path[0]) + "/" + modname.split(".")[0] ) ): level = level - 1 package_name = "" else: package_name = self.name.rsplit(".", level)[0] if level and self.name.count(".") < level: raise TooManyLevelsError(level=level, name=self.name) elif self.package: package_name = self.name else: package_name = self.name.rsplit(".", 1)[0] if package_name: if not modname: return package_name return f"{package_name}.{modname}" return modname def wildcard_import_names(self): """The list of imported names when this module is 'wildcard imported'. It doesn't include the '__builtins__' name which is added by the current CPython implementation of wildcard imports. :returns: The list of imported names. :rtype: list(str) """ # We separate the different steps of lookup in try/excepts # to avoid catching too many Exceptions default = [name for name in self.keys() if not name.startswith("_")] try: all_values = self["__all__"] except KeyError: return default try: explicit = next(all_values.assigned_stmts()) except (InferenceError, StopIteration): return default except AttributeError: # not an assignment node # XXX infer? return default # Try our best to detect the exported name. inferred = [] try: explicit = next(explicit.infer()) except (InferenceError, StopIteration): return default if not isinstance(explicit, (node_classes.Tuple, node_classes.List)): return default def str_const(node) -> bool: return isinstance(node, node_classes.Const) and isinstance(node.value, str) for node in explicit.elts: if str_const(node): inferred.append(node.value) else: try: inferred_node = next(node.infer()) except (InferenceError, StopIteration): continue if str_const(inferred_node): inferred.append(inferred_node.value) return inferred def public_names(self): """The list of the names that are publicly available in this module. :returns: The list of public names. :rtype: list(str) """ return [name for name in self.keys() if not name.startswith("_")] def bool_value(self, context: InferenceContext | None = None) -> bool: """Determine the boolean value of this node. :returns: The boolean value of this node. For a :class:`Module` this is always ``True``. """ return True def get_children(self): yield from self.body def frame(self: _T, *, future: Literal[None, True] = None) -> _T: """The node's frame node. A frame node is a :class:`Module`, :class:`FunctionDef`, :class:`ClassDef` or :class:`Lambda`. :returns: The node itself. """ return self def _infer( self, context: InferenceContext | None = None, **kwargs: Any ) -> Generator[Module]: yield self class GeneratorExp(ComprehensionScope): """Class representing an :class:`ast.GeneratorExp` node. >>> import astroid >>> node = astroid.extract_node('(thing for thing in things if thing)') >>> node <GeneratorExp l.1 at 0x7f23b2e4e400> """ _astroid_fields = ("elt", "generators") _other_other_fields = ("locals",) elt: NodeNG """The element that forms the output of the expression.""" def __init__( self, lineno: int, col_offset: int, parent: NodeNG, *, end_lineno: int | None, end_col_offset: int | None, ) -> None: self.locals = {} """A map of the name of a local variable to the node defining the local.""" self.generators: list[nodes.Comprehension] = [] """The generators that are looped through.""" super().__init__( lineno=lineno, col_offset=col_offset, end_lineno=end_lineno, end_col_offset=end_col_offset, parent=parent, ) def postinit(self, elt: NodeNG, generators: list[nodes.Comprehension]) -> None: self.elt = elt self.generators = generators def bool_value(self, context: InferenceContext | None = None) -> Literal[True]: """Determine the boolean value of this node. :returns: The boolean value of this node. For a :class:`GeneratorExp` this is always ``True``. """ return True def get_children(self): yield self.elt yield from self.generators class DictComp(ComprehensionScope): """Class representing an :class:`ast.DictComp` node. >>> import astroid >>> node = astroid.extract_node('{k:v for k, v in things if k > v}') >>> node <DictComp l.1 at 0x7f23b2e41d68> """ _astroid_fields = ("key", "value", "generators") _other_other_fields = ("locals",) key: NodeNG """What produces the keys.""" value: NodeNG """What produces the values.""" def __init__( self, lineno: int, col_offset: int, parent: NodeNG, *, end_lineno: int | None, end_col_offset: int | None, ) -> None: self.locals = {} """A map of the name of a local variable to the node defining the local.""" super().__init__( lineno=lineno, col_offset=col_offset, end_lineno=end_lineno, end_col_offset=end_col_offset, parent=parent, ) def postinit( self, key: NodeNG, value: NodeNG, generators: list[nodes.Comprehension] ) -> None: self.key = key self.value = value self.generators = generators def bool_value(self, context: InferenceContext | None = None): """Determine the boolean value of this node. :returns: The boolean value of this node. For a :class:`DictComp` this is always :class:`Uninferable`. :rtype: Uninferable """ return util.Uninferable def get_children(self): yield self.key yield self.value yield from self.generators class SetComp(ComprehensionScope): """Class representing an :class:`ast.SetComp` node. >>> import astroid >>> node = astroid.extract_node('{thing for thing in things if thing}') >>> node <SetComp l.1 at 0x7f23b2e41898> """ _astroid_fields = ("elt", "generators") _other_other_fields = ("locals",) elt: NodeNG """The element that forms the output of the expression.""" def __init__( self, lineno: int, col_offset: int, parent: NodeNG, *, end_lineno: int | None, end_col_offset: int | None, ) -> None: self.locals = {} """A map of the name of a local variable to the node defining the local.""" self.generators: list[nodes.Comprehension] = [] """The generators that are looped through.""" super().__init__( lineno=lineno, col_offset=col_offset, end_lineno=end_lineno, end_col_offset=end_col_offset, parent=parent, ) def postinit(self, elt: NodeNG, generators: list[nodes.Comprehension]) -> None: self.elt = elt self.generators = generators def bool_value(self, context: InferenceContext | None = None): """Determine the boolean value of this node. :returns: The boolean value of this node. For a :class:`SetComp` this is always :class:`Uninferable`. :rtype: Uninferable """ return util.Uninferable def get_children(self): yield self.elt yield from self.generators class ListComp(ComprehensionScope): """Class representing an :class:`ast.ListComp` node. >>> import astroid >>> node = astroid.extract_node('[thing for thing in things if thing]') >>> node <ListComp l.1 at 0x7f23b2e418d0> """ _astroid_fields = ("elt", "generators") _other_other_fields = ("locals",) elt: NodeNG """The element that forms the output of the expression.""" def __init__( self, lineno: int, col_offset: int, parent: NodeNG, *, end_lineno: int | None, end_col_offset: int | None, ) -> None: self.locals = {} """A map of the name of a local variable to the node defining it.""" self.generators: list[nodes.Comprehension] = [] """The generators that are looped through.""" super().__init__( lineno=lineno, col_offset=col_offset, end_lineno=end_lineno, end_col_offset=end_col_offset, parent=parent, ) def postinit(self, elt: NodeNG, generators: list[nodes.Comprehension]): self.elt = elt self.generators = generators def bool_value(self, context: InferenceContext | None = None): """Determine the boolean value of this node. :returns: The boolean value of this node. For a :class:`ListComp` this is always :class:`Uninferable`. :rtype: Uninferable """ return util.Uninferable def get_children(self): yield self.elt yield from self.generators def _infer_decorator_callchain(node): """Detect decorator call chaining and see if the end result is a static or a classmethod. """ if not isinstance(node, FunctionDef): return None if not node.parent: return None try: result = next(node.infer_call_result(node.parent), None) except InferenceError: return None if isinstance(result, bases.Instance): result = result._proxied if isinstance(result, ClassDef): if result.is_subtype_of("builtins.classmethod"): return "classmethod" if result.is_subtype_of("builtins.staticmethod"): return "staticmethod" if isinstance(result, FunctionDef): if not result.decorators: return None # Determine if this function is decorated with one of the builtin descriptors we want. for decorator in result.decorators.nodes: if isinstance(decorator, node_classes.Name): if decorator.name in BUILTIN_DESCRIPTORS: return decorator.name if ( isinstance(decorator, node_classes.Attribute) and isinstance(decorator.expr, node_classes.Name) and decorator.expr.name == "builtins" and decorator.attrname in BUILTIN_DESCRIPTORS ): return decorator.attrname return None class Lambda(_base_nodes.FilterStmtsBaseNode, LocalsDictNodeNG): """Class representing an :class:`ast.Lambda` node. >>> import astroid >>> node = astroid.extract_node('lambda arg: arg + 1') >>> node <Lambda.<lambda> l.1 at 0x7f23b2e41518> """ _astroid_fields: ClassVar[tuple[str, ...]] = ("args", "body") _other_other_fields: ClassVar[tuple[str, ...]] = ("locals",) name = "<lambda>" is_lambda = True special_attributes = FunctionModel() """The names of special attributes that this function has.""" args: Arguments """The arguments that the function takes.""" body: NodeNG """The contents of the function body.""" def implicit_parameters(self) -> Literal[0]: return 0 @property def type(self) -> Literal["method", "function"]: """Whether this is a method or function. :returns: 'method' if this is a method, 'function' otherwise. """ if self.args.arguments and self.args.arguments[0].name == "self": if self.parent and isinstance(self.parent.scope(), ClassDef): return "method" return "function" def __init__( self, lineno: int, col_offset: int, parent: NodeNG, *, end_lineno: int | None, end_col_offset: int | None, ): self.locals = {} """A map of the name of a local variable to the node defining it.""" self.instance_attrs: dict[str, list[NodeNG]] = {} super().__init__( lineno=lineno, col_offset=col_offset, end_lineno=end_lineno, end_col_offset=end_col_offset, parent=parent, ) def postinit(self, args: Arguments, body: NodeNG) -> None: self.args = args self.body = body def pytype(self) -> Literal["builtins.instancemethod", "builtins.function"]: """Get the name of the type that this node represents. :returns: The name of the type. """ if "method" in self.type: return "builtins.instancemethod" return "builtins.function" def display_type(self) -> str: """A human readable type of this node. :returns: The type of this node. :rtype: str """ if "method" in self.type: return "Method" return "Function" def callable(self) -> Literal[True]: """Whether this node defines something that is callable. :returns: Whether this defines something that is callable For a :class:`Lambda` this is always ``True``. """ return True def argnames(self) -> list[str]: """Get the names of each of the arguments, including that of the collections of variable-length arguments ("args", "kwargs", etc.), as well as positional-only and keyword-only arguments. :returns: The names of the arguments. :rtype: list(str) """ if self.args.arguments: # maybe None with builtin functions names = [elt.name for elt in self.args.arguments] else: names = [] return names def infer_call_result( self, caller: SuccessfulInferenceResult | None, context: InferenceContext | None = None, ) -> Iterator[InferenceResult]: """Infer what the function returns when called.""" return self.body.infer(context) def scope_lookup( self, node: LookupMixIn, name: str, offset: int = 0 ) -> tuple[LocalsDictNodeNG, list[NodeNG]]: """Lookup where the given names is assigned. :param node: The node to look for assignments up to. Any assignments after the given node are ignored. :param name: The name to find assignments for. :param offset: The line offset to filter statements up to. :returns: This scope node and the list of assignments associated to the given name according to the scope where it has been found (locals, globals or builtin). """ if (self.args.defaults and node in self.args.defaults) or ( self.args.kw_defaults and node in self.args.kw_defaults ): if not self.parent: raise ParentMissingError(target=self) frame = self.parent.frame() # line offset to avoid that def func(f=func) resolve the default # value to the defined function offset = -1 else: # check this is not used in function decorators frame = self return frame._scope_lookup(node, name, offset) def bool_value(self, context: InferenceContext | None = None) -> Literal[True]: """Determine the boolean value of this node. :returns: The boolean value of this node. For a :class:`Lambda` this is always ``True``. """ return True def get_children(self): yield self.args yield self.body def frame(self: _T, *, future: Literal[None, True] = None) -> _T: """The node's frame node. A frame node is a :class:`Module`, :class:`FunctionDef`, :class:`ClassDef` or :class:`Lambda`. :returns: The node itself. """ return self def getattr( self, name: str, context: InferenceContext | None = None ) -> list[NodeNG]: if not name: raise AttributeInferenceError(target=self, attribute=name, context=context) found_attrs = [] if name in self.instance_attrs: found_attrs = self.instance_attrs[name] if name in self.special_attributes: found_attrs.append(self.special_attributes.lookup(name)) if found_attrs: return found_attrs raise AttributeInferenceError(target=self, attribute=name) def _infer( self, context: InferenceContext | None = None, **kwargs: Any ) -> Generator[Lambda]: yield self def _get_yield_nodes_skip_functions(self): """A Lambda node can contain a Yield node in the body.""" yield from self.body._get_yield_nodes_skip_functions() class FunctionDef( _base_nodes.MultiLineBlockNode, _base_nodes.FilterStmtsBaseNode, _base_nodes.Statement, LocalsDictNodeNG, ): """Class representing an :class:`ast.FunctionDef`. >>> import astroid >>> node = astroid.extract_node(''' ... def my_func(arg): ... return arg + 1 ... ''') >>> node <FunctionDef.my_func l.2 at 0x7f23b2e71e10> """ _astroid_fields = ( "decorators", "args", "returns", "type_params", "doc_node", "body", ) _multi_line_block_fields = ("body",) returns = None decorators: node_classes.Decorators | None """The decorators that are applied to this method or function.""" doc_node: Const | None """The doc node associated with this node.""" args: Arguments """The arguments that the function takes.""" is_function = True """Whether this node indicates a function. For a :class:`FunctionDef` this is always ``True``. :type: bool """ type_annotation = None """If present, this will contain the type annotation passed by a type comment :type: NodeNG or None """ type_comment_args = None """ If present, this will contain the type annotation for arguments passed by a type comment """ type_comment_returns = None """If present, this will contain the return type annotation, passed by a type comment""" # attributes below are set by the builder module or by raw factories _other_fields = ("name", "position") _other_other_fields = ( "locals", "_type", "type_comment_returns", "type_comment_args", ) _type = None name = "<functiondef>" special_attributes = FunctionModel() """The names of special attributes that this function has.""" def __init__( self, name: str, lineno: int, col_offset: int, parent: NodeNG, *, end_lineno: int | None, end_col_offset: int | None, ) -> None: self.name = name """The name of the function.""" self.locals = {} """A map of the name of a local variable to the node defining it.""" self.body: list[NodeNG] = [] """The contents of the function body.""" self.type_params: list[nodes.TypeVar | nodes.ParamSpec | nodes.TypeVarTuple] = ( [] ) """PEP 695 (Python 3.12+) type params, e.g. first 'T' in def func[T]() -> T: ...""" self.instance_attrs: dict[str, list[NodeNG]] = {} super().__init__( lineno=lineno, col_offset=col_offset, end_lineno=end_lineno, end_col_offset=end_col_offset, parent=parent, ) if parent and not isinstance(parent, Unknown): frame = parent.frame() frame.set_local(name, self) def postinit( self, args: Arguments, body: list[NodeNG], decorators: node_classes.Decorators | None = None, returns=None, type_comment_returns=None, type_comment_args=None, *, position: Position | None = None, doc_node: Const | None = None, type_params: ( list[nodes.TypeVar | nodes.ParamSpec | nodes.TypeVarTuple] | None ) = None, ): """Do some setup after initialisation. :param args: The arguments that the function takes. :param body: The contents of the function body. :param decorators: The decorators that are applied to this method or function. :params type_comment_returns: The return type annotation passed via a type comment. :params type_comment_args: The args type annotation passed via a type comment. :params position: Position of function keyword(s) and name. :param doc_node: The doc node associated with this node. :param type_params: The type_params associated with this node. """ self.args = args self.body = body self.decorators = decorators self.returns = returns self.type_comment_returns = type_comment_returns self.type_comment_args = type_comment_args self.position = position self.doc_node = doc_node self.type_params = type_params or [] @cached_property def extra_decorators(self) -> list[node_classes.Call]: """The extra decorators that this function can have. Additional decorators are considered when they are used as assignments, as in ``method = staticmethod(method)``. The property will return all the callables that are used for decoration. """ if not self.parent or not isinstance(frame := self.parent.frame(), ClassDef): return [] decorators: list[node_classes.Call] = [] for assign in frame._assign_nodes_in_scope: if isinstance(assign.value, node_classes.Call) and isinstance( assign.value.func, node_classes.Name ): for assign_node in assign.targets: if not isinstance(assign_node, node_classes.AssignName): # Support only `name = callable(name)` continue if assign_node.name != self.name: # Interested only in the assignment nodes that # decorates the current method. continue try: meth = frame[self.name] except KeyError: continue else: # Must be a function and in the same frame as the # original method. if ( isinstance(meth, FunctionDef) and assign_node.frame() == frame ): decorators.append(assign.value) return decorators def pytype(self) -> Literal["builtins.instancemethod", "builtins.function"]: """Get the name of the type that this node represents. :returns: The name of the type. """ if "method" in self.type: return "builtins.instancemethod" return "builtins.function" def display_type(self) -> str: """A human readable type of this node. :returns: The type of this node. :rtype: str """ if "method" in self.type: return "Method" return "Function" def callable(self) -> Literal[True]: return True def argnames(self) -> list[str]: """Get the names of each of the arguments, including that of the collections of variable-length arguments ("args", "kwargs", etc.), as well as positional-only and keyword-only arguments. :returns: The names of the arguments. :rtype: list(str) """ if self.args.arguments: # maybe None with builtin functions names = [elt.name for elt in self.args.arguments] else: names = [] return names def getattr( self, name: str, context: InferenceContext | None = None ) -> list[NodeNG]: if not name: raise AttributeInferenceError(target=self, attribute=name, context=context) found_attrs = [] if name in self.instance_attrs: found_attrs = self.instance_attrs[name] if name in self.special_attributes: found_attrs.append(self.special_attributes.lookup(name)) if found_attrs: return found_attrs raise AttributeInferenceError(target=self, attribute=name) @cached_property def type(self) -> str: # pylint: disable=too-many-return-statements # noqa: C901 """The function type for this node. Possible values are: method, function, staticmethod, classmethod. """ for decorator in self.extra_decorators: if decorator.func.name in BUILTIN_DESCRIPTORS: return decorator.func.name if not self.parent: raise ParentMissingError(target=self) frame = self.parent.frame() type_name = "function" if isinstance(frame, ClassDef): if self.name == "__new__": return "classmethod" if self.name == "__init_subclass__": return "classmethod" if self.name == "__class_getitem__": return "classmethod" type_name = "method" if not self.decorators: return type_name for node in self.decorators.nodes: if isinstance(node, node_classes.Name): if node.name in BUILTIN_DESCRIPTORS: return node.name if ( isinstance(node, node_classes.Attribute) and isinstance(node.expr, node_classes.Name) and node.expr.name == "builtins" and node.attrname in BUILTIN_DESCRIPTORS ): return node.attrname if isinstance(node, node_classes.Call): # Handle the following case: # @some_decorator(arg1, arg2) # def func(...) # try: current = next(node.func.infer()) except (InferenceError, StopIteration): continue _type = _infer_decorator_callchain(current) if _type is not None: return _type try: for inferred in node.infer(): # Check to see if this returns a static or a class method. _type = _infer_decorator_callchain(inferred) if _type is not None: return _type if not isinstance(inferred, ClassDef): continue for ancestor in inferred.ancestors(): if not isinstance(ancestor, ClassDef): continue if ancestor.is_subtype_of("builtins.classmethod"): return "classmethod" if ancestor.is_subtype_of("builtins.staticmethod"): return "staticmethod" except InferenceError: pass return type_name @cached_property def fromlineno(self) -> int: """The first line that this node appears on in the source code. Can also return 0 if the line can not be determined. """ # lineno is the line number of the first decorator, we want the def # statement lineno. Similar to 'ClassDef.fromlineno' lineno = self.lineno or 0 if self.decorators is not None: lineno += sum( node.tolineno - (node.lineno or 0) + 1 for node in self.decorators.nodes ) return lineno or 0 @cached_property def blockstart_tolineno(self): """The line on which the beginning of this block ends. :type: int """ return self.args.tolineno def implicit_parameters(self) -> Literal[0, 1]: return 1 if self.is_bound() else 0 def block_range(self, lineno: int) -> tuple[int, int]: """Get a range from the given line number to where this node ends. :param lineno: Unused. :returns: The range of line numbers that this node belongs to, """ return self.fromlineno, self.tolineno def igetattr( self, name: str, context: InferenceContext | None = None ) -> Iterator[InferenceResult]: """Inferred getattr, which returns an iterator of inferred statements.""" try: return bases._infer_stmts(self.getattr(name, context), context, frame=self) except AttributeInferenceError as error: raise InferenceError( str(error), target=self, attribute=name, context=context ) from error def is_method(self) -> bool: """Check if this function node represents a method. :returns: Whether this is a method. """ # check we are defined in a ClassDef, because this is usually expected # (e.g. pylint...) when is_method() return True return ( self.type != "function" and self.parent is not None and isinstance(self.parent.frame(), ClassDef) ) def decoratornames(self, context: InferenceContext | None = None) -> set[str]: """Get the qualified names of each of the decorators on this function. :param context: An inference context that can be passed to inference functions :returns: The names of the decorators. """ result = set() decoratornodes = [] if self.decorators is not None: decoratornodes += self.decorators.nodes decoratornodes += self.extra_decorators for decnode in decoratornodes: try: for infnode in decnode.infer(context=context): result.add(infnode.qname()) except InferenceError: continue return result def is_bound(self) -> bool: """Check if the function is bound to an instance or class. :returns: Whether the function is bound to an instance or class. """ return self.type in {"method", "classmethod"} def is_abstract(self, pass_is_abstract=True, any_raise_is_abstract=False) -> bool: """Check if the method is abstract. A method is considered abstract if any of the following is true: * The only statement is 'raise NotImplementedError' * The only statement is 'raise <SomeException>' and any_raise_is_abstract is True * The only statement is 'pass' and pass_is_abstract is True * The method is annotated with abc.astractproperty/abc.abstractmethod :returns: Whether the method is abstract. """ if self.decorators: for node in self.decorators.nodes: try: inferred = next(node.infer()) except (InferenceError, StopIteration): continue if inferred and inferred.qname() in { "abc.abstractproperty", "abc.abstractmethod", }: return True for child_node in self.body: if isinstance(child_node, node_classes.Raise): if any_raise_is_abstract: return True if child_node.raises_not_implemented(): return True return pass_is_abstract and isinstance(child_node, node_classes.Pass) # empty function is the same as function with a single "pass" statement if pass_is_abstract: return True return False def is_generator(self) -> bool: """Check if this is a generator function. :returns: Whether this is a generator function. """ yields_without_lambdas = set(self._get_yield_nodes_skip_lambdas()) yields_without_functions = set(self._get_yield_nodes_skip_functions()) # Want an intersecting member that is neither in a lambda nor a function return bool(yields_without_lambdas & yields_without_functions) def _infer( self, context: InferenceContext | None = None, **kwargs: Any ) -> Generator[objects.Property | FunctionDef, None, InferenceErrorInfo]: from astroid import objects # pylint: disable=import-outside-toplevel if not self.decorators or not bases._is_property(self): yield self return InferenceErrorInfo(node=self, context=context) # When inferring a property, we instantiate a new `objects.Property` object, # which in turn, because it inherits from `FunctionDef`, sets itself in the locals # of the wrapping frame. This means that every time we infer a property, the locals # are mutated with a new instance of the property. To avoid this, we detect this # scenario and avoid passing the `parent` argument to the constructor. if not self.parent: raise ParentMissingError(target=self) parent_frame = self.parent.frame() property_already_in_parent_locals = self.name in parent_frame.locals and any( isinstance(val, objects.Property) for val in parent_frame.locals[self.name] ) # We also don't want to pass parent if the definition is within a Try node if isinstance( self.parent, (node_classes.Try, node_classes.If), ): property_already_in_parent_locals = True prop_func = objects.Property( function=self, name=self.name, lineno=self.lineno, parent=self.parent if not property_already_in_parent_locals else None, col_offset=self.col_offset, ) if property_already_in_parent_locals: prop_func.parent = self.parent prop_func.postinit(body=[], args=self.args, doc_node=self.doc_node) yield prop_func return InferenceErrorInfo(node=self, context=context) def infer_yield_result(self, context: InferenceContext | None = None): """Infer what the function yields when called :returns: What the function yields :rtype: iterable(NodeNG or Uninferable) or None """ for yield_ in self.nodes_of_class(node_classes.Yield): if yield_.value is None: const = node_classes.Const(None) const.parent = yield_ const.lineno = yield_.lineno yield const elif yield_.scope() == self: yield from yield_.value.infer(context=context) def infer_call_result( self, caller: SuccessfulInferenceResult | None, context: InferenceContext | None = None, ) -> Iterator[InferenceResult]: """Infer what the function returns when called.""" if self.is_generator(): if isinstance(self, AsyncFunctionDef): generator_cls: type[bases.Generator] = bases.AsyncGenerator else: generator_cls = bases.Generator result = generator_cls(self, generator_initial_context=context) yield result return # This is really a gigantic hack to work around metaclass generators # that return transient class-generating functions. Pylint's AST structure # cannot handle a base class object that is only used for calling __new__, # but does not contribute to the inheritance structure itself. We inject # a fake class into the hierarchy here for several well-known metaclass # generators, and filter it out later. if ( self.name == "with_metaclass" and caller is not None and self.args.args and len(self.args.args) == 1 and self.args.vararg is not None ): if isinstance(caller.args, Arguments): assert caller.args.args is not None metaclass = next(caller.args.args[0].infer(context), None) elif isinstance(caller.args, list): metaclass = next(caller.args[0].infer(context), None) else: raise TypeError( # pragma: no cover f"caller.args was neither Arguments nor list; got {type(caller.args)}" ) if isinstance(metaclass, ClassDef): try: class_bases = [ # Find the first non-None inferred base value next( b for b in arg.infer( context=context.clone() if context else context ) if not (isinstance(b, Const) and b.value is None) ) for arg in caller.args[1:] ] except StopIteration as e: raise InferenceError(node=caller.args[1:], context=context) from e new_class = ClassDef( name="temporary_class", lineno=0, col_offset=0, end_lineno=0, end_col_offset=0, parent=self, ) new_class.hide = True new_class.postinit( bases=[ base for base in class_bases if not isinstance(base, util.UninferableBase) ], body=[], decorators=None, metaclass=metaclass, ) yield new_class return returns = self._get_return_nodes_skip_functions() first_return = next(returns, None) if not first_return: if self.body: if self.is_abstract(pass_is_abstract=True, any_raise_is_abstract=True): yield util.Uninferable else: yield node_classes.Const(None) return raise InferenceError("The function does not have any return statements") for returnnode in itertools.chain((first_return,), returns): if returnnode.value is None: yield node_classes.Const(None) else: try: yield from returnnode.value.infer(context) except InferenceError: yield util.Uninferable def bool_value(self, context: InferenceContext | None = None) -> bool: """Determine the boolean value of this node. :returns: The boolean value of this node. For a :class:`FunctionDef` this is always ``True``. """ return True def get_children(self): if self.decorators is not None: yield self.decorators yield self.args if self.returns is not None: yield self.returns yield from self.type_params yield from self.body def scope_lookup( self, node: LookupMixIn, name: str, offset: int = 0 ) -> tuple[LocalsDictNodeNG, list[nodes.NodeNG]]: """Lookup where the given name is assigned.""" if name == "__class__": # __class__ is an implicit closure reference created by the compiler # if any methods in a class body refer to either __class__ or super. # In our case, we want to be able to look it up in the current scope # when `__class__` is being used. if self.parent and isinstance(frame := self.parent.frame(), ClassDef): return self, [frame] if (self.args.defaults and node in self.args.defaults) or ( self.args.kw_defaults and node in self.args.kw_defaults ): if not self.parent: raise ParentMissingError(target=self) frame = self.parent.frame() # line offset to avoid that def func(f=func) resolve the default # value to the defined function offset = -1 else: # check this is not used in function decorators frame = self return frame._scope_lookup(node, name, offset) def frame(self: _T, *, future: Literal[None, True] = None) -> _T: """The node's frame node. A frame node is a :class:`Module`, :class:`FunctionDef`, :class:`ClassDef` or :class:`Lambda`. :returns: The node itself. """ return self class AsyncFunctionDef(FunctionDef): """Class representing an :class:`ast.FunctionDef` node. A :class:`AsyncFunctionDef` is an asynchronous function created with the `async` keyword. >>> import astroid >>> node = astroid.extract_node(''' async def func(things): async for thing in things: print(thing) ''') >>> node <AsyncFunctionDef.func l.2 at 0x7f23b2e416d8> >>> node.body[0] <AsyncFor l.3 at 0x7f23b2e417b8> """ def _is_metaclass( klass: ClassDef, seen: set[str] | None = None, context: InferenceContext | None = None, ) -> bool: """Return if the given class can be used as a metaclass. """ if klass.name == "type": return True if seen is None: seen = set() for base in klass.bases: try: for baseobj in base.infer(context=context): baseobj_name = baseobj.qname() if baseobj_name in seen: continue seen.add(baseobj_name) if isinstance(baseobj, bases.Instance): # not abstract return False if baseobj is klass: continue if not isinstance(baseobj, ClassDef): continue if baseobj._type == "metaclass": return True if _is_metaclass(baseobj, seen, context=context): return True except InferenceError: continue return False def _class_type( klass: ClassDef, ancestors: set[str] | None = None, context: InferenceContext | None = None, ) -> Literal["class", "exception", "metaclass"]: """return a ClassDef node type to differ metaclass and exception from 'regular' classes """ # XXX we have to store ancestors in case we have an ancestor loop if klass._type is not None: return klass._type if _is_metaclass(klass, context=context): klass._type = "metaclass" elif klass.name.endswith("Exception"): klass._type = "exception" else: if ancestors is None: ancestors = set() klass_name = klass.qname() if klass_name in ancestors: # XXX we are in loop ancestors, and have found no type klass._type = "class" return "class" ancestors.add(klass_name) for base in klass.ancestors(recurs=False): name = _class_type(base, ancestors) if name != "class": if name == "metaclass" and klass._type != "metaclass": # don't propagate it if the current class # can't be a metaclass continue klass._type = base.type break if klass._type is None: klass._type = "class" return klass._type def get_wrapping_class(node): """Get the class that wraps the given node. We consider that a class wraps a node if the class is a parent for the said node. :returns: The class that wraps the given node :rtype: ClassDef or None """ klass = node.frame() while klass is not None and not isinstance(klass, ClassDef): if klass.parent is None: klass = None else: klass = klass.parent.frame() return klass class ClassDef( # pylint: disable=too-many-instance-attributes _base_nodes.FilterStmtsBaseNode, LocalsDictNodeNG, _base_nodes.Statement ): """Class representing an :class:`ast.ClassDef` node. >>> import astroid >>> node = astroid.extract_node(''' class Thing: def my_meth(self, arg): return arg + self.offset ''') >>> node <ClassDef.Thing l.2 at 0x7f23b2e9e748> """ # some of the attributes below are set by the builder module or # by a raw factories # a dictionary of class instances attributes _astroid_fields = ( "decorators", "bases", "keywords", "doc_node", "body", "type_params", ) # name decorators = None """The decorators that are applied to this class. :type: Decorators or None """ special_attributes = ClassModel() """The names of special attributes that this class has. :type: objectmodel.ClassModel """ _type: Literal["class", "exception", "metaclass"] | None = None _metaclass: NodeNG | None = None _metaclass_hack = False hide = False type = property( _class_type, doc=( "The class type for this node.\n\n" "Possible values are: class, metaclass, exception.\n\n" ":type: str" ), ) _other_fields = ("name", "is_dataclass", "position") _other_other_fields = ("locals", "_newstyle") _newstyle: bool | None = None def __init__( self, name: str, lineno: int, col_offset: int, parent: NodeNG, *, end_lineno: int | None, end_col_offset: int | None, ) -> None: self.instance_attrs: dict[str, NodeNG] = {} self.locals = {} """A map of the name of a local variable to the node defining it.""" self.keywords: list[node_classes.Keyword] = [] """The keywords given to the class definition. This is usually for :pep:`3115` style metaclass declaration. """ self.bases: list[SuccessfulInferenceResult] = [] """What the class inherits from.""" self.body: list[NodeNG] = [] """The contents of the class body.""" self.name = name """The name of the class.""" self.decorators = None """The decorators that are applied to this class.""" self.doc_node: Const | None = None """The doc node associated with this node.""" self.is_dataclass: bool = False """Whether this class is a dataclass.""" self.type_params: list[nodes.TypeVar | nodes.ParamSpec | nodes.TypeVarTuple] = ( [] ) """PEP 695 (Python 3.12+) type params, e.g. class MyClass[T]: ...""" super().__init__( lineno=lineno, col_offset=col_offset, end_lineno=end_lineno, end_col_offset=end_col_offset, parent=parent, ) if parent and not isinstance(parent, Unknown): parent.frame().set_local(name, self) for local_name, node in self.implicit_locals(): self.add_local_node(node, local_name) infer_binary_op: ClassVar[InferBinaryOp[ClassDef]] = ( protocols.instance_class_infer_binary_op ) def implicit_parameters(self) -> Literal[1]: return 1 def implicit_locals(self): """Get implicitly defined class definition locals. :returns: the the name and Const pair for each local :rtype: tuple(tuple(str, node_classes.Const), ...) """ locals_ = (("__module__", self.special_attributes.attr___module__),) # __qualname__ is defined in PEP3155 locals_ += ( ("__qualname__", self.special_attributes.attr___qualname__), ("__annotations__", self.special_attributes.attr___annotations__), ) return locals_ # pylint: disable=redefined-outer-name def postinit( self, bases: list[SuccessfulInferenceResult], body: list[NodeNG], decorators: node_classes.Decorators | None, newstyle: bool | None = None, metaclass: NodeNG | None = None, keywords: list[node_classes.Keyword] | None = None, *, position: Position | None = None, doc_node: Const | None = None, type_params: ( list[nodes.TypeVar | nodes.ParamSpec | nodes.TypeVarTuple] | None ) = None, ) -> None: if keywords is not None: self.keywords = keywords self.bases = bases self.body = body self.decorators = decorators self._newstyle = newstyle self._metaclass = metaclass self.position = position self.doc_node = doc_node self.type_params = type_params or [] def _newstyle_impl(self, context: InferenceContext | None = None): if context is None: context = InferenceContext() if self._newstyle is not None: return self._newstyle for base in self.ancestors(recurs=False, context=context): if base._newstyle_impl(context): self._newstyle = True break klass = self.declared_metaclass() # could be any callable, we'd need to infer the result of klass(name, # bases, dict). punt if it's not a class node. if klass is not None and isinstance(klass, ClassDef): self._newstyle = klass._newstyle_impl(context) if self._newstyle is None: self._newstyle = False return self._newstyle _newstyle = None newstyle = property( _newstyle_impl, doc=("Whether this is a new style class or not\n\n" ":type: bool or None"), ) @cached_property def blockstart_tolineno(self): """The line on which the beginning of this block ends. :type: int """ if self.bases: return self.bases[-1].tolineno return self.fromlineno def block_range(self, lineno: int) -> tuple[int, int]: """Get a range from the given line number to where this node ends. :param lineno: Unused. :returns: The range of line numbers that this node belongs to, """ return self.fromlineno, self.tolineno def pytype(self) -> Literal["builtins.type", "builtins.classobj"]: """Get the name of the type that this node represents. :returns: The name of the type. """ if self.newstyle: return "builtins.type" return "builtins.classobj" def display_type(self) -> str: """A human readable type of this node. :returns: The type of this node. :rtype: str """ return "Class" def callable(self) -> bool: """Whether this node defines something that is callable. :returns: Whether this defines something that is callable. For a :class:`ClassDef` this is always ``True``. """ return True def is_subtype_of(self, type_name, context: InferenceContext | None = None) -> bool: """Whether this class is a subtype of the given type. :param type_name: The name of the type of check against. :type type_name: str :returns: Whether this class is a subtype of the given type. """ if self.qname() == type_name: return True return any(anc.qname() == type_name for anc in self.ancestors(context=context)) def _infer_type_call(self, caller, context): try: name_node = next(caller.args[0].infer(context)) except StopIteration as e: raise InferenceError(node=caller.args[0], context=context) from e if isinstance(name_node, node_classes.Const) and isinstance( name_node.value, str ): name = name_node.value else: return util.Uninferable result = ClassDef( name, lineno=0, col_offset=0, end_lineno=0, end_col_offset=0, parent=Unknown(), ) # Get the bases of the class. try: class_bases = next(caller.args[1].infer(context)) except StopIteration as e: raise InferenceError(node=caller.args[1], context=context) from e if isinstance(class_bases, (node_classes.Tuple, node_classes.List)): bases = [] for base in class_bases.itered(): inferred = next(base.infer(context=context), None) if inferred: bases.append( node_classes.EvaluatedObject(original=base, value=inferred) ) result.bases = bases else: # There is currently no AST node that can represent an 'unknown' # node (Uninferable is not an AST node), therefore we simply return Uninferable here # although we know at least the name of the class. return util.Uninferable # Get the members of the class try: members = next(caller.args[2].infer(context)) except (InferenceError, StopIteration): members = None if members and isinstance(members, node_classes.Dict): for attr, value in members.items: if isinstance(attr, node_classes.Const) and isinstance(attr.value, str): result.locals[attr.value] = [value] result.parent = caller.parent return result def infer_call_result( self, caller: SuccessfulInferenceResult | None, context: InferenceContext | None = None, ) -> Iterator[InferenceResult]: """infer what a class is returning when called""" if self.is_subtype_of("builtins.type", context) and len(caller.args) == 3: result = self._infer_type_call(caller, context) yield result return dunder_call = None try: metaclass = self.metaclass(context=context) if metaclass is not None: # Only get __call__ if it's defined locally for the metaclass. # Otherwise we will find ObjectModel.__call__ which will # return an instance of the metaclass. Instantiating the class is # handled later. if "__call__" in metaclass.locals: dunder_call = next(metaclass.igetattr("__call__", context)) except (AttributeInferenceError, StopIteration): pass if dunder_call and dunder_call.qname() != "builtins.type.__call__": # Call type.__call__ if not set metaclass # (since type is the default metaclass) context = bind_context_to_node(context, self) context.callcontext.callee = dunder_call yield from dunder_call.infer_call_result(caller, context) else: yield self.instantiate_class() def scope_lookup( self, node: LookupMixIn, name: str, offset: int = 0 ) -> tuple[LocalsDictNodeNG, list[nodes.NodeNG]]: """Lookup where the given name is assigned. :param node: The node to look for assignments up to. Any assignments after the given node are ignored. :param name: The name to find assignments for. :param offset: The line offset to filter statements up to. :returns: This scope node and the list of assignments associated to the given name according to the scope where it has been found (locals, globals or builtin). """ # If the name looks like a builtin name, just try to look # into the upper scope of this class. We might have a # decorator that it's poorly named after a builtin object # inside this class. lookup_upper_frame = ( isinstance(node.parent, node_classes.Decorators) and name in AstroidManager().builtins_module ) if ( any( node == base or base.parent_of(node) and not self.type_params for base in self.bases ) or lookup_upper_frame ): # Handle the case where we have either a name # in the bases of a class, which exists before # the actual definition or the case where we have # a Getattr node, with that name. # # name = ... # class A(name): # def name(self): ... # # import name # class A(name.Name): # def name(self): ... if not self.parent: raise ParentMissingError(target=self) frame = self.parent.frame() # line offset to avoid that class A(A) resolve the ancestor to # the defined class offset = -1 else: frame = self return frame._scope_lookup(node, name, offset) @property def basenames(self): """The names of the parent classes Names are given in the order they appear in the class definition. :type: list(str) """ return [bnode.as_string() for bnode in self.bases] def ancestors( self, recurs: bool = True, context: InferenceContext | None = None ) -> Generator[ClassDef]: """Iterate over the base classes in prefixed depth first order. :param recurs: Whether to recurse or return direct ancestors only. :returns: The base classes """ # FIXME: should be possible to choose the resolution order # FIXME: inference make infinite loops possible here yielded = {self} if context is None: context = InferenceContext() if not self.bases and self.qname() != "builtins.object": # This should always be a ClassDef (which we don't assert for) yield builtin_lookup("object")[1][0] # type: ignore[misc] return for stmt in self.bases: with context.restore_path(): try: for baseobj in stmt.infer(context): if not isinstance(baseobj, ClassDef): if isinstance(baseobj, bases.Instance): baseobj = baseobj._proxied else: continue if not baseobj.hide: if baseobj in yielded: continue yielded.add(baseobj) yield baseobj if not recurs: continue for grandpa in baseobj.ancestors(recurs=True, context=context): if grandpa is self: # This class is the ancestor of itself. break if grandpa in yielded: continue yielded.add(grandpa) yield grandpa except InferenceError: continue def local_attr_ancestors(self, name, context: InferenceContext | None = None): """Iterate over the parents that define the given name. :param name: The name to find definitions for. :type name: str :returns: The parents that define the given name. :rtype: iterable(NodeNG) """ # Look up in the mro if we can. This will result in the # attribute being looked up just as Python does it. try: ancestors: Iterable[ClassDef] = self.mro(context)[1:] except MroError: # Fallback to use ancestors, we can't determine # a sane MRO. ancestors = self.ancestors(context=context) for astroid in ancestors: if name in astroid: yield astroid def instance_attr_ancestors(self, name, context: InferenceContext | None = None): """Iterate over the parents that define the given name as an attribute. :param name: The name to find definitions for. :type name: str :returns: The parents that define the given name as an instance attribute. :rtype: iterable(NodeNG) """ for astroid in self.ancestors(context=context): if name in astroid.instance_attrs: yield astroid def has_base(self, node) -> bool: """Whether this class directly inherits from the given node. :param node: The node to check for. :type node: NodeNG :returns: Whether this class directly inherits from the given node. """ return node in self.bases def local_attr(self, name, context: InferenceContext | None = None): """Get the list of assign nodes associated to the given name. Assignments are looked for in both this class and in parents. :returns: The list of assignments to the given name. :rtype: list(NodeNG) :raises AttributeInferenceError: If no attribute with this name can be found in this class or parent classes. """ result = [] if name in self.locals: result = self.locals[name] else: class_node = next(self.local_attr_ancestors(name, context), None) if class_node: result = class_node.locals[name] result = [n for n in result if not isinstance(n, node_classes.DelAttr)] if result: return result raise AttributeInferenceError(target=self, attribute=name, context=context) def instance_attr(self, name, context: InferenceContext | None = None): """Get the list of nodes associated to the given attribute name. Assignments are looked for in both this class and in parents. :returns: The list of assignments to the given name. :rtype: list(NodeNG) :raises AttributeInferenceError: If no attribute with this name can be found in this class or parent classes. """ # Return a copy, so we don't modify self.instance_attrs, # which could lead to infinite loop. values = list(self.instance_attrs.get(name, [])) # get all values from parents for class_node in self.instance_attr_ancestors(name, context): values += class_node.instance_attrs[name] values = [n for n in values if not isinstance(n, node_classes.DelAttr)] if values: return values raise AttributeInferenceError(target=self, attribute=name, context=context) def instantiate_class(self) -> bases.Instance: """Get an :class:`Instance` of the :class:`ClassDef` node. :returns: An :class:`Instance` of the :class:`ClassDef` node """ from astroid import objects # pylint: disable=import-outside-toplevel try: if any(cls.name in EXCEPTION_BASE_CLASSES for cls in self.mro()): # Subclasses of exceptions can be exception instances return objects.ExceptionInstance(self) except MroError: pass return bases.Instance(self) def getattr( self, name: str, context: InferenceContext | None = None, class_context: bool = True, ) -> list[InferenceResult]: """Get an attribute from this class, using Python's attribute semantic. This method doesn't look in the :attr:`instance_attrs` dictionary since it is done by an :class:`Instance` proxy at inference time. It may return an :class:`Uninferable` object if the attribute has not been found, but a ``__getattr__`` or ``__getattribute__`` method is defined. If ``class_context`` is given, then it is considered that the attribute is accessed from a class context, e.g. ClassDef.attribute, otherwise it might have been accessed from an instance as well. If ``class_context`` is used in that case, then a lookup in the implicit metaclass and the explicit metaclass will be done. :param name: The attribute to look for. :param class_context: Whether the attribute can be accessed statically. :returns: The attribute. :raises AttributeInferenceError: If the attribute cannot be inferred. """ if not name: raise AttributeInferenceError(target=self, attribute=name, context=context) # don't modify the list in self.locals! values: list[InferenceResult] = list(self.locals.get(name, [])) for classnode in self.ancestors(recurs=True, context=context): values += classnode.locals.get(name, []) if name in self.special_attributes and class_context and not values: result = [self.special_attributes.lookup(name)] if name == "__bases__": # Need special treatment, since they are mutable # and we need to return all the values. result += values return result if class_context: values += self._metaclass_lookup_attribute(name, context) # Remove AnnAssigns without value, which are not attributes in the purest sense. for value in values.copy(): if isinstance(value, node_classes.AssignName): stmt = value.statement() if isinstance(stmt, node_classes.AnnAssign) and stmt.value is None: values.pop(values.index(value)) if not values: raise AttributeInferenceError(target=self, attribute=name, context=context) return values @lru_cache(maxsize=1024) # noqa def _metaclass_lookup_attribute(self, name, context): """Search the given name in the implicit and the explicit metaclass.""" attrs = set() implicit_meta = self.implicit_metaclass() context = copy_context(context) metaclass = self.metaclass(context=context) for cls in (implicit_meta, metaclass): if cls and cls != self and isinstance(cls, ClassDef): cls_attributes = self._get_attribute_from_metaclass(cls, name, context) attrs.update(set(cls_attributes)) return attrs def _get_attribute_from_metaclass(self, cls, name, context): from astroid import objects # pylint: disable=import-outside-toplevel try: attrs = cls.getattr(name, context=context, class_context=True) except AttributeInferenceError: return for attr in bases._infer_stmts(attrs, context, frame=cls): if not isinstance(attr, FunctionDef): yield attr continue if isinstance(attr, objects.Property): yield attr continue if attr.type == "classmethod": # If the method is a classmethod, then it will # be bound to the metaclass, not to the class # from where the attribute is retrieved. # get_wrapping_class could return None, so just # default to the current class. frame = get_wrapping_class(attr) or self yield bases.BoundMethod(attr, frame) elif attr.type == "staticmethod": yield attr else: yield bases.BoundMethod(attr, self) def igetattr( self, name: str, context: InferenceContext | None = None, class_context: bool = True, ) -> Iterator[InferenceResult]: """Infer the possible values of the given variable. :param name: The name of the variable to infer. :returns: The inferred possible values. """ from astroid import objects # pylint: disable=import-outside-toplevel # set lookup name since this is necessary to infer on import nodes for # instance context = copy_context(context) context.lookupname = name metaclass = self.metaclass(context=context) try: attributes = self.getattr(name, context, class_context=class_context) # If we have more than one attribute, make sure that those starting from # the second one are from the same scope. This is to account for modifications # to the attribute happening *after* the attribute's definition (e.g. AugAssigns on lists) if len(attributes) > 1: first_attr, attributes = attributes[0], attributes[1:] first_scope = first_attr.parent.scope() attributes = [first_attr] + [ attr for attr in attributes if attr.parent and attr.parent.scope() == first_scope ] functions = [attr for attr in attributes if isinstance(attr, FunctionDef)] setter = None for function in functions: dec_names = function.decoratornames(context=context) for dec_name in dec_names: if dec_name is util.Uninferable: continue if dec_name.split(".")[-1] == "setter": setter = function if setter: break if functions: # Prefer only the last function, unless a property is involved. last_function = functions[-1] attributes = [ a for a in attributes if a not in functions or a is last_function or bases._is_property(a) ] for inferred in bases._infer_stmts(attributes, context, frame=self): # yield Uninferable object instead of descriptors when necessary if not isinstance(inferred, node_classes.Const) and isinstance( inferred, bases.Instance ): try: inferred._proxied.getattr("__get__", context) except AttributeInferenceError: yield inferred else: yield util.Uninferable elif isinstance(inferred, objects.Property): function = inferred.function if not class_context: if not context.callcontext and not setter: context.callcontext = CallContext( args=function.args.arguments, callee=function ) # Through an instance so we can solve the property yield from function.infer_call_result( caller=self, context=context ) # If we're in a class context, we need to determine if the property # was defined in the metaclass (a derived class must be a subclass of # the metaclass of all its bases), in which case we can resolve the # property. If not, i.e. the property is defined in some base class # instead, then we return the property object elif metaclass and function.parent.scope() is metaclass: # Resolve a property as long as it is not accessed through # the class itself. yield from function.infer_call_result( caller=self, context=context ) else: yield inferred else: yield function_to_method(inferred, self) except AttributeInferenceError as error: if not name.startswith("__") and self.has_dynamic_getattr(context): # class handle some dynamic attributes, return a Uninferable object yield util.Uninferable else: raise InferenceError( str(error), target=self, attribute=name, context=context ) from error def has_dynamic_getattr(self, context: InferenceContext | None = None) -> bool: """Check if the class has a custom __getattr__ or __getattribute__. If any such method is found and it is not from builtins, nor from an extension module, then the function will return True. :returns: Whether the class has a custom __getattr__ or __getattribute__. """ def _valid_getattr(node): root = node.root() return root.name != "builtins" and getattr(root, "pure_python", None) try: return _valid_getattr(self.getattr("__getattr__", context)[0]) except AttributeInferenceError: # if self.newstyle: XXX cause an infinite recursion error try: getattribute = self.getattr("__getattribute__", context)[0] return _valid_getattr(getattribute) except AttributeInferenceError: pass return False def getitem(self, index, context: InferenceContext | None = None): """Return the inference of a subscript. This is basically looking up the method in the metaclass and calling it. :returns: The inferred value of a subscript to this class. :rtype: NodeNG :raises AstroidTypeError: If this class does not define a ``__getitem__`` method. """ try: methods = lookup(self, "__getitem__", context=context) except AttributeInferenceError as exc: if isinstance(self, ClassDef): # subscripting a class definition may be # achieved thanks to __class_getitem__ method # which is a classmethod defined in the class # that supports subscript and not in the metaclass try: methods = self.getattr("__class_getitem__") # Here it is assumed that the __class_getitem__ node is # a FunctionDef. One possible improvement would be to deal # with more generic inference. except AttributeInferenceError: raise AstroidTypeError(node=self, context=context) from exc else: raise AstroidTypeError(node=self, context=context) from exc method = methods[0] # Create a new callcontext for providing index as an argument. new_context = bind_context_to_node(context, self) new_context.callcontext = CallContext(args=[index], callee=method) try: return next(method.infer_call_result(self, new_context), util.Uninferable) except AttributeError: # Starting with python3.9, builtin types list, dict etc... # are subscriptable thanks to __class_getitem___ classmethod. # However in such case the method is bound to an EmptyNode and # EmptyNode doesn't have infer_call_result method yielding to # AttributeError if ( isinstance(method, node_classes.EmptyNode) and self.pytype() == "builtins.type" ): return self raise except InferenceError: return util.Uninferable def methods(self): """Iterate over all of the method defined in this class and its parents. :returns: The methods defined on the class. :rtype: iterable(FunctionDef) """ done = {} for astroid in itertools.chain(iter((self,)), self.ancestors()): for meth in astroid.mymethods(): if meth.name in done: continue done[meth.name] = None yield meth def mymethods(self): """Iterate over all of the method defined in this class only. :returns: The methods defined on the class. :rtype: iterable(FunctionDef) """ for member in self.values(): if isinstance(member, FunctionDef): yield member def implicit_metaclass(self): """Get the implicit metaclass of the current class. For newstyle classes, this will return an instance of builtins.type. For oldstyle classes, it will simply return None, since there's no implicit metaclass there. :returns: The metaclass. :rtype: builtins.type or None """ if self.newstyle: return builtin_lookup("type")[1][0] return None def declared_metaclass( self, context: InferenceContext | None = None ) -> SuccessfulInferenceResult | None: """Return the explicit declared metaclass for the current class. An explicit declared metaclass is defined either by passing the ``metaclass`` keyword argument in the class definition line (Python 3) or (Python 2) by having a ``__metaclass__`` class attribute, or if there are no explicit bases but there is a global ``__metaclass__`` variable. :returns: The metaclass of this class, or None if one could not be found. """ for base in self.bases: try: for baseobj in base.infer(context=context): if isinstance(baseobj, ClassDef) and baseobj.hide: self._metaclass = baseobj._metaclass self._metaclass_hack = True break except InferenceError: pass if self._metaclass: # Expects this from Py3k TreeRebuilder try: return next( node for node in self._metaclass.infer(context=context) if not isinstance(node, util.UninferableBase) ) except (InferenceError, StopIteration): return None return None def _find_metaclass( self, seen: set[ClassDef] | None = None, context: InferenceContext | None = None ) -> SuccessfulInferenceResult | None: if seen is None: seen = set() seen.add(self) klass = self.declared_metaclass(context=context) if klass is None: for parent in self.ancestors(context=context): if parent not in seen: klass = parent._find_metaclass(seen) if klass is not None: break return klass def metaclass( self, context: InferenceContext | None = None ) -> SuccessfulInferenceResult | None: """Get the metaclass of this class. If this class does not define explicitly a metaclass, then the first defined metaclass in ancestors will be used instead. :returns: The metaclass of this class. """ return self._find_metaclass(context=context) def has_metaclass_hack(self): return self._metaclass_hack def _islots(self): """Return an iterator with the inferred slots.""" if "__slots__" not in self.locals: return None for slots in self.igetattr("__slots__"): # check if __slots__ is a valid type for meth in ITER_METHODS: try: slots.getattr(meth) break except AttributeInferenceError: continue else: continue if isinstance(slots, node_classes.Const): # a string. Ignore the following checks, # but yield the node, only if it has a value if slots.value: yield slots continue if not hasattr(slots, "itered"): # we can't obtain the values, maybe a .deque? continue if isinstance(slots, node_classes.Dict): values = [item[0] for item in slots.items] else: values = slots.itered() if isinstance(values, util.UninferableBase): continue if not values: # Stop the iteration, because the class # has an empty list of slots. return values for elt in values: try: for inferred in elt.infer(): if not isinstance( inferred, node_classes.Const ) or not isinstance(inferred.value, str): continue if not inferred.value: continue yield inferred except InferenceError: continue return None def _slots(self): if not self.newstyle: raise NotImplementedError( "The concept of slots is undefined for old-style classes." ) slots = self._islots() try: first = next(slots) except StopIteration as exc: # The class doesn't have a __slots__ definition or empty slots. if exc.args and exc.args[0] not in ("", None): return exc.args[0] return None return [first, *slots] # Cached, because inferring them all the time is expensive @cached_property def _all_slots(self): """Get all the slots for this node. :returns: The names of slots for this class. If the class doesn't define any slot, through the ``__slots__`` variable, then this function will return a None. Also, it will return None in the case the slots were not inferred. :rtype: list(str) or None """ def grouped_slots( mro: list[ClassDef], ) -> Iterator[node_classes.NodeNG | None]: for cls in mro: # Not interested in object, since it can't have slots. if cls.qname() == "builtins.object": continue try: cls_slots = cls._slots() except NotImplementedError: continue if cls_slots is not None: yield from cls_slots else: yield None if not self.newstyle: raise NotImplementedError( "The concept of slots is undefined for old-style classes." ) try: mro = self.mro() except MroError as e: raise NotImplementedError( "Cannot get slots while parsing mro fails." ) from e slots = list(grouped_slots(mro)) if not all(slot is not None for slot in slots): return None return sorted(set(slots), key=lambda item: item.value) def slots(self): return self._all_slots def _inferred_bases(self, context: InferenceContext | None = None): # Similar with .ancestors, but the difference is when one base is inferred, # only the first object is wanted. That's because # we aren't interested in superclasses, as in the following # example: # # class SomeSuperClass(object): pass # class SomeClass(SomeSuperClass): pass # class Test(SomeClass): pass # # Inferring SomeClass from the Test's bases will give # us both SomeClass and SomeSuperClass, but we are interested # only in SomeClass. if context is None: context = InferenceContext() if not self.bases and self.qname() != "builtins.object": yield builtin_lookup("object")[1][0] return for stmt in self.bases: try: # Find the first non-None inferred base value baseobj = next( b for b in stmt.infer(context=context.clone()) if not (isinstance(b, Const) and b.value is None) ) except (InferenceError, StopIteration): continue if isinstance(baseobj, bases.Instance): baseobj = baseobj._proxied if not isinstance(baseobj, ClassDef): continue if not baseobj.hide: yield baseobj else: yield from baseobj.bases def _compute_mro(self, context: InferenceContext | None = None): if self.qname() == "builtins.object": return [self] inferred_bases = list(self._inferred_bases(context=context)) bases_mro = [] for base in inferred_bases: if base is self: continue try: mro = base._compute_mro(context=context) bases_mro.append(mro) except NotImplementedError: # Some classes have in their ancestors both newstyle and # old style classes. For these we can't retrieve the .mro, # although in Python it's possible, since the class we are # currently working is in fact new style. # So, we fallback to ancestors here. ancestors = list(base.ancestors(context=context)) bases_mro.append(ancestors) unmerged_mro: list[list[ClassDef]] = [[self], *bases_mro, inferred_bases] unmerged_mro = clean_duplicates_mro(unmerged_mro, self, context) clean_typing_generic_mro(unmerged_mro) return _c3_merge(unmerged_mro, self, context) def mro(self, context: InferenceContext | None = None) -> list[ClassDef]: """Get the method resolution order, using C3 linearization. :returns: The list of ancestors, sorted by the mro. :rtype: list(NodeNG) :raises DuplicateBasesError: Duplicate bases in the same class base :raises InconsistentMroError: A class' MRO is inconsistent """ return self._compute_mro(context=context) def bool_value(self, context: InferenceContext | None = None) -> Literal[True]: """Determine the boolean value of this node. :returns: The boolean value of this node. For a :class:`ClassDef` this is always ``True``. """ return True def get_children(self): if self.decorators is not None: yield self.decorators yield from self.bases if self.keywords is not None: yield from self.keywords yield from self.type_params yield from self.body @cached_property def _assign_nodes_in_scope(self): children_assign_nodes = ( child_node._assign_nodes_in_scope for child_node in self.body ) return list(itertools.chain.from_iterable(children_assign_nodes)) def frame(self: _T, *, future: Literal[None, True] = None) -> _T: """The node's frame node. A frame node is a :class:`Module`, :class:`FunctionDef`, :class:`ClassDef` or :class:`Lambda`. :returns: The node itself. """ return self def _infer( self, context: InferenceContext | None = None, **kwargs: Any ) -> Generator[ClassDef]: yield self