astroid/nodes/scoped_nodes/mixin.py

# 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 mixin classes for scoped nodes."""

from __future__ import annotations

import sys
from typing import TYPE_CHECKING, overload

from astroid.exceptions import ParentMissingError
from astroid.filter_statements import _filter_stmts
from astroid.nodes import _base_nodes, scoped_nodes
from astroid.nodes.scoped_nodes.utils import builtin_lookup
from astroid.typing import InferenceResult, SuccessfulInferenceResult

if sys.version_info >= (3, 11):
    from typing import Self
else:
    from typing_extensions import Self
if TYPE_CHECKING:
    from astroid import nodes


class LocalsDictNodeNG(_base_nodes.LookupMixIn):
    """this class provides locals handling common to Module, FunctionDef
    and ClassDef nodes, including a dict like interface for direct access
    to locals information
    """

    # attributes below are set by the builder module or by raw factories
    locals: dict[str, list[InferenceResult]]
    """A map of the name of a local variable to the node defining the local."""

    def qname(self) -> str:
        """Get the 'qualified' name of the node.

        For example: module.name, module.class.name ...

        :returns: The qualified name.
        :rtype: str
        """
        # pylint: disable=no-member; github.com/pylint-dev/astroid/issues/278
        if self.parent is None:
            return self.name
        try:
            return f"{self.parent.frame().qname()}.{self.name}"
        except ParentMissingError:
            return self.name

    def scope(self) -> Self:
        """The first parent node defining a new scope.

        :returns: The first parent scope node.
        :rtype: Module or FunctionDef or ClassDef or Lambda or GenExpr
        """
        return self

    def scope_lookup(
        self, node: _base_nodes.LookupMixIn, name: str, offset: int = 0
    ) -> tuple[LocalsDictNodeNG, list[nodes.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).
        """
        raise NotImplementedError

    def _scope_lookup(
        self, node: _base_nodes.LookupMixIn, name: str, offset: int = 0
    ) -> tuple[LocalsDictNodeNG, list[nodes.NodeNG]]:
        """XXX method for interfacing the scope lookup"""
        try:
            stmts = _filter_stmts(node, self.locals[name], self, offset)
        except KeyError:
            stmts = ()
        if stmts:
            return self, stmts

        # Handle nested scopes: since class names do not extend to nested
        # scopes (e.g., methods), we find the next enclosing non-class scope
        pscope = self.parent and self.parent.scope()
        while pscope is not None:
            if not isinstance(pscope, scoped_nodes.ClassDef):
                return pscope.scope_lookup(node, name)
            pscope = pscope.parent and pscope.parent.scope()

        # self is at the top level of a module, or is enclosed only by ClassDefs
        return builtin_lookup(name)

    def set_local(self, name: str, stmt: nodes.NodeNG) -> None:
        """Define that the given name is declared in the given statement node.

        .. seealso:: :meth:`scope`

        :param name: The name that is being defined.

        :param stmt: The statement that defines the given name.
        """
        # assert not stmt in self.locals.get(name, ()), (self, stmt)
        self.locals.setdefault(name, []).append(stmt)

    __setitem__ = set_local

    def _append_node(self, child: nodes.NodeNG) -> None:
        """append a child, linking it in the tree"""
        # pylint: disable=no-member; depending by the class
        # which uses the current class as a mixin or base class.
        # It's rewritten in 2.0, so it makes no sense for now
        # to spend development time on it.
        self.body.append(child)  # type: ignore[attr-defined]
        child.parent = self

    @overload
    def add_local_node(
        self, child_node: nodes.ClassDef, name: str | None = ...
    ) -> None: ...

    @overload
    def add_local_node(self, child_node: nodes.NodeNG, name: str) -> None: ...

    def add_local_node(self, child_node: nodes.NodeNG, name: str | None = None) -> None:
        """Append a child that should alter the locals of this scope node.

        :param child_node: The child node that will alter locals.

        :param name: The name of the local that will be altered by
            the given child node.
        """
        if name != "__class__":
            # add __class__ node as a child will cause infinite recursion later!
            self._append_node(child_node)
        self.set_local(name or child_node.name, child_node)  # type: ignore[attr-defined]

    def __getitem__(self, item: str) -> SuccessfulInferenceResult:
        """The first node the defines the given local.

        :param item: The name of the locally defined object.

        :raises KeyError: If the name is not defined.
        """
        return self.locals[item][0]

    def __iter__(self):
        """Iterate over the names of locals defined in this scoped node.

        :returns: The names of the defined locals.
        :rtype: iterable(str)
        """
        return iter(self.keys())

    def keys(self):
        """The names of locals defined in this scoped node.

        :returns: The names of the defined locals.
        :rtype: list(str)
        """
        return list(self.locals.keys())

    def values(self):
        """The nodes that define the locals in this scoped node.

        :returns: The nodes that define locals.
        :rtype: list(NodeNG)
        """
        # pylint: disable=consider-using-dict-items
        # It look like this class override items/keys/values,
        # probably not worth the headache
        return [self[key] for key in self.keys()]

    def items(self):
        """Get the names of the locals and the node that defines the local.

        :returns: The names of locals and their associated node.
        :rtype: list(tuple(str, NodeNG))
        """
        return list(zip(self.keys(), self.values()))

    def __contains__(self, name) -> bool:
        """Check if a local is defined in this scope.

        :param name: The name of the local to check for.
        :type name: str

        :returns: Whether this node has a local of the given name,
        """
        return name in self.locals


class ComprehensionScope(LocalsDictNodeNG):
    """Scoping for different types of comprehensions."""

    scope_lookup = LocalsDictNodeNG._scope_lookup

    generators: list[nodes.Comprehension]
    """The generators that are looped through."""