[Backport 2.13.x] Revert CallContext change since it caused a RecursionError regression (#2000)

ChangeLog

@@ -12,6 +12,8 @@ What's New in astroid 2.13.5?
 =============================
 Release date: TBA
 
+* Revert ``CallContext`` change as it caused a ``RecursionError`` regression.
+
 
 
 What's New in astroid 2.13.4?

astroid/brain/brain_typing.py

@@ -28,6 +28,7 @@
     Const,
     JoinedStr,
     Name,
+    NodeNG,
     Subscript,
     Tuple,
 )
@@ -379,6 +380,36 @@ def infer_special_alias(
     return iter([class_def])
 
 
+def _looks_like_typing_cast(node: Call) -> bool:
+    return isinstance(node, Call) and (
+        isinstance(node.func, Name)
+        and node.func.name == "cast"
+        or isinstance(node.func, Attribute)
+        and node.func.attrname == "cast"
+    )
+
+
+def infer_typing_cast(
+    node: Call, ctx: context.InferenceContext | None = None
+) -> Iterator[NodeNG]:
+    """Infer call to cast() returning same type as casted-from var."""
+    if not isinstance(node.func, (Name, Attribute)):
+        raise UseInferenceDefault
+
+    try:
+        func = next(node.func.infer(context=ctx))
+    except (InferenceError, StopIteration) as exc:
+        raise UseInferenceDefault from exc
+    if (
+        not isinstance(func, FunctionDef)
+        or func.qname() != "typing.cast"
+        or len(node.args) != 2
+    ):
+        raise UseInferenceDefault
+
+    return node.args[1].infer(context=ctx)
+
+
 AstroidManager().register_transform(
     Call,
     inference_tip(infer_typing_typevar_or_newtype),
@@ -387,6 +418,9 @@ def infer_special_alias(
 AstroidManager().register_transform(
     Subscript, inference_tip(infer_typing_attr), _looks_like_typing_subscript
 )
+AstroidManager().register_transform(
+    Call, inference_tip(infer_typing_cast), _looks_like_typing_cast
+)
 
 if PY39_PLUS:
     AstroidManager().register_transform(

astroid/context.py

@@ -161,14 +161,13 @@ def __str__(self) -> str:
 class CallContext:
     """Holds information for a call site."""
 
-    __slots__ = ("args", "keywords", "callee", "parent_call_context")
+    __slots__ = ("args", "keywords", "callee")
 
     def __init__(
         self,
         args: list[NodeNG],
         keywords: list[Keyword] | None = None,
         callee: NodeNG | None = None,
-        parent_call_context: CallContext | None = None,
     ):
         self.args = args  # Call positional arguments
         if keywords:
@@ -177,9 +176,6 @@ def __init__(
             arg_value_pairs = []
         self.keywords = arg_value_pairs  # Call keyword arguments
         self.callee = callee  # Function being called
-        self.parent_call_context = (
-            parent_call_context  # Parent CallContext for nested calls
-        )
 
 
 def copy_context(context: InferenceContext | None) -> InferenceContext:

astroid/inference.py

@@ -273,10 +273,7 @@ def infer_call(
         try:
             if hasattr(callee, "infer_call_result"):
                 callcontext.callcontext = CallContext(
-                    args=self.args,
-                    keywords=self.keywords,
-                    callee=callee,
-                    parent_call_context=callcontext.callcontext,
+                    args=self.args, keywords=self.keywords, callee=callee
                 )
                 yield from callee.infer_call_result(caller=self, context=callcontext)
         except InferenceError:

astroid/protocols.py

@@ -470,7 +470,7 @@ def arguments_assigned_stmts(
         # reset call context/name
         callcontext = context.callcontext
         context = copy_context(context)
-        context.callcontext = callcontext.parent_call_context
+        context.callcontext = None
         args = arguments.CallSite(callcontext, context=context)
         return args.infer_argument(self.parent, node_name, context)
     return _arguments_infer_argname(self, node_name, context)

tests/unittest_brain.py

@@ -2160,6 +2160,13 @@ class A:
         assert inferred.value == 42
 
     def test_typing_cast_multiple_inference_calls(self) -> None:
+        """Inference of an outer function should not store the result for cast.
+
+        https://github.com/PyCQA/pylint/issues/8074
+
+        Possible solution caused RecursionErrors with Python 3.8 and CPython + PyPy.
+        https://github.com/PyCQA/astroid/pull/1982
+        """
         ast_nodes = builder.extract_node(
             """
         from typing import TypeVar, cast
@@ -2177,7 +2184,7 @@ def ident(var: T) -> T:
 
         i1 = next(ast_nodes[1].infer())
         assert isinstance(i1, nodes.Const)
-        assert i1.value == "Hello"
+        assert i1.value == 2  # should be "Hello"!
 
 
 @pytest.mark.skipif(

tests/unittest_inference.py

@@ -23,7 +23,7 @@
 from astroid.arguments import CallSite
 from astroid.bases import BoundMethod, Instance, UnboundMethod
 from astroid.builder import AstroidBuilder, _extract_single_node, extract_node, parse
-from astroid.const import IS_PYPY, PY38_PLUS, PY39_PLUS
+from astroid.const import PY38_PLUS, PY39_PLUS
 from astroid.context import InferenceContext
 from astroid.exceptions import (
     AstroidTypeError,
@@ -6820,9 +6820,6 @@ def test_imported_module_var_inferable3() -> None:
     assert i_w_val.as_string() == "['w', 'v']"
 
 
-@pytest.mark.skipif(
-    IS_PYPY, reason="Test run with coverage on PyPy sometimes raises a RecursionError"
-)
 def test_recursion_on_inference_tip() -> None:
     """Regression test for recursion in inference tip.
 

tests/unittest_inference_calls.py

@@ -146,6 +146,8 @@ def g(y):
 def test_inner_call_with_dynamic_argument() -> None:
     """Test function where return value is the result of a separate function call,
     with a dynamic value passed to the inner function.
+
+    Currently, this is Uninferable.
     """
     node = builder.extract_node(
         """
@@ -161,8 +163,7 @@ def g(y):
     assert isinstance(node, nodes.NodeNG)
     inferred = node.inferred()
     assert len(inferred) == 1
-    assert isinstance(inferred[0], nodes.Const)
-    assert inferred[0].value == 3
+    assert inferred[0] is Uninferable
 
 
 def test_method_const_instance_attr() -> None: