Add a bound to the inference tips cache (and fix regressions from #2158)

astroid/context.py

@@ -140,6 +140,18 @@ def restore_path(self) -> Iterator[None]:
         yield
         self.path = path
 
+    def is_empty(self) -> bool:
+        return (
+            not self.path
+            and not self.nodes_inferred
+            and not self.callcontext
+            and not self.boundnode
+            and not self.lookupname
+            and not self.callcontext
+            and not self.extra_context
+            and not self.constraints
+        )
+
     def __str__(self) -> str:
         state = (
             f"{field}={pprint.pformat(getattr(self, field), width=80 - len(field))}"

astroid/inference_tip.py

@@ -6,6 +6,7 @@
 
 from __future__ import annotations
 
+from collections import OrderedDict
 from collections.abc import Generator
 from typing import Any, TypeVar
 
@@ -18,9 +19,9 @@
     TransformFn,
 )
 
-_cache: dict[
+_cache: OrderedDict[
     tuple[InferFn[Any], NodeNG, InferenceContext | None], list[InferenceResult]
-] = {}
+] = OrderedDict()
 
 _CURRENTLY_INFERRING: set[tuple[InferFn[Any], NodeNG]] = set()
 
@@ -44,7 +45,11 @@ def inner(
         if partial_cache_key in _CURRENTLY_INFERRING:
             # If through recursion we end up trying to infer the same
             # func + node we raise here.
+            _CURRENTLY_INFERRING.remove(partial_cache_key)
             raise UseInferenceDefault
+        if context is not None and context.is_empty():
+            # Fresh, empty contexts will defeat the cache.
+            context = None
         try:
             yield from _cache[func, node, context]
             return
@@ -55,11 +60,23 @@ def inner(
             # with slightly different contexts while still passing the simple
             # test cases included with this commit.
             _CURRENTLY_INFERRING.add(partial_cache_key)
-            result = _cache[func, node, context] = list(func(node, context, **kwargs))
-            # Remove recursion guard.
-            _CURRENTLY_INFERRING.remove(partial_cache_key)
-
-        yield from result
+            try:
+                # May raise UseInferenceDefault
+                result = _cache[func, node, context] = list(
+                    func(node, context, **kwargs)
+                )
+            finally:
+                # Remove recursion guard.
+                try:
+                    _CURRENTLY_INFERRING.remove(partial_cache_key)
+                except KeyError:
+                    pass  # Recursion may beat us to the punch.
+
+                if len(_cache) > 64:
+                    _cache.popitem(last=False)
+
+        # https://github.com/pylint-dev/pylint/issues/8686
+        yield from result  # pylint: disable=used-before-assignment
 
     return inner
 

tests/test_inference.py

@@ -31,7 +31,7 @@
 from astroid.arguments import CallSite
 from astroid.bases import BoundMethod, Instance, UnboundMethod, UnionType
 from astroid.builder import AstroidBuilder, _extract_single_node, extract_node, parse
-from astroid.const import PY39_PLUS, PY310_PLUS
+from astroid.const import IS_PYPY, PY39_PLUS, PY310_PLUS
 from astroid.context import CallContext, InferenceContext
 from astroid.exceptions import (
     AstroidTypeError,
@@ -6976,6 +6976,9 @@ 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.