Address review comments

Author: markshannon

Include/internal/pycore_stackref.h

@@ -392,7 +392,7 @@ PyStackRef_FromPyObjectBorrow(PyObject *obj)
         do {                                                            \
             _PyStackRef _close_tmp = (REF);                             \
             assert(!PyStackRef_IsNull(_close_tmp));                     \
-            if (!PyStackRef_IsDeferred(_close_tmp)) {                   \
+            if (!PyStackRef_IsDeferredOrTaggedInt(_close_tmp)) {                   \
                 Py_DECREF(PyStackRef_AsPyObjectBorrow(_close_tmp));     \
             }                                                           \
         } while (0)
@@ -704,23 +704,20 @@ PyStackRef_TYPE(_PyStackRef stackref) {
 
 // StackRef type checks
 
-static inline bool
-PyStackRef_GenCheck(_PyStackRef stackref)
-{
-    if (PyStackRef_IsTaggedInt(stackref)) {
-        return false;
+#define STACKREF_CHECK_FUNC(T) \
+    static inline bool \
+    PyStackRef_ ## T ## Check(_PyStackRef stackref) { \
+        if (PyStackRef_IsTaggedInt(stackref)) { \
+            return false; \
+        } \
+        return Py ## T ## _Check(PyStackRef_AsPyObjectBorrow(stackref)); \
     }
-    return PyGen_Check(PyStackRef_AsPyObjectBorrow(stackref));
-}
 
-static inline bool
-PyStackRef_BoolCheck(_PyStackRef stackref)
-{
-    if (PyStackRef_IsTaggedInt(stackref)) {
-        return false;
-    }
-    return PyBool_Check(PyStackRef_AsPyObjectBorrow(stackref));
-}
+STACKREF_CHECK_FUNC(Gen)
+STACKREF_CHECK_FUNC(Bool)
+STACKREF_CHECK_FUNC(ExceptionInstance)
+STACKREF_CHECK_FUNC(Code)
+STACKREF_CHECK_FUNC(Function)
 
 static inline bool
 PyStackRef_LongCheck(_PyStackRef stackref)
@@ -731,33 +728,6 @@ PyStackRef_LongCheck(_PyStackRef stackref)
     return PyLong_Check(PyStackRef_AsPyObjectBorrow(stackref));
 }
 
-static inline bool
-PyStackRef_ExceptionInstanceCheck(_PyStackRef stackref)
-{
-    if (PyStackRef_IsTaggedInt(stackref)) {
-        return false;
-    }
-    return PyExceptionInstance_Check(PyStackRef_AsPyObjectBorrow(stackref));
-}
-
-static inline bool
-PyStackRef_CodeCheck(_PyStackRef stackref)
-{
-    if (PyStackRef_IsTaggedInt(stackref)) {
-        return false;
-    }
-    return PyCode_Check(PyStackRef_AsPyObjectBorrow(stackref));
-}
-
-static inline bool
-PyStackRef_FunctionCheck(_PyStackRef stackref)
-{
-    if (PyStackRef_IsTaggedInt(stackref)) {
-        return false;
-    }
-    return PyFunction_Check(PyStackRef_AsPyObjectBorrow(stackref));
-}
-
 static inline void
 _PyThreadState_PushCStackRef(PyThreadState *tstate, _PyCStackRef *ref)
 {

Lib/test/test_list.py

@@ -370,6 +370,7 @@ def test_list_overwrite_local(self):
            iterable doesn't prematurely free the iterable"""
 
         def foo(x):
+            self.assertEqual(sys.getrefcount(x), 1)
             r = 0
             for i in x:
                 r += i

Python/stackrefs.c

@@ -219,7 +219,7 @@ PyStackRef_IsNullOrInt(_PyStackRef ref)
 _PyStackRef
 PyStackRef_IncrementTaggedIntNoOverflow(_PyStackRef ref)
 {
-    assert(ref.index != (uintptr_t)-1); // Overflow
+    assert(ref.index <= INT_MAX - 2); // No overflow
     return (_PyStackRef){ .index = ref.index + 2 };
 }