gh-159437: Remove redundant tuple untracking guards

Author: mfalco-oai

Include/internal/pycore_tuple.h

@@ -11,9 +11,9 @@ extern "C" {
 #include "pycore_object.h"        // _PyObject_GC_IS_TRACKED
 #include "pycore_structs.h"       // _PyStackRef
 
-/* Check whether an object is eligible for tuple untracking.
- * `op`: The live object to inspect.
- * Returns: True for an exact tracked tuple with no NULL or potentially tracked items.
+/* Check whether an exact tracked tuple is eligible for untracking.
+ * `op`: A live exact tuple currently tracked by the GC.
+ * Returns: True if the tuple has no NULL or potentially tracked items.
  */
 extern bool _PyTuple_CanUntrack(PyObject *op);
 extern void _PyTuple_MaybeUntrack(PyObject *);

Objects/tupleobject.c

@@ -140,8 +140,8 @@ _PyTuple_CanUntrack(PyObject *op)
     PyTupleObject *t;
     Py_ssize_t i, n;
 
-    if (!PyTuple_CheckExact(op) || !_PyObject_GC_IS_TRACKED(op))
-        return false;
+    assert(PyTuple_CheckExact(op));
+    assert(_PyObject_GC_IS_TRACKED(op));
     t = (PyTupleObject *) op;
     n = Py_SIZE(t);
     for (i = 0; i < n; i++) {
@@ -159,6 +159,9 @@ _PyTuple_CanUntrack(PyObject *op)
 void
 _PyTuple_MaybeUntrack(PyObject *op)
 {
+    if (!PyTuple_CheckExact(op) || !_PyObject_GC_IS_TRACKED(op)) {
+        return;
+    }
     if (_PyTuple_CanUntrack(op)) {
         _PyObject_GC_UNTRACK(op);
     }