Speed up frame local item collection

Author: omkar-334

Misc/NEWS.d/next/Core_and_Builtins/2026-06-06-08-20-00.gh-issue-150942.Jk9pQr.rst

@@ -0,0 +1,3 @@
+Speed up frame local variable item collection by appending result pairs to the
+output list without an extra reference-count round-trip (using the internal
+reference-stealing list append helper).

Objects/frameobject.c

@@ -9,6 +9,7 @@
 #include "pycore_function.h"      // _PyFunction_FromConstructor()
 #include "pycore_genobject.h"     // _PyGen_GetGeneratorFromFrame()
 #include "pycore_interpframe.h"   // _PyFrame_GetLocalsArray()
+#include "pycore_list.h"          // _PyList_AppendTakeRef()
 #include "pycore_modsupport.h"    // _PyArg_CheckPositional()
 #include "pycore_object.h"        // _PyObject_GC_UNTRACK()
 #include "pycore_opcode_metadata.h" // _PyOpcode_Caches
@@ -636,9 +637,7 @@ framelocalsproxy_items(PyObject *self, PyObject *Py_UNUSED(ignored))
                 goto error;
             }
 
-            int rc = PyList_Append(items, pair);
-            Py_DECREF(pair);
-            if (rc < 0) {
+            if (_PyList_AppendTakeRef((PyListObject *)items, pair) < 0) {
                 goto error;
             }
         }
@@ -655,9 +654,7 @@ framelocalsproxy_items(PyObject *self, PyObject *Py_UNUSED(ignored))
                 goto error;
             }
 
-            int rc = PyList_Append(items, pair);
-            Py_DECREF(pair);
-            if (rc < 0) {
+            if (_PyList_AppendTakeRef((PyListObject *)items, pair) < 0) {
                 goto error;
             }
         }