gh-74929: Implement PEP 667 (GH-115153)

Python/ceval.c

@@ -2475,12 +2475,7 @@ PyEval_GetLocals(void)
         return NULL;
     }
 
-    if (_PyFrame_FastToLocalsWithError(current_frame) < 0) {
-        return NULL;
-    }
-
-    PyObject *locals = current_frame->f_locals;
-    assert(locals != NULL);
+    PyObject *locals = _PyEval_GetFrameLocals();
     return locals;
 }
 
@@ -2494,7 +2489,24 @@ _PyEval_GetFrameLocals(void)
         return NULL;
     }
 
-    return _PyFrame_GetLocals(current_frame, 1);
+    PyObject *locals = _PyFrame_GetLocals(current_frame);
+    if (locals == NULL) {
+        return NULL;
+    }
+
+    if (PyFrameLocalsProxy_Check(locals)) {
+        PyObject* ret = PyDict_New();
+        if (PyDict_Update(ret, locals)) {
+            Py_DECREF(ret);
+            return NULL;
+        }
+        Py_DECREF(locals);
+        return ret;
+    } else if (PyMapping_Check(locals)) {
+        return locals;
+    }
+
+    return NULL;
 }
 
 PyObject *
@@ -2508,6 +2520,28 @@ PyEval_GetGlobals(void)
     return current_frame->f_globals;
 }
 
+PyObject*
+PyEval_GetFrameLocals(void)
+{
+    return _PyEval_GetFrameLocals();
+}
+
+PyObject* PyEval_GetFrameGlobals(void)
+{
+    PyThreadState *tstate = _PyThreadState_GET();
+    _PyInterpreterFrame *current_frame = _PyThreadState_GetFrame(tstate);
+    if (current_frame == NULL) {
+        return NULL;
+    }
+    return Py_XNewRef(current_frame->f_globals);
+}
+
+PyObject* PyEval_GetFrameBuiltins(void)
+{
+    PyThreadState *tstate = _PyThreadState_GET();
+    return Py_XNewRef(_PyEval_GetBuiltins(tstate));
+}
+
 int
 PyEval_MergeCompilerFlags(PyCompilerFlags *cf)
 {

Python/intrinsics.c

@@ -123,18 +123,15 @@ static PyObject *
 import_star(PyThreadState* tstate, PyObject *from)
 {
     _PyInterpreterFrame *frame = tstate->current_frame;
-    if (_PyFrame_FastToLocalsWithError(frame) < 0) {
-        return NULL;
-    }
 
-    PyObject *locals = frame->f_locals;
+    PyObject *locals = _PyFrame_GetLocals(frame);
     if (locals == NULL) {
         _PyErr_SetString(tstate, PyExc_SystemError,
                             "no locals found during 'import *'");
         return NULL;
     }
     int err = import_all_from(tstate, locals, from);
-    _PyFrame_LocalsToFast(frame, 0);
+    Py_DECREF(locals);
     if (err < 0) {
         return NULL;
     }

Python/sysmodule.c

@@ -1022,13 +1022,6 @@ static PyObject *
 call_trampoline(PyThreadState *tstate, PyObject* callback,
                 PyFrameObject *frame, int what, PyObject *arg)
 {
-    /* Discard any previous modifications the frame's fast locals */
-    if (frame->f_fast_as_locals) {
-        if (PyFrame_FastToLocalsWithError(frame) < 0) {
-            return NULL;
-        }
-    }
-
     /* call the Python-level function */
     if (arg == NULL) {
         arg = Py_None;
@@ -1036,7 +1029,6 @@ call_trampoline(PyThreadState *tstate, PyObject* callback,
     PyObject *args[3] = {(PyObject *)frame, whatstrings[what], arg};
     PyObject *result = _PyObject_VectorcallTstate(tstate, callback, args, 3, NULL);
 
-    PyFrame_LocalsToFast(frame, 1);
     return result;
 }