[3.12] gh-105340: include hidden fast-locals in locals() (GH-105715) (#106470)

gh-105340: include hidden fast-locals in locals() (GH-105715)

* gh-105340: include hidden fast-locals in locals()
(cherry picked from commit 104d7b760f)

Co-authored-by: Carl Meyer <carl@oddbird.net>

Python/bltinmodule.c

@@ -907,7 +907,7 @@ builtin_eval_impl(PyObject *module, PyObject *source, PyObject *globals,
                   PyObject *locals)
 /*[clinic end generated code: output=0a0824aa70093116 input=11ee718a8640e527]*/
 {
-    PyObject *result, *source_copy;
+    PyObject *result = NULL, *source_copy;
     const char *str;
 
     if (locals != Py_None && !PyMapping_Check(locals)) {
@@ -923,19 +923,25 @@ builtin_eval_impl(PyObject *module, PyObject *source, PyObject *globals,
     if (globals == Py_None) {
         globals = PyEval_GetGlobals();
         if (locals == Py_None) {
-            locals = PyEval_GetLocals();
+            locals = _PyEval_GetFrameLocals();
             if (locals == NULL)
                 return NULL;
         }
+        else {
+            Py_INCREF(locals);
+        }
     }
     else if (locals == Py_None)
-        locals = globals;
+        locals = Py_NewRef(globals);
+    else {
+        Py_INCREF(locals);
+    }
 
     if (globals == NULL || locals == NULL) {
         PyErr_SetString(PyExc_TypeError,
             "eval must be given globals and locals "
             "when called without a frame");
-        return NULL;
+        goto error;
     }
 
     int r = PyDict_Contains(globals, &_Py_ID(__builtins__));
@@ -943,34 +949,38 @@ builtin_eval_impl(PyObject *module, PyObject *source, PyObject *globals,
         r = PyDict_SetItem(globals, &_Py_ID(__builtins__), PyEval_GetBuiltins());
     }
     if (r < 0) {
-        return NULL;
+        goto error;
     }
 
     if (PyCode_Check(source)) {
         if (PySys_Audit("exec", "O", source) < 0) {
-            return NULL;
+            goto error;
         }
 
         if (PyCode_GetNumFree((PyCodeObject *)source) > 0) {
             PyErr_SetString(PyExc_TypeError,
                 "code object passed to eval() may not contain free variables");
-            return NULL;
+            goto error;
         }
-        return PyEval_EvalCode(source, globals, locals);
+        result = PyEval_EvalCode(source, globals, locals);
+    }
+    else {
+        PyCompilerFlags cf = _PyCompilerFlags_INIT;
+        cf.cf_flags = PyCF_SOURCE_IS_UTF8;
+        str = _Py_SourceAsString(source, "eval", "string, bytes or code", &cf, &source_copy);
+        if (str == NULL)
+            goto error;
+
+        while (*str == ' ' || *str == '\t')
+            str++;
+
+        (void)PyEval_MergeCompilerFlags(&cf);
+        result = PyRun_StringFlags(str, Py_eval_input, globals, locals, &cf);
+        Py_XDECREF(source_copy);
     }
 
-    PyCompilerFlags cf = _PyCompilerFlags_INIT;
-    cf.cf_flags = PyCF_SOURCE_IS_UTF8;
-    str = _Py_SourceAsString(source, "eval", "string, bytes or code", &cf, &source_copy);
-    if (str == NULL)
-        return NULL;
-
-    while (*str == ' ' || *str == '\t')
-        str++;
-
-    (void)PyEval_MergeCompilerFlags(&cf);
-    result = PyRun_StringFlags(str, Py_eval_input, globals, locals, &cf);
-    Py_XDECREF(source_copy);
+  error:
+    Py_XDECREF(locals);
     return result;
 }
 
@@ -1005,36 +1015,43 @@ builtin_exec_impl(PyObject *module, PyObject *source, PyObject *globals,
     if (globals == Py_None) {
         globals = PyEval_GetGlobals();
         if (locals == Py_None) {
-            locals = PyEval_GetLocals();
+            locals = _PyEval_GetFrameLocals();
             if (locals == NULL)
                 return NULL;
         }
+        else {
+            Py_INCREF(locals);
+        }
         if (!globals || !locals) {
             PyErr_SetString(PyExc_SystemError,
                             "globals and locals cannot be NULL");
             return NULL;
         }
     }
-    else if (locals == Py_None)
-        locals = globals;
+    else if (locals == Py_None) {
+        locals = Py_NewRef(globals);
+    }
+    else {
+        Py_INCREF(locals);
+    }
 
     if (!PyDict_Check(globals)) {
         PyErr_Format(PyExc_TypeError, "exec() globals must be a dict, not %.100s",
                      Py_TYPE(globals)->tp_name);
-        return NULL;
+        goto error;
     }
     if (!PyMapping_Check(locals)) {
         PyErr_Format(PyExc_TypeError,
             "locals must be a mapping or None, not %.100s",
             Py_TYPE(locals)->tp_name);
-        return NULL;
+        goto error;
     }
     int r = PyDict_Contains(globals, &_Py_ID(__builtins__));
     if (r == 0) {
         r = PyDict_SetItem(globals, &_Py_ID(__builtins__), PyEval_GetBuiltins());
     }
     if (r < 0) {
-        return NULL;
+        goto error;
     }
 
     if (closure == Py_None) {
@@ -1047,7 +1064,7 @@ builtin_exec_impl(PyObject *module, PyObject *source, PyObject *globals,
             if (closure) {
                 PyErr_SetString(PyExc_TypeError,
                     "cannot use a closure with this code object");
-                return NULL;
+                goto error;
             }
         } else {
             int closure_is_ok =
@@ -1067,12 +1084,12 @@ builtin_exec_impl(PyObject *module, PyObject *source, PyObject *globals,
                 PyErr_Format(PyExc_TypeError,
                     "code object requires a closure of exactly length %zd",
                     num_free);
-                return NULL;
+                goto error;
             }
         }
 
         if (PySys_Audit("exec", "O", source) < 0) {
-            return NULL;
+            goto error;
         }
 
         if (!closure) {
@@ -1099,7 +1116,7 @@ builtin_exec_impl(PyObject *module, PyObject *source, PyObject *globals,
                                        "string, bytes or code", &cf,
                                        &source_copy);
         if (str == NULL)
-            return NULL;
+            goto error;
         if (PyEval_MergeCompilerFlags(&cf))
             v = PyRun_StringFlags(str, Py_file_input, globals,
                                   locals, &cf);
@@ -1108,9 +1125,14 @@ builtin_exec_impl(PyObject *module, PyObject *source, PyObject *globals,
         Py_XDECREF(source_copy);
     }
     if (v == NULL)
-        return NULL;
+        goto error;
+    Py_DECREF(locals);
     Py_DECREF(v);
     Py_RETURN_NONE;
+
+  error:
+    Py_XDECREF(locals);
+    return NULL;
 }
 
 
@@ -1720,10 +1742,7 @@ static PyObject *
 builtin_locals_impl(PyObject *module)
 /*[clinic end generated code: output=b46c94015ce11448 input=7874018d478d5c4b]*/
 {
-    PyObject *d;
-
-    d = PyEval_GetLocals();
-    return Py_XNewRef(d);
+    return _PyEval_GetFrameLocals();
 }
 
 
@@ -2443,7 +2462,7 @@ builtin_vars_impl(PyObject *module, PyObject *object)
     PyObject *d;
 
     if (object == NULL) {
-        d = Py_XNewRef(PyEval_GetLocals());
+        d = _PyEval_GetFrameLocals();
     }
     else {
         if (_PyObject_LookupAttr(object, &_Py_ID(__dict__), &d) == 0) {

Python/ceval.c

@@ -2312,6 +2312,19 @@ PyEval_GetLocals(void)
     return locals;
 }
 
+PyObject *
+_PyEval_GetFrameLocals(void)
+{
+    PyThreadState *tstate = _PyThreadState_GET();
+     _PyInterpreterFrame *current_frame = _PyThreadState_GetFrame(tstate);
+    if (current_frame == NULL) {
+        _PyErr_SetString(tstate, PyExc_SystemError, "frame does not exist");
+        return NULL;
+    }
+
+    return _PyFrame_GetLocals(current_frame, 1);
+}
+
 PyObject *
 PyEval_GetGlobals(void)
 {