If a code object is compiled with nested scopes, define the CO_NESTED flag.

Add PyEval_GetNestedScopes() which returns a non-zero value if the
code for the current interpreter frame has CO_NESTED defined.

Include/ceval.h

@@ -28,6 +28,7 @@ DL_IMPORT(PyObject *) PyEval_GetLocals(void);
 DL_IMPORT(PyObject *) PyEval_GetOwner(void);
 DL_IMPORT(PyObject *) PyEval_GetFrame(void);
 DL_IMPORT(int) PyEval_GetRestricted(void);
+DL_IMPORT(int) PyEval_GetNestedScopes(void);
 
 DL_IMPORT(int) Py_FlushLine(void);
 

Include/compile.h

@@ -32,6 +32,7 @@ typedef struct {
 #define CO_NEWLOCALS	0x0002
 #define CO_VARARGS	0x0004
 #define CO_VARKEYWORDS	0x0008
+#define CO_NESTED       0x0010
 
 extern DL_IMPORT(PyTypeObject) PyCode_Type;
 

Python/ceval.c

@@ -2666,6 +2666,14 @@ PyEval_GetRestricted(void)
 	return current_frame == NULL ? 0 : current_frame->f_restricted;
 }
 
+int
+PyEval_GetNestedScopes(void)
+{
+	PyFrameObject *current_frame = PyThreadState_Get()->frame;
+	return current_frame == NULL ? 0 : 
+	    current_frame->f_code->co_flags & CO_NESTED;
+}
+
 int
 Py_FlushLine(void)
 {
@@ -3448,7 +3456,7 @@ exec_statement(PyFrameObject *f, PyObject *prog, PyObject *globals,
 	else if (PyFile_Check(prog)) {
 		FILE *fp = PyFile_AsFile(prog);
 		char *name = PyString_AsString(PyFile_Name(prog));
-		v = PyRun_File(fp, name, Py_file_input, globals, locals);
+		v = PyRun_File(fp, name, Py_file_input, globals, locals); 
 	}
 	else {
 		char *str;

Python/compile.c

@@ -4276,6 +4276,8 @@ static int
 symtable_update_flags(struct compiling *c, PySymtableEntryObject *ste,
 		      struct symbol_info *si)
 {
+	if (c->c_future && c->c_future->ff_nested_scopes)
+		c->c_flags |= CO_NESTED;
 	if (ste->ste_type != TYPE_MODULE)
 		c->c_flags |= CO_NEWLOCALS;
 	if (ste->ste_type == TYPE_FUNCTION) {