# HG changeset patch
# User Dirkjan Ochtman <dirkjan@ochtman.nl>
# Date 1406187458 -7200
#      Thu Jul 24 09:37:38 2014 +0200
# Branch 2.7
# Node ID 1ea34a107d82e09996a5bdab4c7320b144b693cf
# Parent  5549075d6223ab1f25ab25d5ef56d13bfe2ea0a4
Issue #21591: Handle exec backwards compatibility in the AST builder

Instead of deferring until runtime. This makes sure we hit the right
conditions in dealing with unqualified exec statements.

diff --git a/Python/ast.c b/Python/ast.c
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -2679,6 +2679,18 @@
     expr1 = ast_for_expr(c, CHILD(n, 1));
     if (!expr1)
         return NULL;
+
+    if (expr1->kind == Tuple_kind && n_children < 4 &&
+        (asdl_seq_LEN(expr1->v.Tuple.elts) == 2 ||
+         asdl_seq_LEN(expr1->v.Tuple.elts) == 3)) {
+        /* Backwards compatibility: pass exec args as a tuple */
+        globals = (expr_ty) asdl_seq_GET(expr1->v.Tuple.elts, 1);
+        if (asdl_seq_LEN(expr1->v.Tuple.elts) == 3) {
+            locals = (expr_ty) asdl_seq_GET(expr1->v.Tuple.elts, 2);
+        }
+        expr1 = (expr_ty) asdl_seq_GET(expr1->v.Tuple.elts, 0);
+    }
+
     if (n_children >= 4) {
         globals = ast_for_expr(c, CHILD(n, 3));
         if (!globals)
diff --git a/Python/ceval.c b/Python/ceval.c
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -4673,18 +4673,9 @@
 exec_statement(PyFrameObject *f, PyObject *prog, PyObject *globals,
                PyObject *locals)
 {
-    int n;
     PyObject *v;
     int plain = 0;
 
-    if (PyTuple_Check(prog) && globals == Py_None && locals == Py_None &&
-        ((n = PyTuple_Size(prog)) == 2 || n == 3)) {
-        /* Backward compatibility hack */
-        globals = PyTuple_GetItem(prog, 1);
-        if (n == 3)
-            locals = PyTuple_GetItem(prog, 2);
-        prog = PyTuple_GetItem(prog, 0);
-    }
     if (globals == Py_None) {
         globals = PyEval_GetGlobals();
         if (locals == Py_None) {