[Python-checkins] cpython (2.7): Issue #21591: Handle exec backwards compatibility in the AST builder.

[dirkjan.ochtman]

http://hg.python.org/cpython/rev/33fb5600e9a1
changeset:   91923:33fb5600e9a1
branch:      2.7
parent:      91905:039ac3f01c4e
user:        Dirkjan Ochtman <dirkjan at ochtman.nl>
date:        Tue Jul 29 17:21:39 2014 +0200
summary:
  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.

Reviewed by Victor Stinner. Test follows in a later commit.

files:
  Misc/NEWS      |   3 +++
  Python/ast.c   |  12 ++++++++++++
  Python/ceval.c |   9 ---------
  3 files changed, 15 insertions(+), 9 deletions(-)


diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,9 @@
 Core and Builtins
 -----------------
 
+- Issue #21591: Correctly handle qualified exec statements in tuple form by
+  moving compatibility layer from run-time to AST transformation.
+
 Library
 -------
 
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) {

-- 
Repository URL: http://hg.python.org/cpython