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.

diff --git a/Misc/NEWS b/Misc/NEWS
index bdd414ebeb93fb3acef4080b87ae70a2220927b8..f6dda992784e614069153999fddf27889c43b149 100644 (file)
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,9 @@ What's New in Python 2.7.9?
 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
index 80e6354ed4a2def26bca37ecfbec20006a5c46a1..ffd5679e09bc09fdafd875e8d4eb8db962b10391 100644 (file)
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -2679,6 +2679,18 @@ ast_for_exec_stmt(struct compiling *c, const node *n)
     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
index e00860831f15f3d4425db0f42b167628480da45b..38f51faf69c38777705e7228ab36f718993aa926 100644 (file)
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -4673,18 +4673,9 @@ static int
 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) {