[Python-checkins] cpython (2.7): check by equality for __future__ not identity (closes #14378)

[benjamin.peterson]

http://hg.python.org/cpython/rev/1729ec440bb6
changeset:   75872:1729ec440bb6
branch:      2.7
parent:      75838:44a8385a8241
user:        Benjamin Peterson <benjamin at python.org>
date:        Thu Mar 22 08:19:04 2012 -0400
summary:
  check by equality for __future__ not identity (closes #14378)

files:
  Lib/test/test_ast.py |   6 ++++++
  Misc/NEWS            |   3 +++
  Python/future.c      |  11 +++--------
  3 files changed, 12 insertions(+), 8 deletions(-)


diff --git a/Lib/test/test_ast.py b/Lib/test/test_ast.py
--- a/Lib/test/test_ast.py
+++ b/Lib/test/test_ast.py
@@ -231,6 +231,12 @@
         im = ast.parse("from . import y").body[0]
         self.assertIsNone(im.module)
 
+    def test_non_interned_future_from_ast(self):
+        mod = ast.parse("from __future__ import division")
+        self.assertIsInstance(mod.body[0], ast.ImportFrom)
+        mod.body[0].module = " __future__ ".strip()
+        compile(mod, "<test>", "exec")
+
     def test_base_classes(self):
         self.assertTrue(issubclass(ast.For, ast.stmt))
         self.assertTrue(issubclass(ast.Name, ast.expr))
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -9,6 +9,9 @@
 Core and Builtins
 -----------------
 
+- Issue #14378: Fix compiling ast.ImportFrom nodes with a "__future__" string as
+  the module name that was not interned.
+
 - Issue #14331: Use significantly less stack space when importing modules by
   allocating path buffers on the heap instead of the stack.
 
diff --git a/Python/future.c b/Python/future.c
--- a/Python/future.c
+++ b/Python/future.c
@@ -59,13 +59,6 @@
 {
     int i, found_docstring = 0, done = 0, prev_line = 0;
 
-    static PyObject *future;
-    if (!future) {
-        future = PyString_InternFromString("__future__");
-        if (!future)
-            return 0;
-    }
-
     if (!(mod->kind == Module_kind || mod->kind == Interactive_kind))
         return 1;
 
@@ -92,7 +85,9 @@
         */
 
         if (s->kind == ImportFrom_kind) {
-            if (s->v.ImportFrom.module == future) {
+            PyObject *modname = s->v.ImportFrom.module;
+            if (PyString_GET_SIZE(modname) == 10 &&
+                !strcmp(PyString_AS_STRING(modname), "__future__")) {
                 if (done) {
                     PyErr_SetString(PyExc_SyntaxError,
                                     ERR_LATE_FUTURE);

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