[Python-checkins] r59171 - in python/branches/release25-maint: Lib/test/test_funcattrs.py Misc/NEWS Objects/cellobject.c

[amaury.forgeotdarc]

Author: amaury.forgeotdarc
Date: Sat Nov 24 14:53:29 2007
New Revision: 59171

Modified:
   python/branches/release25-maint/Lib/test/test_funcattrs.py
   python/branches/release25-maint/Misc/NEWS
   python/branches/release25-maint/Objects/cellobject.c
Log:
Issue #1445: Fix a SystemError when accessing the ``cell_contents``
attribute of an empty cell object.  Now a ValueError is raised.

Backport of r59170.


Modified: python/branches/release25-maint/Lib/test/test_funcattrs.py
==============================================================================
--- python/branches/release25-maint/Lib/test/test_funcattrs.py	(original)
+++ python/branches/release25-maint/Lib/test/test_funcattrs.py	Sat Nov 24 14:53:29 2007
@@ -242,6 +242,17 @@
     verify(c[0].__class__.__name__ == "cell") # don't have a type object handy
     cantset(f, "func_closure", c)
 
+def test_empty_cell():
+    def f(): print a
+    try:
+        f.func_closure[0].cell_contents
+    except ValueError:
+        pass
+    else:
+        raise TestFailed, "shouldn't be able to read an empty cell"
+
+    a = 12
+
 def test_func_doc():
     def f(): pass
     verify(f.__doc__ is None)
@@ -385,6 +396,7 @@
 
 def testmore():
     test_func_closure()
+    test_empty_cell()
     test_func_doc()
     test_func_globals()
     test_func_name()

Modified: python/branches/release25-maint/Misc/NEWS
==============================================================================
--- python/branches/release25-maint/Misc/NEWS	(original)
+++ python/branches/release25-maint/Misc/NEWS	Sat Nov 24 14:53:29 2007
@@ -1,4 +1,4 @@
-+++++++++++
++++++++++++
 Python News
 +++++++++++
 
@@ -12,6 +12,9 @@
 Core and builtins
 -----------------
 
+- Issue #1445: Fix a SystemError when accessing the ``cell_contents`` 
+  attribute of an empty cell object.
+
 - Issue #1265: Fix a problem with sys.settrace, if the tracing function uses a
   generator expression when at the same time the executed code is closing a
   paused generator.

Modified: python/branches/release25-maint/Objects/cellobject.c
==============================================================================
--- python/branches/release25-maint/Objects/cellobject.c	(original)
+++ python/branches/release25-maint/Objects/cellobject.c	Sat Nov 24 14:53:29 2007
@@ -89,7 +89,12 @@
 static PyObject *
 cell_get_contents(PyCellObject *op, void *closure)
 {
-	Py_XINCREF(op->ob_ref);
+	if (op->ob_ref == NULL)
+	{
+		PyErr_SetString(PyExc_ValueError, "Cell is empty");
+		return NULL;
+	}
+	Py_INCREF(op->ob_ref);
 	return op->ob_ref;
 }