Patches #1298449 and #1298499: Add some missing checks for error

returns in cStringIO.c.  Thanks to Andrew Bennetts.

This must be a backport candidate.

Lib/test/test_StringIO.py

@@ -44,6 +44,13 @@ class TestGenericStringIO(unittest.TestCase):
         f.seek(0)
         self.assertEqual(f.getvalue(), 'abc')
 
+    def test_writelines_error(self):
+        def errorGen():
+            yield 'a'
+            raise KeyboardInterrupt()
+        f = self.MODULE.StringIO()
+        self.assertRaises(KeyboardInterrupt, f.writelines, errorGen())
+
     def test_truncate(self):
         eq = self.assertEqual
         f = self.MODULE.StringIO()

Misc/ACKS

@@ -50,6 +50,7 @@ Reimer Behrends
 Thomas Bellman
 Juan M. Bello Rivas
 Alexander Belopolsky
+Andrew Bennetts
 Andy Bensky
 Michel Van den Bergh
 Eric Beser

Misc/NEWS

@@ -149,6 +149,9 @@ present).
 Extension Modules
 -----------------
 
+- Patches #1298449 and #1298499: Add some missing checks for error
+  returns in cStringIO.c.
+
 - Patch #1297028: fix segfault if call type on MultibyteCodec,
   MultibyteStreamReader, or MultibyteStreamWriter
 

Modules/cStringIO.c

@@ -241,7 +241,10 @@ IO_readlines(IOobject *self, PyObject *args) {
 		line = PyString_FromStringAndSize (output, n);
 		if (!line) 
                         goto err;
-		PyList_Append (result, line);
+		if (PyList_Append (result, line) == -1) {
+			Py_DECREF (line);
+			goto err;
+		}
 		Py_DECREF (line);
                 length += n;
                 if (hint > 0 && length >= hint)
@@ -440,13 +443,18 @@ O_writelines(Oobject *self, PyObject *args) {
 			Py_DECREF(it);
 			Py_DECREF(s);
 			return NULL;
-		}
+               }
-		Py_DECREF(s);
+               Py_DECREF(s);
-	}
+       }
-	Py_DECREF(it);
-	Py_RETURN_NONE;
-}
 
+       Py_DECREF(it);
+
+       /* See if PyIter_Next failed */
+       if (PyErr_Occurred())
+               return NULL;
+
+       Py_RETURN_NONE;
+}
 static struct PyMethodDef O_methods[] = {
   /* Common methods: */
   {"flush",     (PyCFunction)IO_flush,    METH_NOARGS,  IO_flush__doc__},