#3660: Correct a reference leak in PyUnicode_AsEncodedString when

the encoder does not return a bytes object.

Now test_unicode passes without leaking.

Reviewer: Antoine Pitrou.

Misc/NEWS

@@ -12,10 +12,13 @@ What's New in Python 3.0 release candidate 1
 Core and Builtins
 -----------------
 
-- Issue 3774: Added a few more checks in PyTokenizer_FindEncoding to handle
+- Issue #3660: Corrected a reference leak in str.encode() when the encoder
+  does not return a bytes object.
+
+- Issue #3774: Added a few more checks in PyTokenizer_FindEncoding to handle
   error conditions.
 
-- Issue 3594: Fix Parser/tokenizer.c:fp_setreadl() to open the file being
+- Issue #3594: Fix Parser/tokenizer.c:fp_setreadl() to open the file being
   tokenized by either a file path or file pointer for the benefit of
   PyTokenizer_FindEncoding().
 

Objects/unicodeobject.c

@@ -1328,7 +1328,7 @@ PyObject *PyUnicode_AsEncodedString(PyObject *unicode,
 
     if (!PyUnicode_Check(unicode)) {
         PyErr_BadArgument();
-        goto onError;
+        return NULL;
     }
 
     if (encoding == NULL)
@@ -1351,27 +1351,33 @@ PyObject *PyUnicode_AsEncodedString(PyObject *unicode,
     /* Encode via the codec registry */
     v = PyCodec_Encode(unicode, encoding, errors);
     if (v == NULL)
-        goto onError;
+        return NULL;
+
+    /* The normal path */
+    if (PyBytes_Check(v))
+        return v;
+
+    /* If the codec returns a buffer, raise a warning and convert to bytes */
     if (PyByteArray_Check(v)) {
         char msg[100];
+        PyObject *b;
         PyOS_snprintf(msg, sizeof(msg),
                       "encoder %s returned buffer instead of bytes",
                       encoding);
         if (PyErr_WarnEx(PyExc_RuntimeWarning, msg, 1) < 0) {
-            v = NULL;
+            Py_DECREF(v);
-            goto onError;
+            return NULL;
         }
-        v = PyBytes_FromStringAndSize(PyByteArray_AS_STRING(v), Py_SIZE(v));
+
+        b = PyBytes_FromStringAndSize(PyByteArray_AS_STRING(v), Py_SIZE(v));
+        Py_DECREF(v);
+        return b;
     }
-    else if (!PyBytes_Check(v)) {
+
     PyErr_Format(PyExc_TypeError,
                  "encoder did not return a bytes object (type=%.400s)",
                  Py_TYPE(v)->tp_name);
-        v = NULL;
+    Py_DECREF(v);
-    }
-    return v;
-
- onError:
     return NULL;
 }