Patch # 1145 by Thomas Lee:

str.join(...) now applies str() to the sequence elements if they're
not strings alraedy, except for bytes, which still raise TypeError
(for the same reasons why ""==b"" raises it).

1 files changed, 13 insertions, 7 deletions

diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index c40f0be..ad78492 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -5412,14 +5412,20 @@ PyUnicode_Join(PyObject *separator, PyObject *seq)
 
 	item = PySequence_Fast_GET_ITEM(fseq, i);
 	/* Convert item to Unicode. */
-	if (! PyUnicode_Check(item) && ! PyString_Check(item)) {
-	    PyErr_Format(PyExc_TypeError,
-			 "sequence item %zd: expected string or Unicode,"
-			 " %.80s found",
-			 i, Py_Type(item)->tp_name);
-	    goto onError;
+	if (!PyString_Check(item) && !PyUnicode_Check(item))
+	{
+		if (PyBytes_Check(item))
+		{
+			PyErr_Format(PyExc_TypeError,
+                            "sequence item %d: join() will not operate on "
+                            "bytes objects", i);
+			goto onError;
+		}
+		item = PyObject_Unicode(item);
 	}
-	item = PyUnicode_FromObject(item);
+	else
+		item = PyUnicode_FromObject(item);
+
 	if (item == NULL)
 	    goto onError;
 	/* We own a reference to item from here on. */