Index: Lib/test/test_string.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/test/test_string.py,v
retrieving revision 1.25
diff -c -r1.25 test_string.py
*** Lib/test/test_string.py	1 May 2003 17:45:50 -0000	1.25
--- Lib/test/test_string.py	11 Aug 2004 22:37:56 -0000
***************
*** 52,57 ****
--- 52,80 ----
          self.checkraises(TypeError, string_tests.BadSeq1(), 'join', ' ')
          self.checkequal('a b c', string_tests.BadSeq2(), 'join', ' ')
  
+     def test_bug1001011(self):
+         # Make sure join returns a NEW object for single item sequences
+         # involving a subclass
+         # Make sure that it is of the appropriate type
+         # Check the optimisation still occurs for standard objects
+         class str_subclass(str): pass
+         s1 = str_subclass('abcd')
+         s2 = ''.join([s1])
+         self.failIf(s1 is s2)
+         self.assertEqual(type(s2), type(''))
+         s3 = 'abcd'
+         s4 = ''.join([s3])
+         self.failUnless(s3 is s4)
+         if test_support.have_unicode:
+             class unicode_subclass(unicode): pass
+             u1 = unicode_subclass(u'abcd')
+             u2 = ''.join([u1])
+             self.failIf(u1 is u2)
+             self.assertEqual(type(u2), type(u''))
+             u3 = u'abcd'
+             u4 = ''.join([u3])
+             self.failUnless(u3 is u4)
+ 
  class ModuleTest(unittest.TestCase):
  
      def test_attrs(self):
Index: Objects/stringobject.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Objects/stringobject.c,v
retrieving revision 2.224
diff -c -r2.224 stringobject.c
*** Objects/stringobject.c	7 Aug 2004 20:58:32 -0000	2.224
--- Objects/stringobject.c	11 Aug 2004 22:32:24 -0000
***************
*** 1618,1639 ****
  	}
  	if (seqlen == 1) {
  		item = PySequence_Fast_GET_ITEM(seq, 0);
! 		if (!PyString_Check(item) && !PyUnicode_Check(item)) {
! 			PyErr_Format(PyExc_TypeError,
! 				     "sequence item 0: expected string,"
! 				     " %.80s found",
! 				     item->ob_type->tp_name);
  			Py_DECREF(seq);
! 			return NULL;
  		}
- 		Py_INCREF(item);
- 		Py_DECREF(seq);
- 		return item;
  	}
  
! 	/* There are at least two things to join.  Do a pre-pass to figure out
! 	 * the total amount of space we'll need (sz), see whether any argument
! 	 * is absurd, and defer to the Unicode join if appropriate.
  	 */
  	for (i = 0; i < seqlen; i++) {
  		const size_t old_sz = sz;
--- 1618,1635 ----
  	}
  	if (seqlen == 1) {
  		item = PySequence_Fast_GET_ITEM(seq, 0);
! 		if (PyString_CheckExact(item) || PyUnicode_CheckExact(item)) {
! 			Py_INCREF(item);
  			Py_DECREF(seq);
! 			return item;
  		}
  	}
  
! 	/* There are at least two things to join, or else we have a subclass
! 	 * of the builtin types in the sequence.  
! 	 * Do a pre-pass to figure out the total amount of space we'll
! 	 * need (sz), see whether any argument is absurd, and defer to
! 	 * the Unicode join if appropriate.
  	 */
  	for (i = 0; i < seqlen; i++) {
  		const size_t old_sz = sz;