The change in 2.7 branch breaks some software, including a test of Django (produce_xml_fragment from https://github.com/django/django/blob/1.4.5/tests/regressiontests/test_utils/tests.py).
The problem seems to not occur with Python 3.2, 3.3 and 3.4.

Before 010b455de0e0:
>>> from StringIO import StringIO
>>> from xml.sax.saxutils import XMLGenerator
>>> stream = StringIO()
>>> xml = XMLGenerator(stream, encoding='utf-8')
>>> xml.startElement("foo", {"aaa": "1.0", "bbb": "2.0"})
>>> xml.characters("Hello")
>>> xml.endElement("foo")
>>> xml.startElement("bar", {"ccc": "3.0", "ddd": "4.0"})
>>> xml.endElement("bar")
>>> stream.getvalue()
'<foo aaa="1.0" bbb="2.0">Hello</foo><bar ccc="3.0" ddd="4.0"></bar>'
>>>

After 010b455de0e0:
>>> from StringIO import StringIO
>>> from xml.sax.saxutils import XMLGenerator
>>> stream = StringIO()
>>> xml = XMLGenerator(stream, encoding='utf-8')
>>> xml.startElement("foo", {"aaa": "1.0", "bbb": "2.0"})
>>> xml.characters("Hello")
>>> xml.endElement("foo")
>>> xml.startElement("bar", {"ccc": "3.0", "ddd": "4.0"})
>>> xml.endElement("bar")
>>> stream.getvalue()
''
>>>