Issue #5027: The standard `xml` namespace is now understood by
xml.sax.saxutils.XMLGenerator as being bound to
http://www.w3.org/XML/1998/namespace. Patch by Troy J. Farrell.
diff --git a/Lib/test/test_sax.py b/Lib/test/test_sax.py
index 143ddf2..c4b211f 100644
--- a/Lib/test/test_sax.py
+++ b/Lib/test/test_sax.py
@@ -11,6 +11,7 @@
from xml.sax.saxutils import XMLGenerator, escape, unescape, quoteattr, \
XMLFilterBase
from xml.sax.expatreader import create_parser
+from xml.sax.handler import feature_namespaces
from xml.sax.xmlreader import InputSource, AttributesImpl, AttributesNSImpl
from io import StringIO
from test.support import findfile, run_unittest
@@ -385,6 +386,60 @@
self.assertEquals(result.getvalue(),
start+'<my:a xmlns:my="qux" b="c"/>')
+ def test_5027_1(self):
+ # The xml prefix (as in xml:lang below) is reserved and bound by
+ # definition to http://www.w3.org/XML/1998/namespace. XMLGenerator had
+ # a bug whereby a KeyError is thrown because this namespace is missing
+ # from a dictionary.
+ #
+ # This test demonstrates the bug by parsing a document.
+ test_xml = StringIO(
+ '<?xml version="1.0"?>'
+ '<a:g1 xmlns:a="http://example.com/ns">'
+ '<a:g2 xml:lang="en">Hello</a:g2>'
+ '</a:g1>')
+
+ parser = make_parser()
+ parser.setFeature(feature_namespaces, True)
+ result = StringIO()
+ gen = XMLGenerator(result)
+ parser.setContentHandler(gen)
+ parser.parse(test_xml)
+
+ self.assertEquals(result.getvalue(),
+ start + (
+ '<a:g1 xmlns:a="http://example.com/ns">'
+ '<a:g2 xml:lang="en">Hello</a:g2>'
+ '</a:g1>'))
+
+ def test_5027_2(self):
+ # The xml prefix (as in xml:lang below) is reserved and bound by
+ # definition to http://www.w3.org/XML/1998/namespace. XMLGenerator had
+ # a bug whereby a KeyError is thrown because this namespace is missing
+ # from a dictionary.
+ #
+ # This test demonstrates the bug by direct manipulation of the
+ # XMLGenerator.
+ result = StringIO()
+ gen = XMLGenerator(result)
+
+ gen.startDocument()
+ gen.startPrefixMapping('a', 'http://example.com/ns')
+ gen.startElementNS(('http://example.com/ns', 'g1'), 'g1', {})
+ lang_attr = {('http://www.w3.org/XML/1998/namespace', 'lang'): 'en'}
+ gen.startElementNS(('http://example.com/ns', 'g2'), 'g2', lang_attr)
+ gen.characters('Hello')
+ gen.endElementNS(('http://example.com/ns', 'g2'), 'g2')
+ gen.endElementNS(('http://example.com/ns', 'g1'), 'g1')
+ gen.endPrefixMapping('a')
+ gen.endDocument()
+
+ self.assertEquals(result.getvalue(),
+ start + (
+ '<a:g1 xmlns:a="http://example.com/ns">'
+ '<a:g2 xml:lang="en">Hello</a:g2>'
+ '</a:g1>'))
+
class XMLFilterBaseTest(unittest.TestCase):
def test_filter_basic(self):
diff --git a/Lib/xml/sax/saxutils.py b/Lib/xml/sax/saxutils.py
index 46946fc..625bc12 100644
--- a/Lib/xml/sax/saxutils.py
+++ b/Lib/xml/sax/saxutils.py
@@ -100,6 +100,12 @@
def _qname(self, name):
"""Builds a qualified name from a (ns_url, localname) pair"""
if name[0]:
+ # Per http://www.w3.org/XML/1998/namespace, The 'xml' prefix is
+ # bound by definition to http://www.w3.org/XML/1998/namespace. It
+ # does not need to be declared and will not usually be found in
+ # self._current_context.
+ if 'http://www.w3.org/XML/1998/namespace' == name[0]:
+ return 'xml:' + name[1]
# The name is in a non-empty namespace
prefix = self._current_context[name[0]]
if prefix: