Patch 1463026: Support default namespace in XMLGenerator.

Fixes #847665. Will backport.

1 files changed, 19 insertions, 16 deletions

diff --git a/Lib/xml/sax/saxutils.py b/Lib/xml/sax/saxutils.py
index a496519..46818f3 100644
--- a/Lib/xml/sax/saxutils.py
+++ b/Lib/xml/sax/saxutils.py
@@ -100,6 +100,17 @@ class XMLGenerator(handler.ContentHandler):
         else:
             self._out.write(text.encode(self._encoding, _error_handling))
 
+    def _qname(self, name):
+        """Builds a qualified name from a (ns_url, localname) pair"""
+        if name[0]:
+            # The name is in a non-empty namespace
+            prefix = self._current_context[name[0]]
+            if prefix:
+                # If it is not the default namespace, prepend the prefix
+                return prefix + ":" + name[1]
+        # Return the unqualified name
+        return name[1]
+
     # ContentHandler methods
 
     def startDocument(self):
@@ -125,29 +136,21 @@ class XMLGenerator(handler.ContentHandler):
         self._write('</%s>' % name)
 
     def startElementNS(self, name, qname, attrs):
-        if name[0] is None:
-            # if the name was not namespace-scoped, use the unqualified part
-            name = name[1]
-        else:
-            # else try to restore the original prefix from the namespace
-            name = self._current_context[name[0]] + ":" + name[1]
-        self._write('<' + name)
+        self._write('<' + self._qname(name))
 
-        for pair in self._undeclared_ns_maps:
-            self._write(' xmlns:%s="%s"' % pair)
+        for prefix, uri in self._undeclared_ns_maps:
+            if prefix:
+                self._out.write(' xmlns:%s="%s"' % (prefix, uri))
+            else:
+                self._out.write(' xmlns="%s"' % uri)
         self._undeclared_ns_maps = []
 
         for (name, value) in attrs.items():
-            name = self._current_context[name[0]] + ":" + name[1]
-            self._write(' %s=%s' % (name, quoteattr(value)))
+            self._write(' %s=%s' % (self._qname(name), quoteattr(value)))
         self._write('>')
 
     def endElementNS(self, name, qname):
-        if name[0] is None:
-            name = name[1]
-        else:
-            name = self._current_context[name[0]] + ":" + name[1]
-        self._write('</%s>' % name)
+        self._write('</%s>' % self._qname(name))
 
     def characters(self, content):
         self._write(escape(content))