#5762: fix handling of empty namespace in minidom, which would result in AttributeError on toxml().

Lib/test/test_minidom.py

@@ -1489,6 +1489,13 @@ class MinidomTest(unittest.TestCase):
         doc.appendChild(doc.createComment("foo--bar"))
         self.assertRaises(ValueError, doc.toxml)
 
+    def testEmptyXMLNSValue(self):
+        doc = parseString("<element xmlns=''>\n"
+                          "<foo/>\n</element>")
+        doc2 = parseString(doc.toxml())
+        self.confirm(doc2.namespaceURI == xml.dom.EMPTY_NAMESPACE)
+
+
 def test_main():
     run_unittest(MinidomTest)
 

Lib/xml/dom/minidom.py

@@ -301,9 +301,10 @@ def _in_document(node):
 
 def _write_data(writer, data):
     "Writes datachars to writer."
-    data = data.replace("&", "&amp;").replace("<", "&lt;")
-    data = data.replace("\"", "&quot;").replace(">", "&gt;")
-    writer.write(data)
+    if data:
+        data = data.replace("&", "&amp;").replace("<", "&lt;"). \
+                    replace("\"", "&quot;").replace(">", "&gt;")
+        writer.write(data)
 
 def _get_elements_by_tagName_helper(parent, name, rc):
     for node in parent.childNodes:

Misc/NEWS

@@ -24,6 +24,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #5762: Fix AttributeError raised by ``xml.dom.minidom`` when an empty
+  XML namespace attribute is encountered.
+
 - Issue #2830: Add the ``html.escape()`` function, which quotes all problematic
   characters by default.  Deprecate ``cgi.escape()``.