gh-96175: add missing self._localName assignment in xml.dom.minidom.Attr (#96176)

X-Ref: https://github.com/python/typeshed/pull/8590#discussion_r951473977

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>

Lib/test/test_minidom.py

@@ -9,7 +9,7 @@ import unittest
 import pyexpat
 import xml.dom.minidom
 
-from xml.dom.minidom import parse, Node, Document, parseString
+from xml.dom.minidom import parse, Attr, Node, Document, parseString
 from xml.dom.minidom import getDOMImplementation
 from xml.parsers.expat import ExpatError
 
@@ -77,6 +77,20 @@ class MinidomTest(unittest.TestCase):
             dom.unlink()
             self.confirm(isinstance(dom, Document))
 
+    def testAttrModeSetsParamsAsAttrs(self):
+        attr = Attr("qName", "namespaceURI", "localName", "prefix")
+        self.assertEqual(attr.name, "qName")
+        self.assertEqual(attr.namespaceURI, "namespaceURI")
+        self.assertEqual(attr.prefix, "prefix")
+        self.assertEqual(attr.localName, "localName")
+
+    def testAttrModeSetsNonOptionalAttrs(self):
+        attr = Attr("qName", "namespaceURI", None, "prefix")
+        self.assertEqual(attr.name, "qName")
+        self.assertEqual(attr.namespaceURI, "namespaceURI")
+        self.assertEqual(attr.prefix, "prefix")
+        self.assertEqual(attr.localName, attr.name)
+
     def testGetElementsByTagName(self):
         dom = parse(tstfile)
         self.confirm(dom.getElementsByTagName("LI") == \

Lib/xml/dom/minidom.py

@@ -358,6 +358,8 @@ class Attr(Node):
         self._name = qName
         self.namespaceURI = namespaceURI
         self._prefix = prefix
+        if localName is not None:
+            self._localName = localName
         self.childNodes = NodeList()
 
         # Add the single child node that represents the value of the attr

Misc/NEWS.d/next/Library/2022-08-22-13-54-20.gh-issue-96175.bH7zGU.rst

@@ -0,0 +1 @@
+Fix unused ``localName`` parameter in the ``Attr`` class in :mod:`xml.dom.minidom`.