gh-54873: Add support for namespaces prefixes to xml.sax.expatreader

Lib/test/test_xml_expatreader.py

@@ -0,0 +1,24 @@
+import unittest
+
+from xml.sax.expatreader import create_parser
+from xml.sax import handler
+
+
+class feature_namespace_prefixes(unittest.TestCase):
+    def setUp(self):
+        self.parser = create_parser()
+        self.parser.setFeature(handler.feature_namespaces, 1)
+        self.parser.setFeature(handler.feature_namespace_prefixes, 1)
+
+    def test_prefix_given(self):
+        class Handler(handler.ContentHandler):
+            def startElementNS(self, name, qname, attrs):
+                self.qname = qname
+
+        h = Handler()
+
+        self.parser.setContentHandler(h)
+        self.parser.feed("<Q:E xmlns:Q='http://example.org/testuri'/>")
+        self.parser.close()
+        print("self.assertEqual")
+        self.assertFalse(h.qname is None)

Lib/xml/sax/expatreader.py

@@ -91,6 +91,7 @@ def __init__(self, namespaceHandling=0, bufsize=2**16-20):
         self._entity_stack = []
         self._external_ges = 0
         self._interning = None
+        self._namespace_prefixes = 1
 
     # XMLReader methods
 
@@ -126,8 +127,9 @@ def getFeature(self, name):
             return self._namespaces
         elif name == feature_string_interning:
             return self._interning is not None
-        elif name in (feature_validation, feature_external_pes,
-                      feature_namespace_prefixes):
+        elif name == feature_namespace_prefixes:
+            return self._namespace_prefixes
+        elif name in (feature_validation, feature_external_pes):
             return 0
         elif name == feature_external_ges:
             return self._external_ges
@@ -147,6 +149,8 @@ def setFeature(self, name, state):
                     self._interning = {}
             else:
                 self._interning = None
+        elif name == feature_namespace_prefixes:
+            self._namespace_prefixes = state
         elif name == feature_validation:
             if state:
                 raise SAXNotSupportedException(
@@ -155,10 +159,6 @@ def setFeature(self, name, state):
             if state:
                 raise SAXNotSupportedException(
                     "expat does not read external parameter entities")
-        elif name == feature_namespace_prefixes:
-            if state:
-                raise SAXNotSupportedException(
-                    "expat does not report namespace prefixes")
         else:
             raise SAXNotRecognizedException(
                 "Feature '%s' not recognized" % name)
@@ -347,11 +347,14 @@ def start_element_ns(self, name, attrs):
         pair = name.split()
         if len(pair) == 1:
             # no namespace
+            elem_qname = name
             pair = (None, name)
         elif len(pair) == 3:
+            elem_qname = "%s:%s" % (pair[2], pair[1])
             pair = pair[0], pair[1]
         else:
             # default namespace
+            elem_qname = pair[1]
             pair = tuple(pair)
 
         newattrs = {}
@@ -374,7 +377,7 @@ def start_element_ns(self, name, attrs):
             newattrs[apair] = value
             qnames[apair] = qname
 
-        self._cont_handler.startElementNS(pair, None,
+        self._cont_handler.startElementNS(pair, elem_qname,
                                           AttributesNSImpl(newattrs, qnames))
 
     def end_element_ns(self, name):

Misc/NEWS.d/next/Library/2024-04-26-14-21-04.gh-issue-54873.vf2bfp.rst

@@ -0,0 +1,2 @@
+Backported namespaces prefixes support for xml.sax.expatreader from PyXml
+(0.8.4)