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serhiy-storchakaserhiy-storchaka
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Keep the empty prefix registered for other namespace
register_namespace("", uri) still makes it the default namespace, unless the default_namespace option is used for other uri. Serializing such tree no longer produces two xmlns attributes (pythongh-118416).
1 parent 1351010 commit c250651

2 files changed

Lines changed: 22 additions & 2 deletions

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‎Lib/test/test_xml_etree.py‎

Lines changed: 18 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -947,6 +947,24 @@ def test_tostring_default_namespace_attributes_round_trip(self):
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[sorted(e.attrib.items()) for e in elem.iter()]
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)
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def test_tostring_default_namespace_registered_empty_prefix(self):
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# gh-118416: the empty prefix is registered for other namespace,
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# so it cannot be used for the default namespace
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nsmap = ET.register_namespace._namespace_map
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self.addCleanup(nsmap.pop, 'default', None)
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ET.register_namespace('', 'default')
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elem = ET.Element('{default}elem')
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self.assertEqual(
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ET.tostring(elem, encoding='unicode',
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default_namespace='otherdefault'),
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'<ns1:elem xmlns="otherdefault" xmlns:ns1="default" />'
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)
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# without the option the registered prefix is used
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self.assertEqual(
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ET.tostring(elem, encoding='unicode'),
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'<elem xmlns="default" />'
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)
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def test_tostring_no_xml_declaration(self):
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elem = ET.XML('<body><tag/></body>')
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self.assertEqual(

‎Lib/xml/etree/ElementTree.py‎

Lines changed: 4 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -827,14 +827,16 @@ def get_prefix(uri, isattr):
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if isattr:
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prefix = attr_prefixes.get(uri)
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if prefix is None:
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# the default namespace is of no use for an attribute name
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# the empty prefix is of no use for an attribute name
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prefix = prefixes.get(uri) or None
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else:
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prefix = prefixes.get(uri)
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if prefix is not None:
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return prefix
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prefix = _namespace_map.get(uri)
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if not prefix:
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if prefix is None or not prefix and (isattr or default_namespace):
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# the empty prefix is of no use for an attribute name,
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# and the default namespace is used for other uri
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prefix = "ns%d" % len(namespaces)
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if prefix != "xml":
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namespaces[prefix] = uri

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