python · NekoAsakura · Feb 16, 2026 · serhiy-storchaka · Feb 19, 2026 · serhiy-storchaka
diff --git a/Doc/library/xml.etree.elementtree.rst b/Doc/library/xml.etree.elementtree.rst
@@ -879,7 +879,7 @@ Element Objects
   :noindex:
   :no-index:

-.. class:: Element(tag, attrib={}, **extra)
+.. class:: Element(tag, /, attrib={}, **extra)

   Element class.  This class defines the Element interface, and provides a
   reference implementation of this interface.
@@ -889,6 +889,9 @@ Element Objects
   an optional dictionary, containing element attributes.  *extra* contains
   additional attributes, given as keyword arguments.

+   .. versionchanged:: 3.15
-   .. versionchanged:: 3.15
+   .. versionchanged:: next
-   .. versionchanged:: 3.15
+   .. versionchanged:: next
+      *tag* is now a positional-only parameter.
+

   .. attribute:: tag


diff --git a/Lib/test/test_xml_etree.py b/Lib/test/test_xml_etree.py
@@ -381,6 +381,22 @@ def test_simpleops(self):
        self.serialize_check(element,
                '<tag key="value"><subtag /><subtag /></tag>')

+    def test_positional_only_parameter(self):
+        # Test Element positional-only parameters (gh-144846).
+
+        # 'tag' is positional-only
+        with self.assertRaises(TypeError):
+            ET.Element(tag='fail')
+
+        # 'attrib' can be passed as keyword
+        e = ET.Element('e', attrib={'key': 'value'})
+        self.assertEqual(e.get('key'), 'value')
+
+        # 'tag' as kwarg becomes an XML attribute, not the element tag
+        e = ET.Element('e', tag='foo')
+        self.assertEqual(e.tag, 'e')
+        self.assertEqual(e.get('tag'), 'foo')
+
    def test_cdata(self):
        # Test CDATA handling (etc).


diff --git a/Lib/xml/etree/ElementTree.py b/Lib/xml/etree/ElementTree.py
@@ -164,7 +164,7 @@ class Element:

    """

-    def __init__(self, tag, attrib={}, **extra):
+    def __init__(self, tag, /, attrib={}, **extra):
        if not isinstance(attrib, dict):
            raise TypeError("attrib must be dict, not %s" % (
                attrib.__class__.__name__,))

diff --git a/Misc/NEWS.d/next/Library/2026-02-16-10-32-44.gh-issue-144846.4eda4bd2.rst b/Misc/NEWS.d/next/Library/2026-02-16-10-32-44.gh-issue-144846.4eda4bd2.rst
@@ -0,0 +1,2 @@
+Made the *tag* parameter of :class:`xml.etree.ElementTree.Element`
+positional-only, matching the behavior of the C accelerator.
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		Made the tag parameter of :class:`xml.etree.ElementTree.Element`
		positional-only, matching the behavior of the C accelerator.