bpo-39495: Remove default value from C impl of TreeBuilder.start (GH-18275)

Author: hauntsaninja

Lib/test/test_xml_etree.py

@@ -2259,6 +2259,10 @@ def test_expat224_utf8_bug_file(self):
         text = text[6:-4]
         self.assertEqual(root.get('b'), text)
 
+    def test_39495_treebuilder_start(self):
+        self.assertRaises(TypeError, ET.TreeBuilder().start, "tag")
+        self.assertRaises(TypeError, ET.TreeBuilder().start, "tag", None)
+
 
 
 # --------------------------------------------------------------------

Misc/NEWS.d/next/Library/2020-01-30-07-02-02.bpo-39495.8LsIRN.rst

@@ -0,0 +1 @@
+Remove default value from *attrs* parameter of :meth:`xml.etree.ElementTree.TreeBuilder.start` for consistency between Python and C implementations.

Modules/_elementtree.c

@@ -3038,15 +3038,15 @@ _elementtree_TreeBuilder_close_impl(TreeBuilderObject *self)
 _elementtree.TreeBuilder.start
 
     tag: object
-    attrs: object = None
+    attrs: object(subclass_of='&PyDict_Type')
     /
 
 [clinic start generated code]*/
 
 static PyObject *
 _elementtree_TreeBuilder_start_impl(TreeBuilderObject *self, PyObject *tag,
                                     PyObject *attrs)
-/*[clinic end generated code: output=e7e9dc2861349411 input=95fc1758dd042c65]*/
+/*[clinic end generated code: output=e7e9dc2861349411 input=7288e9e38e63b2b6]*/
 {
     return treebuilder_handle_start(self, tag, attrs);
 }