gh-131938: Update exception message for Element.remove() when an element is not found (#131972)

picnixz · web-flow · commit 04bc681e7cf5 · 2025-04-04T15:04:07.000Z
The exception message for `xml.etree.ElementTree.Element.remove` when an element is not found
has been updated from "list.remove(x): x not in list" to "Element.remove(x): element not found".
diff --git a/Lib/test/test_xml_etree.py b/Lib/test/test_xml_etree.py
@@ -344,9 +344,9 @@ def test_simpleops(self):
         self.serialize_check(element, '<tag key="value"><subtag /></tag>') # 4
         element.remove(subelement)
         self.serialize_check(element, '<tag key="value" />') # 5
-        with self.assertRaises(ValueError) as cm:
+        with self.assertRaisesRegex(ValueError,
+                                    r'Element\.remove\(.+\): element not found'):
             element.remove(subelement)
-        self.assertEqual(str(cm.exception), 'list.remove(x): x not in list')
         self.serialize_check(element, '<tag key="value" />') # 6
         element[0:0] = [subelement, subelement, subelement]
         self.serialize_check(element[1], '<subtag />')
diff --git a/Lib/xml/etree/ElementTree.py b/Lib/xml/etree/ElementTree.py
@@ -267,7 +267,11 @@ def remove(self, subelement):
 
         """
         # assert iselement(element)
-        self._children.remove(subelement)
+        try:
+            self._children.remove(subelement)
+        except ValueError:
+            # to align the error message with the C implementation
+            raise ValueError("Element.remove(x): element not found") from None
 
     def find(self, path, namespaces=None):
         """Find first matching element by tag name or path.
diff --git a/Misc/NEWS.d/next/Library/2025-04-01-13-44-26.gh-issue-131938.dm4Suq.rst b/Misc/NEWS.d/next/Library/2025-04-01-13-44-26.gh-issue-131938.dm4Suq.rst
@@ -0,0 +1,3 @@
+:mod:`xml.etree.ElementTree`: update the error message when an element to
+remove via :meth:`Element.remove <xml.etree.ElementTree.Element.remove>` is
+not found. Patch by Bénédikt Tran.
diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
@@ -1654,7 +1654,8 @@ _elementtree_Element_remove_impl(ElementObject *self, PyObject *subelement)
     }
 
     if (rc == 0) {
-        PyErr_SetString(PyExc_ValueError, "list.remove(x): x not in list");
+        PyErr_SetString(PyExc_ValueError,
+                        "Element.remove(x): element not found");
         return NULL;
     }
 

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	+:mod:`xml.etree.ElementTree`: update the error message when an element to
	`2`	+remove via :meth:`Element.remove <xml.etree.ElementTree.Element.remove>` is
	`3`	`+not found. Patch by Bénédikt Tran.`
Original file line number	Diff line number	Diff line change
`@@ -1654,7 +1654,8 @@ _elementtree_Element_remove_impl(ElementObject self, PyObject subelement)`
`1654`	`1654`	`}`
`1655`	`1655`
`1656`	`1656`	`if (rc == 0) {`
`1657`		`- PyErr_SetString(PyExc_ValueError, "list.remove(x): x not in list");`
	`1657`	`+ PyErr_SetString(PyExc_ValueError,`
	`1658`	`+ "Element.remove(x): element not found");`
`1658`	`1659`	`return NULL;`
`1659`	`1660`	`}`
`1660`	`1661`