python · gpshead · Jan 23, 2023 · Feb 5, 2022 · Feb 5, 2022 · Feb 7, 2022
diff --git a/Doc/library/xml.etree.elementtree.rst b/Doc/library/xml.etree.elementtree.rst
@@ -1045,9 +1045,9 @@ Element Objects
    :meth:`~object.__getitem__`, :meth:`~object.__setitem__`,
    :meth:`~object.__len__`.
 
-   Caution: Elements with no subelements will test as ``False``.  This behavior
-   will change in future versions.  Use specific ``len(elem)`` or ``elem is
-   None`` test instead. ::
+   Caution: Elements with no subelements will test as ``False``.  Testing the
+   truth value of an Element is deprecated and will raise an exception in
+   Python 3.14.  Use specific ``len(elem)`` or ``elem is None`` test instead.::
 
      element = root.find('foo')
 
@@ -1057,6 +1057,9 @@ Element Objects
      if element is None:
          print("element not found")
 
+   .. versionchanged:: 3.12
+      Testing the truth value of an Element emits :exc:`DeprecationWarning`.
+
    Prior to Python 3.8, the serialisation order of the XML attributes of
    elements was artificially made predictable by sorting the attributes by
    their name. Based on the now guaranteed ordering of dicts, this arbitrary

diff --git a/Doc/whatsnew/3.12.rst b/Doc/whatsnew/3.12.rst
@@ -413,6 +413,11 @@ Deprecated
   is no current event loop set and it decides to create one.
   (Contributed by Serhiy Storchaka and Guido van Rossum in :gh:`100160`.)
 
+* The :mod:`xml.etree.ElementTree` module now emits :exc:`DeprecationWarning`
+  when testing the truth value of an :class:`xml.etree.ElementTree.Element`.
+  Before, the Python implementation emitted :exc:`FutureWarning`, and the C
+  implementation emitted nothing.
+
 
 Pending Removal in Python 3.13
 ------------------------------
@@ -475,6 +480,9 @@ Pending Removal in Python 3.14
 * ``__package__`` and ``__cached__`` will cease to be set or taken
   into consideration by the import system (:gh:`97879`).
 
+* Testing the truth value of an :class:`xml.etree.ElementTree.Element`
+  is deprecated and will raise an exception in Python 3.14.
+
 
 Pending Removal in Future Versions
 ----------------------------------

diff --git a/Lib/test/test_xml_etree.py b/Lib/test/test_xml_etree.py
@@ -3957,6 +3957,25 @@ def test_correct_import_pyET(self):
         self.assertIsInstance(pyET.Element.__init__, types.FunctionType)
         self.assertIsInstance(pyET.XMLParser.__init__, types.FunctionType)
 
+# --------------------------------------------------------------------
+
+class BoolTest(unittest.TestCase):
+    def test_warning(self):
+        e = ET.fromstring('<a style="new"></a>')
+        msg = (
+            r"Testing an element's truth value will raise an exception in "
+            r"future versions.  "
+            r"Use specific 'len\(elem\)' or 'elem is not None' test instead.")
+        with self.assertWarnsRegex(DeprecationWarning, msg):
+            result = bool(e)
+        # Emulate prior behavior for now
+        self.assertIs(result, False)
+
+        # Element with children
+        ET.SubElement(e, 'b')
+        with self.assertWarnsRegex(DeprecationWarning, msg):
+            new_result = bool(e)
+        self.assertIs(new_result, True)
 
 # --------------------------------------------------------------------
 
@@ -4223,6 +4242,7 @@ def test_main(module=None):
         XMLPullParserTest,
         BugsTest,
         KeywordArgsTest,
+        BoolTest,
         C14NTest,
         ]
 

diff --git a/Lib/xml/etree/ElementTree.py b/Lib/xml/etree/ElementTree.py
@@ -200,9 +200,10 @@ def __len__(self):
 
     def __bool__(self):
         warnings.warn(
-            "The behav
E864
ior of this method will change in future versions.  "
+            "Testing an element's truth value will raise an exception in "
+            "future versions.  "
             "Use specific 'len(elem)' or 'elem is not None' test instead.",
-            FutureWarning, stacklevel=2
+            DeprecationWarning, stacklevel=2
             )
         return len(self._children) != 0 # emulate old behaviour, for now
 

diff --git a/Misc/NEWS.d/next/Library/2022-02-05-12-01-58.bpo-38941.8IhvyG.rst b/Misc/NEWS.d/next/Library/2022-02-05-12-01-58.bpo-38941.8IhvyG.rst
@@ -0,0 +1,4 @@
+The :mod:`xml.etree.ElementTree` module now emits :exc:`DeprecationWarning`
+when testing the truth value of an :class:`xml.etree.ElementTree.Element`.
+Before, the Python implementation emitted :exc:`FutureWarning`, and the C
+implementation emitted nothing.
diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
@@ -1449,6 +1449,23 @@ element_getitem(PyObject* self_, Py_ssize_t index)
     return Py_NewRef(self->extra->children[index]);
 }
 
+static int
+element_bool(PyObject* self_)
+{
+    ElementObject* self = (ElementObject*) self_;
+    if (PyErr_WarnEx(PyExc_DeprecationWarning,
+                     "Testing an element's truth value will raise an exception "
+                     "in future versions.  Use specific 'len(elem)' or "
+                     "'elem is not None' test instead.",
+                     1) < 0) {
+        return -1;
+    };
+    if (self->extra ? self->extra->length : 0) {
+        return 1;
+    }
+    return 0;
+}
+
 /*[clinic input]
 _elementtree.Element.insert
 
@@ -4156,6 +4173,7 @@ static PyType_Slot element_slots[] = {
     {Py_sq_length, element_length},
     {Py_sq_item, element_getitem},
     {Py_sq_ass_item, element_setitem},
+    {Py_nb_bool, element_bool},
     {Py_mp_length, element_length},
     {Py_mp_subscript, element_subscr},
     {Py_mp_ass_subscript, element_ass_subscr},