gh-96844: Improve error message of list.remove (gh-106455)

Doc/library/doctest.rst

@@ -409,10 +409,10 @@ Simple example::
    >>> [1, 2, 3].remove(42)
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
-   ValueError: list.remove(x): x not in list
+   ValueError: 42 is not in list
 
-That doctest succeeds if :exc:`ValueError` is raised, with the ``list.remove(x):
+That doctest succeeds if :exc:`ValueError` is raised, with the ``42 is not in list``
-x not in list`` detail as shown.
+detail as shown.
 
 The expected output for an exception must start with a traceback header, which
 may be either of the following two lines, indented the same as the first line of

Lib/test/test_xml_etree.py

@@ -328,7 +328,7 @@ class ElementTreeTest(unittest.TestCase):
         self.serialize_check(element, '<tag key="value" />') # 5
         with self.assertRaises(ValueError) as cm:
             element.remove(subelement)
-        self.assertEqual(str(cm.exception), 'list.remove(x): x not in list')
+        self.assertIn('not in list', str(cm.exception))
         self.serialize_check(element, '<tag key="value" />') # 6
         element[0:0] = [subelement, subelement, subelement]
         self.serialize_check(element[1], '<subtag />')

Misc/NEWS.d/next/Core and Builtins/2023-07-06-00-35-44.gh-issue-96844.kwvoS-.rst

@@ -0,0 +1 @@
+Improve error message of :meth:`list.remove`. Patch by Dong-hee Na.

Objects/listobject.c

@@ -2694,7 +2694,7 @@ list_remove(PyListObject *self, PyObject *value)
         else if (cmp < 0)
             return NULL;
     }
-    PyErr_SetString(PyExc_ValueError, "list.remove(x): x not in list");
+    PyErr_Format(PyExc_ValueError, "%R is not in list", value);
     return NULL;
 }