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

diff --git a/Doc/library/doctest.rst b/Doc/library/doctest.rst
index d6e4dca0860671318a2231b6d5e6493b5a9c8329..92da6133f9bf09e7c67499a68845ca5f7c47a6cb 100644 (file)
--- a/Doc/library/doctest.rst
+++ b/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):
-x not in list`` detail as shown.
+That doctest succeeds if :exc:`ValueError` is raised, with the ``42 is not in list``
+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

diff --git a/Lib/test/test_xml_etree.py b/Lib/test/test_xml_etree.py
index 11efee00582e014fc7321d2805ee0fb87d09a20b..b9352cb865d027ea3edfe09c858533c86c814296 100644 (file)
--- a/Lib/test/test_xml_etree.py
+++ b/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 />')

diff --git a/Misc/NEWS.d/next/Core and Builtins/2023-07-06-00-35-44.gh-issue-96844.kwvoS-.rst b/Misc/NEWS.d/next/Core and Builtins/2023-07-06-00-35-44.gh-issue-96844.kwvoS-.rst
new file mode 100644 (file)
index 0000000..5533417
--- /dev/null
+++ b/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.

diff --git a/Objects/listobject.c b/Objects/listobject.c
index 98fa08962b6aad3cfc537715488a715dacea0f71..144ede6351e03cf637a8c94a8021943d7eb8b005 100644 (file)
--- a/Objects/listobject.c
+++ b/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;
 }