Issue #22077: Improve index error messages for bytearrays, bytes, lists, and

tuples by adding 'or slices'. Added ', not <typename' for bytearrays.
Original patch by Claudiu Popa.

Lib/test/list_tests.py

@@ -30,6 +30,12 @@ class CommonTest(seq_tests.CommonTest):
         self.assertNotEqual(id(a), id(b))
         self.assertEqual(a, b)
 
+    def test_getitem_error(self):
+        msg = "list indices must be integers or slices"
+        with self.assertRaisesRegex(TypeError, msg):
+            a = []
+            a['a'] = "python"
+
     def test_repr(self):
         l0 = []
         l2 = [0, 1, 2]
@@ -120,6 +126,10 @@ class CommonTest(seq_tests.CommonTest):
         a[-1] = 9
         self.assertEqual(a, self.type2test([5,6,7,8,9]))
 
+        msg = "list indices must be integers or slices"
+        with self.assertRaisesRegex(TypeError, msg):
+            a['a'] = "python"
+
     def test_delitem(self):
         a = self.type2test([0, 1])
         del a[1]

Lib/test/test_bytes.py

@@ -699,6 +699,11 @@ class BaseBytesTest:
 class BytesTest(BaseBytesTest, unittest.TestCase):
     type2test = bytes
 
+    def test_getitem_error(self):
+        msg = "byte indices must be integers or slices"
+        with self.assertRaisesRegex(TypeError, msg):
+            b'python'['a']
+
     def test_buffer_is_readonly(self):
         fd = os.open(__file__, os.O_RDONLY)
         with open(fd, "rb", buffering=0) as f:
@@ -753,6 +758,17 @@ class BytesTest(BaseBytesTest, unittest.TestCase):
 class ByteArrayTest(BaseBytesTest, unittest.TestCase):
     type2test = bytearray
 
+    def test_getitem_error(self):
+        msg = "bytearray indices must be integers or slices"
+        with self.assertRaisesRegex(TypeError, msg):
+            bytearray(b'python')['a']
+
+    def test_setitem_error(self):
+        msg = "bytearray indices must be integers or slices"
+        with self.assertRaisesRegex(TypeError, msg):
+            b = bytearray(b'python')
+            b['a'] = "python"
+
     def test_nohash(self):
         self.assertRaises(TypeError, hash, bytearray())
 

Lib/test/test_tuple.py

@@ -6,6 +6,11 @@ import pickle
 class TupleTest(seq_tests.CommonTest):
     type2test = tuple
 
+    def test_getitem_error(self):
+        msg = "tuple indices must be integers or slices"
+        with self.assertRaisesRegex(TypeError, msg):
+            ()['a']
+
     def test_constructors(self):
         super().test_constructors()
         # calling built-in types without argument must return empty

Misc/NEWS

@@ -10,6 +10,10 @@ Release date: TBA
 Core and Builtins
 -----------------
 
+- Issue #22077: Improve index error messages for bytearrays, bytes, lists,
+  and tuples by adding 'or slices'. Added ', not <typename' for bytearrays.
+  Original patch by Claudiu Popa.
+
 - Issue #18395: Rename ``_Py_char2wchar()`` to :c:func:`Py_DecodeLocale`,
   rename ``_Py_wchar2char()`` to :c:func:`Py_EncodeLocale`, and document
   these functions.

Objects/bytearrayobject.c

@@ -445,7 +445,9 @@ bytearray_subscript(PyByteArrayObject *self, PyObject *index)
         }
     }
     else {
-        PyErr_SetString(PyExc_TypeError, "bytearray indices must be integers");
+        PyErr_Format(PyExc_TypeError,
+                     "bytearray indices must be integers or slices, not %.200s",
+                     Py_TYPE(index)->tp_name);
         return NULL;
     }
 }
@@ -650,7 +652,9 @@ bytearray_ass_subscript(PyByteArrayObject *self, PyObject *index, PyObject *valu
         }
     }
     else {
-        PyErr_SetString(PyExc_TypeError, "bytearray indices must be integer");
+        PyErr_Format(PyExc_TypeError,
+                     "bytearray indices must be integers or slices, not %.200s",
+                      Py_TYPE(index)->tp_name);
         return -1;
     }
 

Objects/bytesobject.c

@@ -999,7 +999,7 @@ bytes_subscript(PyBytesObject* self, PyObject* item)
     }
     else {
         PyErr_Format(PyExc_TypeError,
-                     "byte indices must be integers, not %.200s",
+                     "byte indices must be integers or slices, not %.200s",
                      Py_TYPE(item)->tp_name);
         return NULL;
     }

Objects/listobject.c

@@ -2444,7 +2444,7 @@ list_subscript(PyListObject* self, PyObject* item)
     }
     else {
         PyErr_Format(PyExc_TypeError,
-                     "list indices must be integers, not %.200s",
+                     "list indices must be integers or slices, not %.200s",
                      item->ob_type->tp_name);
         return NULL;
     }
@@ -2608,7 +2608,7 @@ list_ass_subscript(PyListObject* self, PyObject* item, PyObject* value)
     }
     else {
         PyErr_Format(PyExc_TypeError,
-                     "list indices must be integers, not %.200s",
+                     "list indices must be integers or slices, not %.200s",
                      item->ob_type->tp_name);
         return -1;
     }

Objects/tupleobject.c

@@ -746,7 +746,7 @@ tuplesubscript(PyTupleObject* self, PyObject* item)
     }
     else {
         PyErr_Format(PyExc_TypeError,
-                     "tuple indices must be integers, not %.200s",
+                     "tuple indices must be integers or slices, not %.200s",
                      Py_TYPE(item)->tp_name);
         return NULL;
     }