gh-142083: Document the 'w' type code in the array.array docstring

The type code table in the array.array docstring did not list the 'w'
type code, although array.typecodes has included it since 3.13.  The
other points raised in the issue concerned the 'u' type code, which no
longer exists: it was removed, together with its note about narrow and
wide builds, in gh-80480.  What remains is the request to say that 'w'
holds Py_UCS4, so the new row names that C type, which is also what the
"C Type" column of the table in Doc/library/array.rst gives for 'w'.

Add a test asserting that the table lists exactly the supported type
codes and that the minimum size it gives for each of them is one the
implementation really meets.

Author: v0ropaev

Lib/test/test_array.py

@@ -12,6 +12,7 @@
 import weakref
 import pickle
 import operator
+import re
 import struct
 import sys
 
@@ -110,6 +111,24 @@ def test_typecodes(self):
             self.assertIsInstance(typecode, str)
             self.assertGreaterEqual(len(typecode), 1)
 
+    @support.cpython_only
+    @support.requires_docstrings
+    def test_typecodes_documented(self):
+        # The type code table in the array.array docstring must list every
+        # supported type code, and nothing else, and the minimum size it
+        # gives for each of them must be one the implementation meets.
+        row = re.compile(r"^ {4}('\w+') +\S.*? +(\d+)(?: \(see note\))?$")
+        documented = {}
+        for line in array.array.__doc__.splitlines():
+            match = row.match(line)
+            if match is not None:
+                documented[match.group(1).strip("'")] = int(match.group(2))
+        self.assertEqual(sorted(documented), sorted(array.typecodes))
+        for typecode, minimum_size in documented.items():
+            with self.subTest(typecode=typecode):
+                self.assertGreaterEqual(array.array(typecode).itemsize,
+                                        minimum_size)
+
 
 # Machine format codes.
 #

Misc/NEWS.d/next/Documentation/2026-09-24-01-20-36.gh-issue-142083.WOlkvr.rst

@@ -0,0 +1,3 @@
+Document the ``'w'`` type code in the :class:`array.array` docstring, so
+that it lists the same type codes as :data:`array.typecodes` and the
+:mod:`array` module documentation.

Modules/arraymodule.c

@@ -3109,6 +3109,7 @@ The following type codes are defined:\n\
     Type code   C Type             Minimum size in bytes\n\
     'b'         signed integer     1\n\
     'B'         unsigned integer   1\n\
+    'w'         Py_UCS4            4\n\
     'h'         signed integer     2\n\
     'H'         unsigned integer   2\n\
     'i'         signed integer     2\n\