gh-142083: Document the 'w' type code in the array.array docstring (#158040)

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.

(cherry picked from commit ab01d18)

Author: v0ropaev

Lib/test/test_array.py

@@ -12,6 +12,7 @@
 import weakref
 import pickle
 import operator
+import re
 import struct
 import sys
 import warnings
@@ -117,6 +118,25 @@ 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)] = 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

@@ -3200,6 +3200,7 @@ The following type codes are defined:\n\
     'b'         signed integer     1\n\
     'B'         unsigned integer   1\n\
     'u'         Unicode character  2 (see note)\n\
+    'w'         Py_UCS4            4\n\
     'h'         signed integer     2\n\
     'H'         unsigned integer   2\n\
     'i'         signed integer     2\n\