bpo-42264: Deprecate sqlite3.OptimizedUnicode

Doc/whatsnew/3.10.rst

@@ -299,6 +299,10 @@ Deprecated
   as appropriate to help identify code which needs updating during
   this transition.
 
+* ``sqlite3.OptimizedUnicode`` has been deprecated. It has been undocumented
+  and obsolete since Python 3.3.
+  (Contributed by Erlend E. Aasland in :issue:`42264`.)
+
 
 Removed
 =======

Lib/sqlite3/__init__.py

@@ -20,4 +20,5 @@
 #    misrepresented as being the original software.
 # 3. This notice may not be removed or altered from any source distribution.
 
-from sqlite3.dbapi2 import *
+from .dbapi2 import *
+from .deprecated import __getattr__

Lib/sqlite3/deprecated.py

@@ -0,0 +1,10 @@
+def __getattr__(name):
+    if name == "OptimizedUnicode":
+        import warnings
+        msg = ("""
+            OptimizedUnicode is obsolete. You can safely remove it from your
+            code, as it defaults to 'str' anyway.
+        """)
+        warnings.warn(msg, DeprecationWarning)
+        return str
+    raise AttributeError(f"module 'sqlite3' has no attribute '{name}'")

Lib/sqlite3/test/factory.py

@@ -254,15 +254,13 @@ def CheckCustom(self):
         self.assertTrue(row[0].endswith("reich"), "column must contain original data")
 
     def CheckOptimizedUnicode(self):
-        # In py3k, str objects are always returned when text_factory
-        # is OptimizedUnicode
-        self.con.text_factory = sqlite.OptimizedUnicode
+        # OptimizedUnicode is deprecated as of Python 3.10
+        with self.assertWarns(DeprecationWarning):
+            self.con.text_factory = sqlite.OptimizedUnicode
         austria = "�sterreich"
         germany = "Deutchland"
-        a_row = self.con.execute("select ?", (austria,)).fetchone()
-        d_row = self.con.execute("select ?", (germany,)).fetchone()
-        self.assertEqual(type(a_row[0]), str, "type of non-ASCII row must be str")
-        self.assertEqual(type(d_row[0]), str, "type of ASCII-only row must be str")
+        self.con.execute("select ?", (austria,)).fetchone()
+        self.con.execute("select ?", (germany,)).fetchone()
 
     def tearDown(self):
         self.con.close()

Misc/NEWS.d/next/Library/2020-11-05-13-32-41.bpo-42264.r4KYUU.rst

@@ -0,0 +1 @@
+Deprecate ``sqlite3.OptimizedUnicode``

Modules/_sqlite/module.c

@@ -412,15 +412,6 @@ PyMODINIT_FUNC PyInit__sqlite3(void)
     ADD_EXCEPTION(module, "DataError", pysqlite_DataError, pysqlite_DatabaseError);
     ADD_EXCEPTION(module, "NotSupportedError", pysqlite_NotSupportedError, pysqlite_DatabaseError);
 
-    /* In Python 2.x, setting Connection.text_factory to
-       OptimizedUnicode caused Unicode objects to be returned for
-       non-ASCII data and bytestrings to be returned for ASCII data.
-       Now OptimizedUnicode is an alias for str, so it has no
-       effect. */
-    if (PyModule_AddObjectRef(module, "OptimizedUnicode", (PyObject*)&PyUnicode_Type) < 0) {
-        goto error;
-    }
-
     /* Set integer constants */
     if (add_integer_constants(module) < 0) {
         goto error;