gh-111495: Add tests for `PyCodec_*` C API (#123343)

Lib/test/test_capi/test_codecs.py

@@ -1,13 +1,20 @@
-import unittest
+import codecs
+import contextlib
+import io
+import re
 import sys
+import unittest
+import unittest.mock as mock
+import _testcapi
 from test.support import import_helper
 
 _testlimitedcapi = import_helper.import_module('_testlimitedcapi')
 
 NULL = None
+BAD_ARGUMENT = re.escape('bad argument type for built-in operation')
 
 
-class CAPITest(unittest.TestCase):
+class CAPIUnicodeTest(unittest.TestCase):
     # TODO: Test the following functions:
     #
     #   PyUnicode_BuildEncodingMap
@@ -516,5 +523,291 @@ class CAPITest(unittest.TestCase):
         # CRASHES asrawunicodeescapestring(NULL)
 
 
+class CAPICodecs(unittest.TestCase):
+
+    def setUp(self):
+        # Encoding names are normalized internally by converting them
+        # to lowercase and their hyphens are replaced by underscores.
+        self.encoding_name = 'test.test_capi.test_codecs.codec_reversed'
+        # Make sure that our custom codec is not already registered (that
+        # way we know whether we correctly unregistered the custom codec
+        # after a test or not).
+        self.assertRaises(LookupError, codecs.lookup, self.encoding_name)
+        # create the search function without registering yet
+        self._create_custom_codec()
+
+    def _create_custom_codec(self):
+        def codec_encoder(m, errors='strict'):
+            return (type(m)().join(reversed(m)), len(m))
+
+        def codec_decoder(c, errors='strict'):
+            return (type(c)().join(reversed(c)), len(c))
+
+        class IncrementalEncoder(codecs.IncrementalEncoder):
+            def encode(self, input, final=False):
+                return codec_encoder(input)
+
+        class IncrementalDecoder(codecs.IncrementalDecoder):
+            def decode(self, input, final=False):
+                return codec_decoder(input)
+
+        class StreamReader(codecs.StreamReader):
+            def encode(self, input, errors='strict'):
+                return codec_encoder(input, errors=errors)
+
+            def decode(self, input, errors='strict'):
+                return codec_decoder(input, errors=errors)
+
+        class StreamWriter(codecs.StreamWriter):
+            def encode(self, input, errors='strict'):
+                return codec_encoder(input, errors=errors)
+
+            def decode(self, input, errors='strict'):
+                return codec_decoder(input, errors=errors)
+
+        info = codecs.CodecInfo(
+            encode=codec_encoder,
+            decode=codec_decoder,
+            streamreader=StreamReader,
+            streamwriter=StreamWriter,
+            incrementalencoder=IncrementalEncoder,
+            incrementaldecoder=IncrementalDecoder,
+            name=self.encoding_name
+        )
+
+        def search_function(encoding):
+            if encoding == self.encoding_name:
+                return info
+            return None
+
+        self.codec_info = info
+        self.search_function = search_function
+
+    @contextlib.contextmanager
+    def use_custom_encoder(self):
+        self.assertRaises(LookupError, codecs.lookup, self.encoding_name)
+        codecs.register(self.search_function)
+        yield
+        codecs.unregister(self.search_function)
+        self.assertRaises(LookupError, codecs.lookup, self.encoding_name)
+
+    def test_codec_register(self):
+        search_function, encoding = self.search_function, self.encoding_name
+        # register the search function using the C API
+        self.assertIsNone(_testcapi.codec_register(search_function))
+        # in case the test failed before cleaning up
+        self.addCleanup(codecs.unregister, self.search_function)
+        self.assertIs(codecs.lookup(encoding), search_function(encoding))
+        self.assertEqual(codecs.encode('123', encoding=encoding), '321')
+        # unregister the search function using the regular API
+        codecs.unregister(search_function)
+        self.assertRaises(LookupError, codecs.lookup, encoding)
+
+    def test_codec_unregister(self):
+        search_function, encoding = self.search_function, self.encoding_name
+        self.assertRaises(LookupError, codecs.lookup, encoding)
+        # register the search function using the regular API
+        codecs.register(search_function)
+        # in case the test failed before cleaning up
+        self.addCleanup(codecs.unregister, self.search_function)
+        self.assertIsNotNone(codecs.lookup(encoding))
+        # unregister the search function using the C API
+        self.assertIsNone(_testcapi.codec_unregister(search_function))
+        self.assertRaises(LookupError, codecs.lookup, encoding)
+
+    def test_codec_known_encoding(self):
+        self.assertRaises(LookupError, codecs.lookup, 'unknown-codec')
+        self.assertFalse(_testcapi.codec_known_encoding('unknown-codec'))
+        self.assertFalse(_testcapi.codec_known_encoding('unknown_codec'))
+        self.assertFalse(_testcapi.codec_known_encoding('UNKNOWN-codec'))
+
+        encoding_name = self.encoding_name
+        self.assertRaises(LookupError, codecs.lookup, encoding_name)
+
+        codecs.register(self.search_function)
+        self.addCleanup(codecs.unregister, self.search_function)
+
+        for name in [
+            encoding_name,
+            encoding_name.upper(),
+            encoding_name.replace('_', '-'),
+        ]:
+            with self.subTest(name):
+                self.assertTrue(_testcapi.codec_known_encoding(name))
+
+    def test_codec_encode(self):
+        encode = _testcapi.codec_encode
+        self.assertEqual(encode('a', 'utf-8', NULL), b'a')
+        self.assertEqual(encode('a', 'utf-8', 'strict'), b'a')
+        self.assertEqual(encode('[é]', 'ascii', 'ignore'), b'[]')
+
+        self.assertRaises(TypeError, encode, NULL, 'ascii', 'strict')
+        with self.assertRaisesRegex(TypeError, BAD_ARGUMENT):
+            encode('a', NULL, 'strict')
+
+    def test_codec_decode(self):
+        decode = _testcapi.codec_decode
+
+        s = 'a\xa1\u4f60\U0001f600'
+        b = s.encode()
+
+        self.assertEqual(decode(b, 'utf-8', 'strict'), s)
+        self.assertEqual(decode(b, 'utf-8', NULL), s)
+        self.assertEqual(decode(b, 'latin1', 'strict'), b.decode('latin1'))
+        self.assertRaises(UnicodeDecodeError, decode, b, 'ascii', 'strict')
+        self.assertRaises(UnicodeDecodeError, decode, b, 'ascii', NULL)
+        self.assertEqual(decode(b, 'ascii', 'replace'), 'a' + '\ufffd'*9)
+
+        # _codecs.decode() only reports an unknown error handling name when
+        # the corresponding error handling function is used; this difers
+        # from PyUnicode_Decode() which checks that both the encoding and
+        # the error handling name are recognized before even attempting to
+        # call the decoder.
+        self.assertEqual(decode(b'', 'utf-8', 'unknown-error-handler'), '')
+        self.assertEqual(decode(b'a', 'utf-8', 'unknown-error-handler'), 'a')
+
+        self.assertRaises(TypeError, decode, NULL, 'ascii', 'strict')
+        with self.assertRaisesRegex(TypeError, BAD_ARGUMENT):
+            decode(b, NULL, 'strict')
+
+    def test_codec_encoder(self):
+        codec_encoder = _testcapi.codec_encoder
+
+        with self.use_custom_encoder():
+            encoder = codec_encoder(self.encoding_name)
+            self.assertIs(encoder, self.codec_info.encode)
+
+            with self.assertRaisesRegex(TypeError, BAD_ARGUMENT):
+                codec_encoder(NULL)
+
+    def test_codec_decoder(self):
+        codec_decoder = _testcapi.codec_decoder
+
+        with self.use_custom_encoder():
+            decoder = codec_decoder(self.encoding_name)
+            self.assertIs(decoder, self.codec_info.decode)
+
+            with self.assertRaisesRegex(TypeError, BAD_ARGUMENT):
+                codec_decoder(NULL)
+
+    def test_codec_incremental_encoder(self):
+        codec_incremental_encoder = _testcapi.codec_incremental_encoder
+
+        with self.use_custom_encoder():
+            encoding = self.encoding_name
+
+            for errors in ['strict', NULL]:
+                with self.subTest(errors):
+                    encoder = codec_incremental_encoder(encoding, errors)
+                    self.assertIsInstance(encoder, self.codec_info.incrementalencoder)
+
+            with self.assertRaisesRegex(TypeError, BAD_ARGUMENT):
+                codec_incremental_encoder(NULL, 'strict')
+
+    def test_codec_incremental_decoder(self):
+        codec_incremental_decoder = _testcapi.codec_incremental_decoder
+
+        with self.use_custom_encoder():
+            encoding = self.encoding_name
+
+            for errors in ['strict', NULL]:
+                with self.subTest(errors):
+                    decoder = codec_incremental_decoder(encoding, errors)
+                    self.assertIsInstance(decoder, self.codec_info.incrementaldecoder)
+
+            with self.assertRaisesRegex(TypeError, BAD_ARGUMENT):
+                codec_incremental_decoder(NULL, 'strict')
+
+    def test_codec_stream_reader(self):
+        codec_stream_reader = _testcapi.codec_stream_reader
+
+        with self.use_custom_encoder():
+            encoding, stream = self.encoding_name, io.StringIO()
+            for errors in ['strict', NULL]:
+                with self.subTest(errors):
+                    writer = codec_stream_reader(encoding, stream, errors)
+                    self.assertIsInstance(writer, self.codec_info.streamreader)
+
+            with self.assertRaisesRegex(TypeError, BAD_ARGUMENT):
+                codec_stream_reader(NULL, stream, 'strict')
+
+    def test_codec_stream_writer(self):
+        codec_stream_writer = _testcapi.codec_stream_writer
+
+        with self.use_custom_encoder():
+            encoding, stream = self.encoding_name, io.StringIO()
+            for errors in ['strict', NULL]:
+                with self.subTest(errors):
+                    writer = codec_stream_writer(encoding, stream, errors)
+                    self.assertIsInstance(writer, self.codec_info.streamwriter)
+
+            with self.assertRaisesRegex(TypeError, BAD_ARGUMENT):
+                codec_stream_writer(NULL, stream, 'strict')
+
+
+class CAPICodecErrors(unittest.TestCase):
+
+    def test_codec_register_error(self):
+        # for cleaning up between tests
+        from _codecs import _unregister_error as _codecs_unregister_error
+
+        self.assertRaises(LookupError, _testcapi.codec_lookup_error, 'custom')
+
+        def custom_error_handler(exc):
+            raise exc
+
+        error_handler = mock.Mock(wraps=custom_error_handler)
+        _testcapi.codec_register_error('custom', error_handler)
+        self.addCleanup(_codecs_unregister_error, 'custom')
+
+        self.assertRaises(UnicodeEncodeError, codecs.encode,
+                          '\xff', 'ascii', errors='custom')
+        error_handler.assert_called_once()
+        error_handler.reset_mock()
+
+        self.assertRaises(UnicodeDecodeError, codecs.decode,
+                          b'\xff', 'ascii', errors='custom')
+        error_handler.assert_called_once()
+
+    # _codecs._unregister_error directly delegates to the internal C
+    # function so a Python-level function test is sufficient (it is
+    # tested in test_codeccallbacks).
+
+    def test_codec_lookup_error(self):
+        codec_lookup_error = _testcapi.codec_lookup_error
+        self.assertIs(codec_lookup_error(NULL), codecs.strict_errors)
+        self.assertIs(codec_lookup_error('strict'), codecs.strict_errors)
+        self.assertIs(codec_lookup_error('ignore'), codecs.ignore_errors)
+        self.assertIs(codec_lookup_error('replace'), codecs.replace_errors)
+        self.assertIs(codec_lookup_error('xmlcharrefreplace'), codecs.xmlcharrefreplace_errors)
+        self.assertIs(codec_lookup_error('namereplace'), codecs.namereplace_errors)
+        self.assertRaises(LookupError, codec_lookup_error, 'unknown')
+
+    def test_codec_error_handlers(self):
+        exceptions = [
+            # A UnicodeError with an empty message currently crashes:
+            # See: https://github.com/python/cpython/issues/123378
+            # UnicodeEncodeError('bad', '', 0, 1, 'reason'),
+            UnicodeEncodeError('bad', 'x', 0, 1, 'reason'),
+            UnicodeEncodeError('bad', 'xyz123', 0, 1, 'reason'),
+            UnicodeEncodeError('bad', 'xyz123', 1, 4, 'reason'),
+        ]
+
+        strict_handler = _testcapi.codec_strict_errors
+        for exc in exceptions:
+            with self.subTest(handler=strict_handler, exc=exc):
+                self.assertRaises(UnicodeEncodeError, strict_handler, exc)
+
+        for handler in [
+            _testcapi.codec_ignore_errors,
+            _testcapi.codec_replace_errors,
+            _testcapi.codec_xmlcharrefreplace_errors,
+            _testlimitedcapi.codec_namereplace_errors,
+        ]:
+            for exc in exceptions:
+                with self.subTest(handler=handler, exc=exc):
+                    self.assertIsInstance(handler(exc), tuple)
+
+
 if __name__ == "__main__":
     unittest.main()

Modules/Setup.stdlib.in

@@ -163,7 +163,7 @@
 @MODULE__TESTBUFFER_TRUE@_testbuffer _testbuffer.c
 @MODULE__TESTINTERNALCAPI_TRUE@_testinternalcapi _testinternalcapi.c _testinternalcapi/test_lock.c _testinternalcapi/pytime.c _testinternalcapi/set.c _testinternalcapi/test_critical_sections.c
 @MODULE__TESTCAPI_TRUE@_testcapi _testcapimodule.c _testcapi/vectorcall.c _testcapi/heaptype.c _testcapi/abstract.c _testcapi/unicode.c _testcapi/dict.c _testcapi/set.c _testcapi/list.c _testcapi/tuple.c _testcapi/getargs.c _testcapi/datetime.c _testcapi/docstring.c _testcapi/mem.c _testcapi/watchers.c _testcapi/long.c _testcapi/float.c _testcapi/complex.c _testcapi/numbers.c _testcapi/structmember.c _testcapi/exceptions.c _testcapi/code.c _testcapi/buffer.c _testcapi/pyatomic.c _testcapi/run.c _testcapi/file.c _testcapi/codec.c _testcapi/immortal.c _testcapi/gc.c _testcapi/hash.c _testcapi/time.c _testcapi/bytes.c _testcapi/object.c _testcapi/monitoring.c  _testcapi/config.c
-@MODULE__TESTLIMITEDCAPI_TRUE@_testlimitedcapi _testlimitedcapi.c _testlimitedcapi/abstract.c _testlimitedcapi/bytearray.c _testlimitedcapi/bytes.c _testlimitedcapi/complex.c _testlimitedcapi/dict.c _testlimitedcapi/eval.c _testlimitedcapi/float.c _testlimitedcapi/heaptype_relative.c _testlimitedcapi/list.c _testlimitedcapi/long.c _testlimitedcapi/object.c _testlimitedcapi/pyos.c _testlimitedcapi/set.c _testlimitedcapi/sys.c _testlimitedcapi/tuple.c _testlimitedcapi/unicode.c _testlimitedcapi/vectorcall_limited.c
+@MODULE__TESTLIMITEDCAPI_TRUE@_testlimitedcapi _testlimitedcapi.c _testlimitedcapi/abstract.c _testlimitedcapi/bytearray.c _testlimitedcapi/bytes.c _testlimitedcapi/codec.c _testlimitedcapi/complex.c _testlimitedcapi/dict.c _testlimitedcapi/eval.c _testlimitedcapi/float.c _testlimitedcapi/heaptype_relative.c _testlimitedcapi/list.c _testlimitedcapi/long.c _testlimitedcapi/object.c _testlimitedcapi/pyos.c _testlimitedcapi/set.c _testlimitedcapi/sys.c _testlimitedcapi/tuple.c _testlimitedcapi/unicode.c _testlimitedcapi/vectorcall_limited.c
 @MODULE__TESTCLINIC_TRUE@_testclinic _testclinic.c
 @MODULE__TESTCLINIC_LIMITED_TRUE@_testclinic_limited _testclinic_limited.c
 

Modules/_testcapi/codec.c

@@ -1,9 +1,213 @@
 #include "parts.h"
 #include "util.h"
 
+// === Codecs registration and un-registration ================================
+
+static PyObject *
+codec_register(PyObject *Py_UNUSED(module), PyObject *search_function)
+{
+    if (PyCodec_Register(search_function) < 0) {
+        return NULL;
+    }
+    Py_RETURN_NONE;
+}
+
+static PyObject *
+codec_unregister(PyObject *Py_UNUSED(module), PyObject *search_function)
+{
+    if (PyCodec_Unregister(search_function) < 0) {
+        return NULL;
+    }
+    Py_RETURN_NONE;
+}
+
+static PyObject *
+codec_known_encoding(PyObject *Py_UNUSED(module), PyObject *args)
+{
+    const char *NULL_WOULD_RAISE(encoding); // NULL case will be tested
+    if (!PyArg_ParseTuple(args, "z", &encoding)) {
+        return NULL;
+    }
+    return PyCodec_KnownEncoding(encoding) ? Py_True : Py_False;
+}
+
+// === Codecs encoding and decoding interfaces ================================
+
+static PyObject *
+codec_encode(PyObject *Py_UNUSED(module), PyObject *args)
+{
+    PyObject *input;
+    const char *NULL_WOULD_RAISE(encoding); // NULL case will be tested
+    const char *errors;                     // can be NULL
+    if (!PyArg_ParseTuple(args, "O|zz", &input, &encoding, &errors)) {
+        return NULL;
+    }
+    return PyCodec_Encode(input, encoding, errors);
+}
+
+static PyObject *
+codec_decode(PyObject *Py_UNUSED(module), PyObject *args)
+{
+    PyObject *input;
+    const char *NULL_WOULD_RAISE(encoding); // NULL case will be tested
+    const char *errors;                     // can be NULL
+    if (!PyArg_ParseTuple(args, "O|zz", &input, &encoding, &errors)) {
+        return NULL;
+    }
+    return PyCodec_Decode(input, encoding, errors);
+}
+
+static PyObject *
+codec_encoder(PyObject *Py_UNUSED(module), PyObject *args)
+{
+    const char *NULL_WOULD_RAISE(encoding); // NULL case will be tested
+    if (!PyArg_ParseTuple(args, "z", &encoding)) {
+        return NULL;
+    }
+    return PyCodec_Encoder(encoding);
+}
+
+static PyObject *
+codec_decoder(PyObject *Py_UNUSED(module), PyObject *args)
+{
+    const char *NULL_WOULD_RAISE(encoding); // NULL case will be tested
+    if (!PyArg_ParseTuple(args, "z", &encoding)) {
+        return NULL;
+    }
+    return PyCodec_Decoder(encoding);
+}
+
+static PyObject *
+codec_incremental_encoder(PyObject *Py_UNUSED(module), PyObject *args)
+{
+    const char *NULL_WOULD_RAISE(encoding); // NULL case will be tested
+    const char *errors;                     // can be NULL
+    if (!PyArg_ParseTuple(args, "zz", &encoding, &errors)) {
+        return NULL;
+    }
+    return PyCodec_IncrementalEncoder(encoding, errors);
+}
+
+static PyObject *
+codec_incremental_decoder(PyObject *Py_UNUSED(module), PyObject *args)
+{
+    const char *NULL_WOULD_RAISE(encoding); // NULL case will be tested
+    const char *errors;                     // can be NULL
+    if (!PyArg_ParseTuple(args, "zz", &encoding, &errors)) {
+        return NULL;
+    }
+    return PyCodec_IncrementalDecoder(encoding, errors);
+}
+
+static PyObject *
+codec_stream_reader(PyObject *Py_UNUSED(module), PyObject *args)
+{
+    const char *NULL_WOULD_RAISE(encoding); // NULL case will be tested
+    PyObject *stream;
+    const char *errors;                     // can be NULL
+    if (!PyArg_ParseTuple(args, "zOz", &encoding, &stream, &errors)) {
+        return NULL;
+    }
+    return PyCodec_StreamReader(encoding, stream, errors);
+}
+
+static PyObject *
+codec_stream_writer(PyObject *Py_UNUSED(module), PyObject *args)
+{
+    const char *NULL_WOULD_RAISE(encoding); // NULL case will be tested
+    PyObject *stream;
+    const char *errors;                     // can be NULL
+    if (!PyArg_ParseTuple(args, "zOz", &encoding, &stream, &errors)) {
+        return NULL;
+    }
+    return PyCodec_StreamWriter(encoding, stream, errors);
+}
+
+// === Codecs errors handlers =================================================
+
+static PyObject *
+codec_register_error(PyObject *Py_UNUSED(module), PyObject *args)
+{
+    const char *encoding;   // must not be NULL
+    PyObject *error;
+    if (!PyArg_ParseTuple(args, "sO", &encoding, &error)) {
+        return NULL;
+    }
+    if (PyCodec_RegisterError(encoding, error) < 0) {
+        return NULL;
+    }
+    Py_RETURN_NONE;
+}
+
+static PyObject *
+codec_lookup_error(PyObject *Py_UNUSED(module), PyObject *args)
+{
+    const char *NULL_WOULD_RAISE(encoding); // NULL case will be tested
+    if (!PyArg_ParseTuple(args, "z", &encoding)) {
+        return NULL;
+    }
+    return PyCodec_LookupError(encoding);
+}
+
+static PyObject *
+codec_strict_errors(PyObject *Py_UNUSED(module), PyObject *exc)
+{
+    assert(exc != NULL);
+    return PyCodec_StrictErrors(exc);
+}
+
+static PyObject *
+codec_ignore_errors(PyObject *Py_UNUSED(module), PyObject *exc)
+{
+    assert(exc != NULL);
+    return PyCodec_IgnoreErrors(exc);
+}
+
+static PyObject *
+codec_replace_errors(PyObject *Py_UNUSED(module), PyObject *exc)
+{
+    assert(exc != NULL);
+    return PyCodec_ReplaceErrors(exc);
+}
+
+static PyObject *
+codec_xmlcharrefreplace_errors(PyObject *Py_UNUSED(module), PyObject *exc)
+{
+    assert(exc != NULL);
+    return PyCodec_XMLCharRefReplaceErrors(exc);
+}
+
+static PyObject *
+codec_backslashreplace_errors(PyObject *Py_UNUSED(module), PyObject *exc)
+{
+    assert(exc != NULL);
+    return PyCodec_BackslashReplaceErrors(exc);
+}
 
 static PyMethodDef test_methods[] = {
-    {NULL},
+    /* codecs registration */
+    {"codec_register", codec_register, METH_O},
+    {"codec_unregister", codec_unregister, METH_O},
+    {"codec_known_encoding", codec_known_encoding, METH_VARARGS},
+    /* encoding and decoding interface */
+    {"codec_encode", codec_encode, METH_VARARGS},
+    {"codec_decode", codec_decode, METH_VARARGS},
+    {"codec_encoder", codec_encoder, METH_VARARGS},
+    {"codec_decoder", codec_decoder, METH_VARARGS},
+    {"codec_incremental_encoder", codec_incremental_encoder, METH_VARARGS},
+    {"codec_incremental_decoder", codec_incremental_decoder, METH_VARARGS},
+    {"codec_stream_reader", codec_stream_reader, METH_VARARGS},
+    {"codec_stream_writer", codec_stream_writer, METH_VARARGS},
+    /* error handling */
+    {"codec_register_error", codec_register_error, METH_VARARGS},
+    {"codec_lookup_error", codec_lookup_error, METH_VARARGS},
+    {"codec_strict_errors", codec_strict_errors, METH_O},
+    {"codec_ignore_errors", codec_ignore_errors, METH_O},
+    {"codec_replace_errors", codec_replace_errors, METH_O},
+    {"codec_xmlcharrefreplace_errors", codec_xmlcharrefreplace_errors, METH_O},
+    {"codec_backslashreplace_errors", codec_backslashreplace_errors, METH_O},
+    // PyCodec_NameReplaceErrors() is tested in _testlimitedcapi/codec.c
+    {NULL, NULL, 0, NULL},
 };
 
 int

Modules/_testcapi/util.h

@@ -31,3 +31,13 @@ static const char uninitialized[] = "uninitialized";
 #define UNINITIALIZED_SIZE ((Py_ssize_t)236892191)
 /* Marker to check that integer value was set. */
 #define UNINITIALIZED_INT (63256717)
+/*
+ * Marker to indicate that a NULL parameter would not be allowed
+ * at runtime but that the test interface will check that it is
+ * indeed the case.
+ *
+ * Use this macro only if passing NULL to the C API would raise
+ * a catchable exception (and not a fatal exception that would
+ * crash the interpreter).
+ */
+ #define NULL_WOULD_RAISE(NAME)    NAME

Modules/_testlimitedcapi.c

@@ -38,6 +38,9 @@ PyInit__testlimitedcapi(void)
     if (_PyTestLimitedCAPI_Init_Bytes(mod) < 0) {
         return NULL;
     }
+    if (_PyTestLimitedCAPI_Init_Codec(mod) < 0) {
+        return NULL;
+    }
     if (_PyTestLimitedCAPI_Init_Complex(mod) < 0) {
         return NULL;
     }

Modules/_testlimitedcapi/codec.c

@@ -0,0 +1,29 @@
+#include "pyconfig.h"   // Py_GIL_DISABLED
+
+// Need limited C API version 3.5 for PyCodec_NameReplaceErrors()
+#if !defined(Py_GIL_DISABLED) && !defined(Py_LIMITED_API)
+#  define Py_LIMITED_API 0x03050000
+#endif
+
+#include "parts.h"
+
+static PyObject *
+codec_namereplace_errors(PyObject *Py_UNUSED(module), PyObject *exc)
+{
+    assert(exc != NULL);
+    return PyCodec_NameReplaceErrors(exc);
+}
+
+static PyMethodDef test_methods[] = {
+    {"codec_namereplace_errors", codec_namereplace_errors, METH_O},
+    {NULL},
+};
+
+int
+_PyTestLimitedCAPI_Init_Codec(PyObject *module)
+{
+    if (PyModule_AddFunctions(module, test_methods) < 0) {
+        return -1;
+    }
+    return 0;
+}

Modules/_testlimitedcapi/parts.h

@@ -25,6 +25,7 @@
 int _PyTestLimitedCAPI_Init_Abstract(PyObject *module);
 int _PyTestLimitedCAPI_Init_ByteArray(PyObject *module);
 int _PyTestLimitedCAPI_Init_Bytes(PyObject *module);
+int _PyTestLimitedCAPI_Init_Codec(PyObject *module);
 int _PyTestLimitedCAPI_Init_Complex(PyObject *module);
 int _PyTestLimitedCAPI_Init_Dict(PyObject *module);
 int _PyTestLimitedCAPI_Init_Eval(PyObject *module);

PCbuild/_testlimitedcapi.vcxproj

@@ -97,6 +97,7 @@
     <ClCompile Include="..\Modules\_testlimitedcapi\abstract.c" />
     <ClCompile Include="..\Modules\_testlimitedcapi\bytearray.c" />
     <ClCompile Include="..\Modules\_testlimitedcapi\bytes.c" />
+    <ClCompile Include="..\Modules\_testlimitedcapi\codec.c" />
     <ClCompile Include="..\Modules\_testlimitedcapi\complex.c" />
     <ClCompile Include="..\Modules\_testlimitedcapi\dict.c" />
     <ClCompile Include="..\Modules\_testlimitedcapi\eval.c" />

PCbuild/_testlimitedcapi.vcxproj.filters

@@ -12,6 +12,7 @@
     <ClCompile Include="..\Modules\_testlimitedcapi\abstract.c" />
     <ClCompile Include="..\Modules\_testlimitedcapi\bytearray.c" />
     <ClCompile Include="..\Modules\_testlimitedcapi\bytes.c" />
+    <ClCompile Include="..\Modules\_testlimitedcapi\codec.c" />
     <ClCompile Include="..\Modules\_testlimitedcapi\complex.c" />
     <ClCompile Include="..\Modules\_testlimitedcapi\dict.c" />
     <ClCompile Include="..\Modules\_testlimitedcapi\eval.c" />