Make all the multibyte codec tests pass.

Changes to io.py, necessary to make this work:
- Redid io.StringIO as a TextIOWrapper on top of a BytesIO instance.
- Got rid of _MemoryIOMixin, folding it into BytesIO instead.
- The read() functions that take -1 to mean "eveything" now also take None.
- Added readline() support to BufferedIOBase. :-(

Lib/io.py

@@ -415,8 +415,8 @@ class BufferedIOBase(IOBase):
     def read(self, n: int = -1) -> bytes:
         """read(n: int = -1) -> bytes.  Read and return up to n bytes.
 
-        If the argument is omitted, or negative, reads and returns all
-        data until EOF.
+        If the argument is omitted, None, or negative, reads and
+        returns all data until EOF.
 
         If the argument is positive, and the underlying raw stream is
         not 'interactive', multiple raw reads may be issued to satisfy
@@ -450,6 +450,20 @@ class BufferedIOBase(IOBase):
         b[:n] = data
         return n
 
+    def readline(self, sizehint: int = -1) -> bytes:
+        """For backwards compatibility, a (slow) readline()."""
+        if sizehint is None:
+            sizehint = -1
+        res = b""
+        while sizehint < 0 or len(res) < sizehint:
+            b = self.read(1)
+            if not b:
+                break
+            res += b
+            if b == b"\n":
+                break
+        return res
+
     def write(self, b: bytes) -> int:
         """write(b: bytes) -> int.  Write the given buffer to the IO stream.
 
@@ -518,19 +532,25 @@ class _BufferedIOMixin(BufferedIOBase):
         return self.raw.isatty()
 
 
-class _MemoryIOMixin(BufferedIOBase):
+class BytesIO(BufferedIOBase):
 
-    # XXX docstring
+    """Buffered I/O implementation using an in-memory bytes buffer."""
 
-    def __init__(self, buffer):
+    # XXX More docs
+
+    def __init__(self, initial_bytes=None):
+        buffer = b""
+        if initial_bytes is not None:
+            buffer += initial_bytes
         self._buffer = buffer
         self._pos = 0
 
     def getvalue(self):
         return self._buffer
 
-    def read(self, n=-1):
-        assert n is not None
+    def read(self, n=None):
+        if n is None:
+            n = -1
         if n < 0:
             n = len(self._buffer)
         newpos = min(len(self._buffer), self._pos + n)
@@ -538,6 +558,9 @@ class _MemoryIOMixin(BufferedIOBase):
         self._pos = newpos
         return b
 
+    def read1(self, n):
+        return self.read(n)
+
     def write(self, b):
         n = len(b)
         newpos = self._pos + n
@@ -575,65 +598,6 @@ class _MemoryIOMixin(BufferedIOBase):
         return True
 
 
-class BytesIO(_MemoryIOMixin):
-
-    """Buffered I/O implementation using a bytes buffer, like StringIO."""
-
-    # XXX More docs
-
-    def __init__(self, initial_bytes=None):
-        buffer = b""
-        if initial_bytes is not None:
-            buffer += initial_bytes
-        _MemoryIOMixin.__init__(self, buffer)
-
-
-# XXX This should inherit from TextIOBase
-class StringIO(_MemoryIOMixin):
-
-    """Buffered I/O implementation using a string buffer, like StringIO."""
-
-    # XXX More docs
-
-    # Reuses the same code as BytesIO, but encode strings on the way in
-    # and decode them on the way out.
-
-    charsize = len("!".encode("unicode-internal"))
-
-    def __init__(self, initial_string=None):
-        if initial_string is not None:
-            buffer = initial_string.encode("unicode-internal")
-        else:
-            buffer = b""
-        _MemoryIOMixin.__init__(self, buffer)
-
-    def getvalue(self):
-        return self._buffer.encode("unicode-internal")
-
-    def read(self, n=-1):
-        return super(StringIO, self).read(n*self.charsize) \
-                                    .decode("unicode-internal")
-
-    def write(self, s):
-        return super(StringIO, self).write(s.encode("unicode-internal")) \
-                                    //self.charsize
-
-    def seek(self, pos, whence=0):
-        return super(StringIO, self).seek(self.charsize*pos, whence) \
-                                    //self.charsize
-
-    def tell(self):
-        return super(StringIO, self).tell()//self.charsize
-
-    def truncate(self, pos=None):
-        if pos is not None:
-            pos *= self.charsize
-        return super(StringIO, self).truncate(pos)//self.charsize
-
-    def readinto(self, b: bytes) -> int:
-        self._unsupported("readinto")
-
-
 class BufferedReader(_BufferedIOMixin):
 
     """Buffer for a readable sequential RawIO object."""
@@ -646,7 +610,7 @@ class BufferedReader(_BufferedIOMixin):
         self._read_buf = b""
         self.buffer_size = buffer_size
 
-    def read(self, n=-1):
+    def read(self, n=None):
         """Read n bytes.
 
         Returns exactly n bytes of data unless the underlying raw IO
@@ -654,7 +618,8 @@ class BufferedReader(_BufferedIOMixin):
         mode. If n is negative, read until EOF or until read() would
         block.
         """
-        assert n is not None
+        if n is None:
+            n = -1
         nodata_val = b""
         while n < 0 or len(self._read_buf) < n:
             to_read = max(self.buffer_size,
@@ -801,7 +766,9 @@ class BufferedRWPair(BufferedIOBase):
         self.reader = BufferedReader(reader, buffer_size)
         self.writer = BufferedWriter(writer, buffer_size, max_buffer_size)
 
-    def read(self, n=-1):
+    def read(self, n=None):
+        if n is None:
+            n = -1
         return self.reader.read(n)
 
     def readinto(self, b):
@@ -861,7 +828,9 @@ class BufferedRandom(BufferedWriter, BufferedReader):
         else:
             return self.raw.tell() - len(self._read_buf)
 
-    def read(self, n=-1):
+    def read(self, n=None):
+        if n is None:
+            n = -1
         self.flush()
         return BufferedReader.read(self, n)
 
@@ -1129,7 +1098,9 @@ class TextIOWrapper(TextIOBase):
         except UnicodeEncodeError:
             return u
 
-    def read(self, n: int = -1):
+    def read(self, n=None):
+        if n is None:
+            n = -1
         decoder = self._decoder or self._get_decoder()
         res = self._pending
         if n < 0:
@@ -1146,7 +1117,7 @@ class TextIOWrapper(TextIOBase):
             self._pending = res[n:]
             return self._simplify(res[:n])
 
-    def __next__(self) -> str:
+    def __next__(self):
         self._telling = False
         line = self.readline()
         if not line:
@@ -1218,3 +1189,17 @@ class TextIOWrapper(TextIOBase):
             return self._simplify(line[:endpos] + "\n")
         else:
             return self._simplify(line[:nextpos])
+
+
+class StringIO(TextIOWrapper):
+
+    # XXX This is really slow, but fully functional
+
+    def __init__(self, initial_value=""):
+        super(StringIO, self).__init__(BytesIO(), "utf-8")
+        if initial_value:
+            self.write(initial_value)
+            self.seek(0)
+
+    def getvalue(self):
+        return self.buffer.getvalue().decode("utf-8")

Lib/test/test_codecencodings_cn.py

@@ -13,12 +13,12 @@ class Test_GB2312(test_multibytecodec_support.TestBase, unittest.TestCase):
     tstring = test_multibytecodec_support.load_teststring('gb2312')
     codectests = (
         # invalid bytes
-        ("abc\x81\x81\xc1\xc4", "strict",  None),
-        ("abc\xc8", "strict",  None),
-        ("abc\x81\x81\xc1\xc4", "replace", "abc\ufffd\u804a"),
-        ("abc\x81\x81\xc1\xc4\xc8", "replace", "abc\ufffd\u804a\ufffd"),
-        ("abc\x81\x81\xc1\xc4", "ignore",  "abc\u804a"),
-        ("\xc1\x64", "strict", None),
+        (b"abc\x81\x81\xc1\xc4", "strict",  None),
+        (b"abc\xc8", "strict",  None),
+        (b"abc\x81\x81\xc1\xc4", "replace", "abc\ufffd\u804a"),
+        (b"abc\x81\x81\xc1\xc4\xc8", "replace", "abc\ufffd\u804a\ufffd"),
+        (b"abc\x81\x81\xc1\xc4", "ignore",  "abc\u804a"),
+        (b"\xc1\x64", "strict", None),
     )
 
 class Test_GBK(test_multibytecodec_support.TestBase, unittest.TestCase):
@@ -26,12 +26,12 @@ class Test_GBK(test_multibytecodec_support.TestBase, unittest.TestCase):
     tstring = test_multibytecodec_support.load_teststring('gbk')
     codectests = (
         # invalid bytes
-        ("abc\x80\x80\xc1\xc4", "strict",  None),
-        ("abc\xc8", "strict",  None),
-        ("abc\x80\x80\xc1\xc4", "replace", "abc\ufffd\u804a"),
-        ("abc\x80\x80\xc1\xc4\xc8", "replace", "abc\ufffd\u804a\ufffd"),
-        ("abc\x80\x80\xc1\xc4", "ignore",  "abc\u804a"),
-        ("\x83\x34\x83\x31", "strict", None),
+        (b"abc\x80\x80\xc1\xc4", "strict",  None),
+        (b"abc\xc8", "strict",  None),
+        (b"abc\x80\x80\xc1\xc4", "replace", "abc\ufffd\u804a"),
+        (b"abc\x80\x80\xc1\xc4\xc8", "replace", "abc\ufffd\u804a\ufffd"),
+        (b"abc\x80\x80\xc1\xc4", "ignore",  "abc\u804a"),
+        (b"\x83\x34\x83\x31", "strict", None),
         ("\u30fb", "strict", None),
     )
 
@@ -40,13 +40,13 @@ class Test_GB18030(test_multibytecodec_support.TestBase, unittest.TestCase):
     tstring = test_multibytecodec_support.load_teststring('gb18030')
     codectests = (
         # invalid bytes
-        ("abc\x80\x80\xc1\xc4", "strict",  None),
-        ("abc\xc8", "strict",  None),
-        ("abc\x80\x80\xc1\xc4", "replace", "abc\ufffd\u804a"),
-        ("abc\x80\x80\xc1\xc4\xc8", "replace", "abc\ufffd\u804a\ufffd"),
-        ("abc\x80\x80\xc1\xc4", "ignore",  "abc\u804a"),
-        ("abc\x84\x39\x84\x39\xc1\xc4", "replace", "abc\ufffd\u804a"),
-        ("\u30fb", "strict", "\x819\xa79"),
+        (b"abc\x80\x80\xc1\xc4", "strict",  None),
+        (b"abc\xc8", "strict",  None),
+        (b"abc\x80\x80\xc1\xc4", "replace", "abc\ufffd\u804a"),
+        (b"abc\x80\x80\xc1\xc4\xc8", "replace", "abc\ufffd\u804a\ufffd"),
+        (b"abc\x80\x80\xc1\xc4", "ignore",  "abc\u804a"),
+        (b"abc\x84\x39\x84\x39\xc1\xc4", "replace", "abc\ufffd\u804a"),
+        ("\u30fb", "strict", b"\x819\xa79"),
     )
     has_iso10646 = True
 

Lib/test/test_codecencodings_hk.py

@@ -13,11 +13,11 @@ class Test_Big5HKSCS(test_multibytecodec_support.TestBase, unittest.TestCase):
     tstring = test_multibytecodec_support.load_teststring('big5hkscs')
     codectests = (
         # invalid bytes
-        ("abc\x80\x80\xc1\xc4", "strict",  None),
-        ("abc\xc8", "strict",  None),
-        ("abc\x80\x80\xc1\xc4", "replace", "abc\ufffd\u8b10"),
-        ("abc\x80\x80\xc1\xc4\xc8", "replace", "abc\ufffd\u8b10\ufffd"),
-        ("abc\x80\x80\xc1\xc4", "ignore",  "abc\u8b10"),
+        (b"abc\x80\x80\xc1\xc4", "strict",  None),
+        (b"abc\xc8", "strict",  None),
+        (b"abc\x80\x80\xc1\xc4", "replace", "abc\ufffd\u8b10"),
+        (b"abc\x80\x80\xc1\xc4\xc8", "replace", "abc\ufffd\u8b10\ufffd"),
+        (b"abc\x80\x80\xc1\xc4", "ignore",  "abc\u8b10"),
     )
 
 def test_main():

Lib/test/test_codecencodings_jp.py

@@ -13,14 +13,14 @@ class Test_CP932(test_multibytecodec_support.TestBase, unittest.TestCase):
     tstring = test_multibytecodec_support.load_teststring('shift_jis')
     codectests = (
         # invalid bytes
-        ("abc\x81\x00\x81\x00\x82\x84", "strict",  None),
-        ("abc\xf8", "strict",  None),
-        ("abc\x81\x00\x82\x84", "replace", "abc\ufffd\uff44"),
-        ("abc\x81\x00\x82\x84\x88", "replace", "abc\ufffd\uff44\ufffd"),
-        ("abc\x81\x00\x82\x84", "ignore",  "abc\uff44"),
+        (b"abc\x81\x00\x81\x00\x82\x84", "strict",  None),
+        (b"abc\xf8", "strict",  None),
+        (b"abc\x81\x00\x82\x84", "replace", "abc\ufffd\uff44"),
+        (b"abc\x81\x00\x82\x84\x88", "replace", "abc\ufffd\uff44\ufffd"),
+        (b"abc\x81\x00\x82\x84", "ignore",  "abc\uff44"),
         # sjis vs cp932
-        ("\\\x7e", "replace", "\\\x7e"),
-        ("\x81\x5f\x81\x61\x81\x7c", "replace", "\uff3c\u2225\uff0d"),
+        (b"\\\x7e", "replace", "\\\x7e"),
+        (b"\x81\x5f\x81\x61\x81\x7c", "replace", "\uff3c\u2225\uff0d"),
     )
 
 class Test_EUC_JISX0213(test_multibytecodec_support.TestBase,
@@ -29,28 +29,28 @@ class Test_EUC_JISX0213(test_multibytecodec_support.TestBase,
     tstring = test_multibytecodec_support.load_teststring('euc_jisx0213')
     codectests = (
         # invalid bytes
-        ("abc\x80\x80\xc1\xc4", "strict",  None),
-        ("abc\xc8", "strict",  None),
-        ("abc\x80\x80\xc1\xc4", "replace", "abc\ufffd\u7956"),
-        ("abc\x80\x80\xc1\xc4\xc8", "replace", "abc\ufffd\u7956\ufffd"),
-        ("abc\x80\x80\xc1\xc4", "ignore",  "abc\u7956"),
-        ("abc\x8f\x83\x83", "replace", "abc\ufffd"),
-        ("\xc1\x64", "strict", None),
-        ("\xa1\xc0", "strict", "\uff3c"),
+        (b"abc\x80\x80\xc1\xc4", "strict",  None),
+        (b"abc\xc8", "strict",  None),
+        (b"abc\x80\x80\xc1\xc4", "replace", "abc\ufffd\u7956"),
+        (b"abc\x80\x80\xc1\xc4\xc8", "replace", "abc\ufffd\u7956\ufffd"),
+        (b"abc\x80\x80\xc1\xc4", "ignore",  "abc\u7956"),
+        (b"abc\x8f\x83\x83", "replace", "abc\ufffd"),
+        (b"\xc1\x64", "strict", None),
+        (b"\xa1\xc0", "strict", "\uff3c"),
     )
     xmlcharnametest = (
         "\xab\u211c\xbb = \u2329\u1234\u232a",
-        "\xa9\xa8ℜ\xa9\xb2 = ⟨ሴ⟩"
+        b"\xa9\xa8ℜ\xa9\xb2 = ⟨ሴ⟩"
     )
 
 eucjp_commontests = (
-    ("abc\x80\x80\xc1\xc4", "strict",  None),
-    ("abc\xc8", "strict",  None),
-    ("abc\x80\x80\xc1\xc4", "replace", "abc\ufffd\u7956"),
-    ("abc\x80\x80\xc1\xc4\xc8", "replace", "abc\ufffd\u7956\ufffd"),
-    ("abc\x80\x80\xc1\xc4", "ignore",  "abc\u7956"),
-    ("abc\x8f\x83\x83", "replace", "abc\ufffd"),
-    ("\xc1\x64", "strict", None),
+    (b"abc\x80\x80\xc1\xc4", "strict",  None),
+    (b"abc\xc8", "strict",  None),
+    (b"abc\x80\x80\xc1\xc4", "replace", "abc\ufffd\u7956"),
+    (b"abc\x80\x80\xc1\xc4\xc8", "replace", "abc\ufffd\u7956\ufffd"),
+    (b"abc\x80\x80\xc1\xc4", "ignore",  "abc\u7956"),
+    (b"abc\x8f\x83\x83", "replace", "abc\ufffd"),
+    (b"\xc1\x64", "strict", None),
 )
 
 class Test_EUC_JP_COMPAT(test_multibytecodec_support.TestBase,
@@ -58,25 +58,25 @@ class Test_EUC_JP_COMPAT(test_multibytecodec_support.TestBase,
     encoding = 'euc_jp'
     tstring = test_multibytecodec_support.load_teststring('euc_jp')
     codectests = eucjp_commontests + (
-        ("\xa1\xc0\\", "strict", "\uff3c\\"),
-        ("\xa5", "strict", "\x5c"),
-        ("\u203e", "strict", "\x7e"),
+        (b"\xa1\xc0\\", "strict", "\uff3c\\"),
+        ("\xa5", "strict", b"\x5c"),
+        ("\u203e", "strict", b"\x7e"),
     )
 
 shiftjis_commonenctests = (
-    ("abc\x80\x80\x82\x84", "strict",  None),
-    ("abc\xf8", "strict",  None),
-    ("abc\x80\x80\x82\x84", "replace", "abc\ufffd\uff44"),
-    ("abc\x80\x80\x82\x84\x88", "replace", "abc\ufffd\uff44\ufffd"),
-    ("abc\x80\x80\x82\x84def", "ignore",  "abc\uff44def"),
+    (b"abc\x80\x80\x82\x84", "strict",  None),
+    (b"abc\xf8", "strict",  None),
+    (b"abc\x80\x80\x82\x84", "replace", "abc\ufffd\uff44"),
+    (b"abc\x80\x80\x82\x84\x88", "replace", "abc\ufffd\uff44\ufffd"),
+    (b"abc\x80\x80\x82\x84def", "ignore",  "abc\uff44def"),
 )
 
 class Test_SJIS_COMPAT(test_multibytecodec_support.TestBase, unittest.TestCase):
     encoding = 'shift_jis'
     tstring = test_multibytecodec_support.load_teststring('shift_jis')
     codectests = shiftjis_commonenctests + (
-        ("\\\x7e", "strict", "\\\x7e"),
-        ("\x81\x5f\x81\x61\x81\x7c", "strict", "\uff3c\u2016\u2212"),
+        (b"\\\x7e", "strict", "\\\x7e"),
+        (b"\x81\x5f\x81\x61\x81\x7c", "strict", "\uff3c\u2016\u2212"),
     )
 
 class Test_SJISX0213(test_multibytecodec_support.TestBase, unittest.TestCase):
@@ -84,18 +84,18 @@ class Test_SJISX0213(test_multibytecodec_support.TestBase, unittest.TestCase):
     tstring = test_multibytecodec_support.load_teststring('shift_jisx0213')
     codectests = (
         # invalid bytes
-        ("abc\x80\x80\x82\x84", "strict",  None),
-        ("abc\xf8", "strict",  None),
-        ("abc\x80\x80\x82\x84", "replace", "abc\ufffd\uff44"),
-        ("abc\x80\x80\x82\x84\x88", "replace", "abc\ufffd\uff44\ufffd"),
-        ("abc\x80\x80\x82\x84def", "ignore",  "abc\uff44def"),
+        (b"abc\x80\x80\x82\x84", "strict",  None),
+        (b"abc\xf8", "strict",  None),
+        (b"abc\x80\x80\x82\x84", "replace", "abc\ufffd\uff44"),
+        (b"abc\x80\x80\x82\x84\x88", "replace", "abc\ufffd\uff44\ufffd"),
+        (b"abc\x80\x80\x82\x84def", "ignore",  "abc\uff44def"),
         # sjis vs cp932
-        ("\\\x7e", "replace", "\xa5\u203e"),
-        ("\x81\x5f\x81\x61\x81\x7c", "replace", "\x5c\u2016\u2212"),
+        (b"\\\x7e", "replace", "\xa5\u203e"),
+        (b"\x81\x5f\x81\x61\x81\x7c", "replace", "\x5c\u2016\u2212"),
     )
     xmlcharnametest = (
         "\xab\u211c\xbb = \u2329\u1234\u232a",
-        "\x85Gℜ\x85Q = ⟨ሴ⟩"
+        b"\x85Gℜ\x85Q = ⟨ሴ⟩"
     )
 
 def test_main():

Lib/test/test_codecencodings_kr.py

@@ -13,11 +13,11 @@ class Test_CP949(test_multibytecodec_support.TestBase, unittest.TestCase):
     tstring = test_multibytecodec_support.load_teststring('cp949')
     codectests = (
         # invalid bytes
-        ("abc\x80\x80\xc1\xc4", "strict",  None),
-        ("abc\xc8", "strict",  None),
-        ("abc\x80\x80\xc1\xc4", "replace", "abc\ufffd\uc894"),
-        ("abc\x80\x80\xc1\xc4\xc8", "replace", "abc\ufffd\uc894\ufffd"),
-        ("abc\x80\x80\xc1\xc4", "ignore",  "abc\uc894"),
+        (b"abc\x80\x80\xc1\xc4", "strict",  None),
+        (b"abc\xc8", "strict",  None),
+        (b"abc\x80\x80\xc1\xc4", "replace", "abc\ufffd\uc894"),
+        (b"abc\x80\x80\xc1\xc4\xc8", "replace", "abc\ufffd\uc894\ufffd"),
+        (b"abc\x80\x80\xc1\xc4", "ignore",  "abc\uc894"),
     )
 
 class Test_EUCKR(test_multibytecodec_support.TestBase, unittest.TestCase):
@@ -25,11 +25,11 @@ class Test_EUCKR(test_multibytecodec_support.TestBase, unittest.TestCase):
     tstring = test_multibytecodec_support.load_teststring('euc_kr')
     codectests = (
         # invalid bytes
-        ("abc\x80\x80\xc1\xc4", "strict",  None),
-        ("abc\xc8", "strict",  None),
-        ("abc\x80\x80\xc1\xc4", "replace", "abc\ufffd\uc894"),
-        ("abc\x80\x80\xc1\xc4\xc8", "replace", "abc\ufffd\uc894\ufffd"),
-        ("abc\x80\x80\xc1\xc4", "ignore",  "abc\uc894"),
+        (b"abc\x80\x80\xc1\xc4", "strict",  None),
+        (b"abc\xc8", "strict",  None),
+        (b"abc\x80\x80\xc1\xc4", "replace", "abc\ufffd\uc894"),
+        (b"abc\x80\x80\xc1\xc4\xc8", "replace", "abc\ufffd\uc894\ufffd"),
+        (b"abc\x80\x80\xc1\xc4", "ignore",  "abc\uc894"),
     )
 
 class Test_JOHAB(test_multibytecodec_support.TestBase, unittest.TestCase):
@@ -37,11 +37,11 @@ class Test_JOHAB(test_multibytecodec_support.TestBase, unittest.TestCase):
     tstring = test_multibytecodec_support.load_teststring('johab')
     codectests = (
         # invalid bytes
-        ("abc\x80\x80\xc1\xc4", "strict",  None),
-        ("abc\xc8", "strict",  None),
-        ("abc\x80\x80\xc1\xc4", "replace", "abc\ufffd\ucd27"),
-        ("abc\x80\x80\xc1\xc4\xc8", "replace", "abc\ufffd\ucd27\ufffd"),
-        ("abc\x80\x80\xc1\xc4", "ignore",  "abc\ucd27"),
+        (b"abc\x80\x80\xc1\xc4", "strict",  None),
+        (b"abc\xc8", "strict",  None),
+        (b"abc\x80\x80\xc1\xc4", "replace", "abc\ufffd\ucd27"),
+        (b"abc\x80\x80\xc1\xc4\xc8", "replace", "abc\ufffd\ucd27\ufffd"),
+        (b"abc\x80\x80\xc1\xc4", "ignore",  "abc\ucd27"),
     )
 
 def test_main():

Lib/test/test_codecencodings_tw.py

@@ -13,11 +13,11 @@ class Test_Big5(test_multibytecodec_support.TestBase, unittest.TestCase):
     tstring = test_multibytecodec_support.load_teststring('big5')
     codectests = (
         # invalid bytes
-        ("abc\x80\x80\xc1\xc4", "strict",  None),
-        ("abc\xc8", "strict",  None),
-        ("abc\x80\x80\xc1\xc4", "replace", "abc\ufffd\u8b10"),
-        ("abc\x80\x80\xc1\xc4\xc8", "replace", "abc\ufffd\u8b10\ufffd"),
-        ("abc\x80\x80\xc1\xc4", "ignore",  "abc\u8b10"),
+        (b"abc\x80\x80\xc1\xc4", "strict",  None),
+        (b"abc\xc8", "strict",  None),
+        (b"abc\x80\x80\xc1\xc4", "replace", "abc\ufffd\u8b10"),
+        (b"abc\x80\x80\xc1\xc4\xc8", "replace", "abc\ufffd\u8b10\ufffd"),
+        (b"abc\x80\x80\xc1\xc4", "ignore",  "abc\u8b10"),
     )
 
 def test_main():

Lib/test/test_multibytecodec_support.py

@@ -7,12 +7,12 @@
 import sys, codecs, os.path
 import unittest
 from test import test_support
-from StringIO import StringIO
+from io import BytesIO
 
 class TestBase:
     encoding        = ''   # codec name
     codec           = None # codec tuple (with 4 elements)
-    tstring         = ''   # string to test StreamReader
+    tstring         = None # must set. 2 strings to test StreamReader
 
     codectests      = None # must set. codec test tuple
     roundtriptest   = 1    # set if roundtrip is possible with unicode
@@ -31,7 +31,7 @@ class TestBase:
         self.incrementaldecoder = self.codec.incrementaldecoder
 
     def test_chunkcoding(self):
-        for native, utf8 in zip(*[StringIO(f).readlines()
+        for native, utf8 in zip(*[map(bytes, str8(f).splitlines(1))
                                   for f in self.tstring]):
             u = self.decode(native)[0]
             self.assertEqual(u, utf8.decode('utf-8'))
@@ -40,7 +40,7 @@ class TestBase:
 
     def test_errorhandle(self):
         for source, scheme, expected in self.codectests:
-            if type(source) == type(''):
+            if isinstance(source, bytes):
                 func = self.decode
             else:
                 func = self.encode
@@ -57,7 +57,7 @@ class TestBase:
         s = "\u0b13\u0b23\u0b60 nd eggs"
         self.assertEqual(
             self.encode(s, "xmlcharrefreplace")[0],
-            "ଓଣୠ nd eggs"
+            b"ଓଣୠ nd eggs"
         )
 
     def test_customreplace_encode(self):
@@ -83,7 +83,7 @@ class TestBase:
             sin, sout = self.xmlcharnametest
         else:
             sin = "\xab\u211c\xbb = \u2329\u1234\u232a"
-            sout = "«ℜ» = ⟨ሴ⟩"
+            sout = b"«ℜ» = ⟨ሴ⟩"
         self.assertEqual(self.encode(sin,
                                     "test.xmlcharnamereplace")[0], sout)
 
@@ -92,7 +92,7 @@ class TestBase:
             return (ret, exc.end)
         codecs.register_error("test.cjktest", myreplace)
 
-        for ret in ([1, 2, 3], [], None, object(), 'string', ''):
+        for ret in ([1, 2, 3], [], None, object(), b'string', b''):
             self.assertRaises(TypeError, self.encode, self.unmappedunicode,
                               'test.cjktest')
 
@@ -101,7 +101,7 @@ class TestBase:
             return ('x', int(exc.end))
         codecs.register_error("test.cjktest", myreplace)
         self.assertEqual(self.encode('abcd' + self.unmappedunicode + 'efgh',
-                                     'test.cjktest'), ('abcdxefgh', 9))
+                                     'test.cjktest'), (b'abcdxefgh', 9))
 
         def myreplace(exc):
             return ('x', sys.maxint + 1)
@@ -127,14 +127,14 @@ class TestBase:
         codecs.register_error("test.cjktest", myreplace)
         self.assertEqual(self.encode('abcd' + self.unmappedunicode + 'efgh',
                                      'test.cjktest'),
-                ('abcdREPLACEDabcdREPLACEDabcdREPLACEDabcdTERMINALefgh', 9))
+                (b'abcdREPLACEDabcdREPLACEDabcdREPLACEDabcdTERMINALefgh', 9))
 
     def test_callback_forward_index(self):
         def myreplace(exc):
             return ('REPLACED', exc.end + 2)
         codecs.register_error("test.cjktest", myreplace)
         self.assertEqual(self.encode('abcd' + self.unmappedunicode + 'efgh',
-                                     'test.cjktest'), ('abcdREPLACEDgh', 9))
+                                     'test.cjktest'), (b'abcdREPLACEDgh', 9))
 
     def test_callback_index_outofbound(self):
         def myreplace(exc):
@@ -147,8 +147,8 @@ class TestBase:
         UTF8Reader = codecs.getreader('utf-8')
         for sizehint in [None] + list(range(1, 33)) + \
                         [64, 128, 256, 512, 1024]:
-            istream = UTF8Reader(StringIO(self.tstring[1]))
-            ostream = StringIO()
+            istream = UTF8Reader(BytesIO(self.tstring[1]))
+            ostream = BytesIO()
             encoder = self.incrementalencoder()
             while 1:
                 if sizehint is not None:
@@ -167,8 +167,8 @@ class TestBase:
         UTF8Writer = codecs.getwriter('utf-8')
         for sizehint in [None, -1] + list(range(1, 33)) + \
                         [64, 128, 256, 512, 1024]:
-            istream = StringIO(self.tstring[0])
-            ostream = UTF8Writer(StringIO())
+            istream = BytesIO(self.tstring[0])
+            ostream = UTF8Writer(BytesIO())
             decoder = self.incrementaldecoder()
             while 1:
                 data = istream.read(sizehint)
@@ -187,26 +187,26 @@ class TestBase:
         self.assertRaises(UnicodeEncodeError, e.encode, inv, True)
 
         e.errors = 'ignore'
-        self.assertEqual(e.encode(inv, True), '')
+        self.assertEqual(e.encode(inv, True), b'')
 
         e.reset()
         def tempreplace(exc):
             return ('called', exc.end)
         codecs.register_error('test.incremental_error_callback', tempreplace)
         e.errors = 'test.incremental_error_callback'
-        self.assertEqual(e.encode(inv, True), 'called')
+        self.assertEqual(e.encode(inv, True), b'called')
 
         # again
         e.errors = 'ignore'
-        self.assertEqual(e.encode(inv, True), '')
+        self.assertEqual(e.encode(inv, True), b'')
 
     def test_streamreader(self):
         UTF8Writer = codecs.getwriter('utf-8')
         for name in ["read", "readline", "readlines"]:
             for sizehint in [None, -1] + list(range(1, 33)) + \
                             [64, 128, 256, 512, 1024]:
-                istream = self.reader(StringIO(self.tstring[0]))
-                ostream = UTF8Writer(StringIO())
+                istream = self.reader(BytesIO(self.tstring[0]))
+                ostream = UTF8Writer(BytesIO())
                 func = getattr(istream, name)
                 while 1:
                     data = func(sizehint)
@@ -225,8 +225,8 @@ class TestBase:
         for name in readfuncs:
             for sizehint in [None] + list(range(1, 33)) + \
                             [64, 128, 256, 512, 1024]:
-                istream = UTF8Reader(StringIO(self.tstring[1]))
-                ostream = self.writer(StringIO())
+                istream = UTF8Reader(BytesIO(self.tstring[1]))
+                ostream = self.writer(BytesIO())
                 func = getattr(istream, name)
                 while 1:
                     if sizehint is not None:

Modules/cjkcodecs/multibytecodec.c

@@ -138,6 +138,11 @@ codecctx_errors_set(MultibyteStatefulCodecContext *self, PyObject *value,
 {
 	PyObject *cb;
 
+        if (PyUnicode_Check(value)) {
+		value = _PyUnicode_AsDefaultEncodedString(value, NULL);
+		if (value == NULL)
+			return -1;
+	}
 	if (!PyString_Check(value)) {
 		PyErr_SetString(PyExc_TypeError, "errors must be a string");
 		return -1;
@@ -322,11 +327,11 @@ multibytecodec_encerror(MultibyteCodec *codec,
 			goto errorexit;
 	}
 
-        assert(PyString_Check(retstr));
-	retstrsize = PyString_GET_SIZE(retstr);
+        assert(PyBytes_Check(retstr));
+	retstrsize = PyBytes_GET_SIZE(retstr);
 	REQUIRE_ENCODEBUFFER(buf, retstrsize);
 
-	memcpy(buf->outbuf, PyString_AS_STRING(retstr), retstrsize);
+	memcpy(buf->outbuf, PyBytes_AS_STRING(retstr), retstrsize);
 	buf->outbuf += retstrsize;
 
 	newpos = PyInt_AsSsize_t(PyTuple_GET_ITEM(retobj, 1));
@@ -1224,10 +1229,18 @@ mbstreamreader_iread(MultibyteStreamReaderObject *self,
 		if (cres == NULL)
 			goto errorexit;
 
+		if (PyString_Check(cres)) {
+			PyObject *cres2 = PyBytes_FromObject(cres);
+			if (cres2 == NULL)
+				return NULL;
+			Py_DECREF(cres);
+			cres = cres2;
+		}
+
 		if (!PyBytes_Check(cres)) {
 			PyErr_Format(PyExc_TypeError,
                                      "stream function returned a "
-                                     "non-string object (%.100s)",
+                                     "non-bytes object (%.100s)",
                                      cres->ob_type->tp_name);
 			goto errorexit;
 		}
@@ -1596,8 +1609,8 @@ mbstreamwriter_reset(MultibyteStreamWriterObject *self)
 	if (pwrt == NULL)
 		return NULL;
 
-        assert(PyString_Check(pwrt));
-	if (PyString_Size(pwrt) > 0) {
+        assert(PyBytes_Check(pwrt));
+	if (PyBytes_Size(pwrt) > 0) {
 		PyObject *wr;
 		wr = PyObject_CallMethod(self->stream, "write", "O", pwrt);
 		if (wr == NULL) {