Revert my commit 3555cf6f9c98: "Issue #8796: codecs.open() calls the builtin

open() function instead of using StreamReaderWriter. Deprecate StreamReader,
StreamWriter, StreamReaderWriter, StreamRecoder and EncodedFile() of the codec
module. Use the builtin open() function or io.TextIOWrapper instead."

"It has not been approved !" wrote Marc-Andre Lemburg.

Doc/library/codecs.rst

@@ -85,9 +85,6 @@ It defines the following functions:
    In case a search function cannot find a given encoding, it should return
    ``None``.
 
-   .. deprecated:: 3.3
-      *streamreader* and *streamwriter* attributes are now deprecated.
-
 
 .. function:: lookup(encoding)
 
@@ -142,8 +139,6 @@ functions which use :func:`lookup` for the codec lookup:
 
    Raises a :exc:`LookupError` in case the encoding cannot be found.
 
-   .. deprecated:: 3.3
-
 
 .. function:: getwriter(encoding)
 
@@ -152,8 +147,6 @@ functions which use :func:`lookup` for the codec lookup:
 
    Raises a :exc:`LookupError` in case the encoding cannot be found.
 
-   .. deprecated:: 3.3
-
 
 .. function:: register_error(name, error_handler)
 
@@ -222,11 +215,6 @@ utility functions:
    providing transparent encoding/decoding.  The default file mode is ``'r'``
    meaning to open the file in read mode.
 
-   .. note::
-
-      This function is kept for backward compatibility with Python 2, the
-      builtin :func:`open` function should be used instead.
-
    .. note::
 
       The wrapped version's methods will accept and return strings only.  Bytes
@@ -263,8 +251,6 @@ utility functions:
    ``'strict'``, which causes :exc:`ValueError` to be raised in case an encoding
    error occurs.
 
-   .. deprecated:: 3.3
-
 
 .. function:: iterencode(iterator, encoding, errors='strict', **kwargs)
 
@@ -577,9 +563,6 @@ The :class:`StreamWriter` class is a subclass of :class:`Codec` and defines the
 following methods which every stream writer must define in order to be
 compatible with the Python codec registry.
 
-.. deprecated:: 3.3
-   Use the builtin the :class:`io.TextIOWrapper` class.
-
 
 .. class:: StreamWriter(stream[, errors])
 
@@ -645,9 +628,6 @@ The :class:`StreamReader` class is a subclass of :class:`Codec` and defines the
 following methods which every stream reader must define in order to be
 compatible with the Python codec registry.
 
-.. deprecated:: 3.3
-   Use the builtin the :class:`io.TextIOWrapper` class.
-
 
 .. class:: StreamReader(stream[, errors])
 
@@ -748,9 +728,6 @@ and write modes.
 The design is such that one can use the factory functions returned by the
 :func:`lookup` function to construct the instance.
 
-.. deprecated:: 3.3
-   Use the :class:`io.TextIOWrapper` class.
-
 
 .. class:: StreamReaderWriter(stream, Reader, Writer, errors)
 
@@ -775,8 +752,6 @@ which is sometimes useful when dealing with different encoding environments.
 The design is such that one can use the factory functions returned by the
 :func:`lookup` function to construct the instance.
 
-.. deprecated:: 3.3
-
 
 .. class:: StreamRecoder(stream, encode, decode, Reader, Writer, errors)
 

Lib/codecs.py

@@ -345,8 +345,6 @@ class StreamWriter(Codec):
             The set of allowed parameter values can be extended via
             register_error.
         """
-        import warnings
-        warnings.warn('use io.TextIOWrapper', DeprecationWarning, stacklevel=2)
         self.stream = stream
         self.errors = errors
 
@@ -418,8 +416,6 @@ class StreamReader(Codec):
             The set of allowed parameter values can be extended via
             register_error.
         """
-        import warnings
-        warnings.warn('use io.TextIOWrapper', DeprecationWarning, stacklevel=2)
         self.stream = stream
         self.errors = errors
         self.bytebuffer = b""
@@ -850,7 +846,7 @@ class StreamRecoder:
 
 ### Shortcuts
 
-def open(filename, mode='r', encoding=None, errors=None, buffering=1):
+def open(filename, mode='rb', encoding=None, errors='strict', buffering=1):
 
     """ Open an encoded file using the given mode and return
         a wrapped version providing transparent encoding/decoding.
@@ -881,13 +877,18 @@ def open(filename, mode='r', encoding=None, errors=None, buffering=1):
         parameter.
 
     """
-    if encoding is not None:
-        return builtins.open(filename, mode, buffering,
-                             encoding, errors, newline='')
-    else:
-        if 'b' not in mode:
+    if encoding is not None and \
+       'b' not in mode:
+        # Force opening of the file in binary mode
         mode = mode + 'b'
-        return builtins.open(filename, mode, buffering, encoding, errors)
+    file = builtins.open(filename, mode, buffering)
+    if encoding is None:
+        return file
+    info = lookup(encoding)
+    srw = StreamReaderWriter(file, info.streamreader, info.streamwriter, errors)
+    # Add attributes to simplify introspection
+    srw.encoding = encoding
+    return srw
 
 def EncodedFile(file, data_encoding, file_encoding=None, errors='strict'):
 

Lib/test/test_codecs.py

 from test import support
-import _testcapi
-import codecs
-import io
-import sys
 import unittest
-import warnings
+import codecs
+import sys, _testcapi, io
 
 class Queue(object):
     """
@@ -66,8 +63,6 @@ class ReadTest(unittest.TestCase, MixInCheckStateHandling):
         # the StreamReader and check that the results equal the appropriate
         # entries from partialresults.
         q = Queue(b"")
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         r = codecs.getreader(self.encoding)(q)
         result = ""
         for (c, partialresult) in zip(input.encode(self.encoding), partialresults):
@@ -111,8 +106,6 @@ class ReadTest(unittest.TestCase, MixInCheckStateHandling):
             return codecs.getreader(self.encoding)(stream)
 
         def readalllines(input, keepends=True, size=None):
-            with warnings.catch_warnings():
-                warnings.simplefilter("ignore", DeprecationWarning)
             reader = getreader(input)
             lines = []
             while True:
@@ -222,16 +215,12 @@ class ReadTest(unittest.TestCase, MixInCheckStateHandling):
             '                \r\n',
         ]
         stream = io.BytesIO("".join(s).encode(self.encoding))
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         reader = codecs.getreader(self.encoding)(stream)
         for (i, line) in enumerate(reader):
             self.assertEqual(line, s[i])
 
     def test_readlinequeue(self):
         q = Queue(b"")
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         writer = codecs.getwriter(self.encoding)(q)
         reader = codecs.getreader(self.encoding)(q)
 
@@ -264,8 +253,6 @@ class ReadTest(unittest.TestCase, MixInCheckStateHandling):
 
         s = (s1+s2+s3).encode(self.encoding)
         stream = io.BytesIO(s)
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         reader = codecs.getreader(self.encoding)(stream)
         self.assertEqual(reader.readline(), s1)
         self.assertEqual(reader.readline(), s2)
@@ -281,8 +268,6 @@ class ReadTest(unittest.TestCase, MixInCheckStateHandling):
 
         s = (s1+s2+s3+s4+s5).encode(self.encoding)
         stream = io.BytesIO(s)
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         reader = codecs.getreader(self.encoding)(stream)
         self.assertEqual(reader.readline(), s1)
         self.assertEqual(reader.readline(), s2)
@@ -305,8 +290,6 @@ class UTF32Test(ReadTest):
         _,_,reader,writer = codecs.lookup(self.encoding)
         # encode some stream
         s = io.BytesIO()
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         f = writer(s)
         f.write("spam")
         f.write("spam")
@@ -315,21 +298,15 @@ class UTF32Test(ReadTest):
         self.assertTrue(d == self.spamle or d == self.spambe)
         # try to read it back
         s = io.BytesIO(d)
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         f = reader(s)
         self.assertEqual(f.read(), "spamspam")
 
     def test_badbom(self):
         s = io.BytesIO(4*b"\xff")
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         f = codecs.getreader(self.encoding)(s)
         self.assertRaises(UnicodeError, f.read)
 
         s = io.BytesIO(8*b"\xff")
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         f = codecs.getreader(self.encoding)(s)
         self.assertRaises(UnicodeError, f.read)
 
@@ -477,8 +454,6 @@ class UTF16Test(ReadTest):
         _,_,reader,writer = codecs.lookup(self.encoding)
         # encode some stream
         s = io.BytesIO()
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         f = writer(s)
         f.write("spam")
         f.write("spam")
@@ -487,21 +462,15 @@ class UTF16Test(ReadTest):
         self.assertTrue(d == self.spamle or d == self.spambe)
         # try to read it back
         s = io.BytesIO(d)
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         f = reader(s)
         self.assertEqual(f.read(), "spamspam")
 
     def test_badbom(self):
         s = io.BytesIO(b"\xff\xff")
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         f = codecs.getreader(self.encoding)(s)
         self.assertRaises(UnicodeError, f.read)
 
         s = io.BytesIO(b"\xff\xff\xff\xff")
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         f = codecs.getreader(self.encoding)(s)
         self.assertRaises(UnicodeError, f.read)
 
@@ -548,8 +517,7 @@ class UTF16Test(ReadTest):
         self.addCleanup(support.unlink, support.TESTFN)
         with open(support.TESTFN, 'wb') as fp:
             fp.write(s)
-        with codecs.open(support.TESTFN, 'U',
-                         encoding=self.encoding) as reader:
+        with codecs.open(support.TESTFN, 'U', encoding=self.encoding) as reader:
             self.assertEqual(reader.read(), s1)
 
 class UTF16LETest(ReadTest):
@@ -737,8 +705,6 @@ class UTF8SigTest(ReadTest):
         reader = codecs.getreader("utf-8-sig")
         for sizehint in [None] + list(range(1, 11)) + \
                         [64, 128, 256, 512, 1024]:
-            with warnings.catch_warnings():
-                warnings.simplefilter("ignore", DeprecationWarning)
             istream = reader(io.BytesIO(bytestring))
             ostream = io.StringIO()
             while 1:
@@ -761,8 +727,6 @@ class UTF8SigTest(ReadTest):
         reader = codecs.getreader("utf-8-sig")
         for sizehint in [None] + list(range(1, 11)) + \
                         [64, 128, 256, 512, 1024]:
-            with warnings.catch_warnings():
-                warnings.simplefilter("ignore", DeprecationWarning)
             istream = reader(io.BytesIO(bytestring))
             ostream = io.StringIO()
             while 1:
@@ -785,8 +749,6 @@ class EscapeDecodeTest(unittest.TestCase):
 class RecodingTest(unittest.TestCase):
     def test_recoding(self):
         f = io.BytesIO()
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         f2 = codecs.EncodedFile(f, "unicode_internal", "utf-8")
         f2.write("a")
         f2.close()
@@ -1164,8 +1126,6 @@ class IDNACodecTest(unittest.TestCase):
         self.assertEqual("pyth\xf6n.org.".encode("idna"), b"xn--pythn-mua.org.")
 
     def test_stream(self):
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         r = codecs.getreader("idna")(io.BytesIO(b"abc"))
         r.read(3)
         self.assertEqual(r.read(), "")
@@ -1273,14 +1233,10 @@ class CodecsModuleTest(unittest.TestCase):
 class StreamReaderTest(unittest.TestCase):
 
     def setUp(self):
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         self.reader = codecs.getreader('utf-8')
         self.stream = io.BytesIO(b'\xed\x95\x9c\n\xea\xb8\x80')
 
     def test_readlines(self):
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         f = self.reader(self.stream)
         self.assertEqual(f.readlines(), ['\ud55c\n', '\uae00'])
 
@@ -1288,8 +1244,6 @@ class EncodedFileTest(unittest.TestCase):
 
     def test_basic(self):
         f = io.BytesIO(b'\xed\x95\x9c\n\xea\xb8\x80')
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         ef = codecs.EncodedFile(f, 'utf-16-le', 'utf-8')
         self.assertEqual(ef.read(), b'\\\xd5\n\x00\x00\xae')
 
@@ -1434,8 +1388,6 @@ class BasicUnicodeTest(unittest.TestCase, MixInCheckStateHandling):
             if encoding not in broken_unicode_with_streams:
                 # check stream reader/writer
                 q = Queue(b"")
-                with warnings.catch_warnings():
-                    warnings.simplefilter("ignore", DeprecationWarning)
                 writer = codecs.getwriter(encoding)(q)
                 encodedresult = b""
                 for c in s:
@@ -1444,8 +1396,6 @@ class BasicUnicodeTest(unittest.TestCase, MixInCheckStateHandling):
                     self.assertTrue(type(chunk) is bytes, type(chunk))
                     encodedresult += chunk
                 q = Queue(b"")
-                with warnings.catch_warnings():
-                    warnings.simplefilter("ignore", DeprecationWarning)
                 reader = codecs.getreader(encoding)(q)
                 decodedresult = ""
                 for c in encodedresult:
@@ -1520,8 +1470,6 @@ class BasicUnicodeTest(unittest.TestCase, MixInCheckStateHandling):
                 continue
             if encoding in broken_unicode_with_streams:
                 continue
-            with warnings.catch_warnings():
-                warnings.simplefilter("ignore", DeprecationWarning)
             reader = codecs.getreader(encoding)(io.BytesIO(s.encode(encoding)))
             for t in range(5):
                 # Test that calling seek resets the internal codec state and buffers
@@ -1591,16 +1539,12 @@ class CharmapTest(unittest.TestCase):
 class WithStmtTest(unittest.TestCase):
     def test_encodedfile(self):
         f = io.BytesIO(b"\xc3\xbc")
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         with codecs.EncodedFile(f, "latin-1", "utf-8") as ef:
             self.assertEqual(ef.read(), b"\xfc")
 
     def test_streamreaderwriter(self):
         f = io.BytesIO(b"\xc3\xbc")
         info = codecs.lookup("utf-8")
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore", DeprecationWarning)
         with codecs.StreamReaderWriter(f, info.streamreader,
                                        info.streamwriter, 'strict') as srw:
             self.assertEqual(srw.read(), "\xfc")
@@ -1700,15 +1644,15 @@ class BomTest(unittest.TestCase):
 
             # (StreamWriter) Check that the BOM is written after a seek(0)
             with codecs.open(support.TESTFN, 'w+', encoding=encoding) as f:
-                f.write(data[0])
-                self.assertNotEqual(f.tell(), 0)
-                f.seek(0)
-                f.write(data)
+                f.writer.write(data[0])
+                self.assertNotEqual(f.writer.tell(), 0)
+                f.writer.seek(0)
+                f.writer.write(data)
                 f.seek(0)
                 self.assertEqual(f.read(), data)
 
-            # Check that the BOM is not written after a seek() at a
-            # position different than the start
+            # Check that the BOM is not written after a seek() at a position
+            # different than the start
             with codecs.open(support.TESTFN, 'w+', encoding=encoding) as f:
                 f.write(data)
                 f.seek(f.tell())
@@ -1716,12 +1660,12 @@ class BomTest(unittest.TestCase):
                 f.seek(0)
                 self.assertEqual(f.read(), data * 2)
 
-            # (StreamWriter) Check that the BOM is not written after a
-            # seek() at a position different than the start
+            # (StreamWriter) Check that the BOM is not written after a seek()
+            # at a position different than the start
             with codecs.open(support.TESTFN, 'w+', encoding=encoding) as f:
-                f.write(data)
-                f.seek(f.tell())
-                f.write(data)
+                f.writer.write(data)
+                f.writer.seek(f.writer.tell())
+                f.writer.write(data)
                 f.seek(0)
                 self.assertEqual(f.read(), data * 2)
 
@@ -1760,8 +1704,6 @@ class TransformCodecTest(unittest.TestCase):
     def test_read(self):
         for encoding in bytes_transform_encodings:
             sin = codecs.encode(b"\x80", encoding)
-            with warnings.catch_warnings():
-                warnings.simplefilter("ignore", DeprecationWarning)
             reader = codecs.getreader(encoding)(io.BytesIO(sin))
             sout = reader.read()
             self.assertEqual(sout, b"\x80")
@@ -1771,8 +1713,6 @@ class TransformCodecTest(unittest.TestCase):
             if encoding in ['uu_codec', 'zlib_codec']:
                 continue
             sin = codecs.encode(b"\x80", encoding)
-            with warnings.catch_warnings():
-                warnings.simplefilter("ignore", DeprecationWarning)
             reader = codecs.getreader(encoding)(io.BytesIO(sin))
             sout = reader.readline()
             self.assertEqual(sout, b"\x80")

Misc/NEWS

@@ -167,11 +167,6 @@ Library
 - Issue #1625: BZ2File and bz2.decompress() now support multi-stream files.
   Initial patch by Nir Aides.
 
-- Issue #8796: codecs.open() calls the builtin open() function instead of using
-  StreamReaderWriter. Deprecate StreamReader, StreamWriter, StreamReaderWriter,
-  StreamRecoder and EncodedFile() of the codec module. Use the builtin open()
-  function or io.TextIOWrapper instead.
-
 - Issue #12175: BufferedReader.read(-1) now calls raw.readall() if available.
 
 - Issue #12175: FileIO.readall() now only reads the file position and size