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.

Doc/library/codecs.rst

@@ -85,6 +85,9 @@ 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)
 
@@ -139,6 +142,8 @@ 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)
 
@@ -147,6 +152,8 @@ 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)
 
@@ -215,6 +222,11 @@ 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
@@ -251,6 +263,8 @@ 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)
 
@@ -563,6 +577,9 @@ 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])
 
@@ -628,6 +645,9 @@ 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])
 
@@ -728,6 +748,9 @@ 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)
 
@@ -752,6 +775,8 @@ 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

@@ -345,6 +345,8 @@ 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
 
@@ -416,6 +418,8 @@ 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""
@@ -846,7 +850,7 @@ class StreamRecoder:
 
 ### Shortcuts
 
-def open(filename, mode='rb', encoding=None, errors='strict', buffering=1):
+def open(filename, mode='r', encoding=None, errors=None, buffering=1):
 
     """ Open an encoded file using the given mode and return
         a wrapped version providing transparent encoding/decoding.
@@ -877,18 +881,13 @@ def open(filename, mode='rb', encoding=None, errors='strict', buffering=1):
         parameter.
 
     """
-    if encoding is not None and \
-       'b' not in mode:
-        # Force opening of the file in binary mode
-        mode = mode + 'b'
-    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
+    if encoding is not None:
+        return builtins.open(filename, mode, buffering,
+                             encoding, errors, newline='')
+    else:
+        if 'b' not in mode:
+            mode = mode + 'b'
+        return builtins.open(filename, mode, buffering, encoding, errors)
 
 def EncodedFile(file, data_encoding, file_encoding=None, errors='strict'):
 

Misc/NEWS

@@ -161,6 +161,11 @@ Core and Builtins
 Library
 -------
 
+- 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