bpo-37330: open() no longer accept 'U' in file mode (GH-16959)

open(), io.open(), codecs.open() and fileinput.FileInput no longer
accept "U" ("universal newline") in the file mode. This flag was
deprecated since Python 3.3.

3 files changed, 11 insertions, 15 deletions

diff --git a/Doc/library/codecs.rst b/Doc/library/codecs.rst
index f071057..ec6a053 100644
--- a/Doc/library/codecs.rst
+++ b/Doc/library/codecs.rst
@@ -197,6 +197,9 @@ wider range of codecs when working with binary files:
    *buffering* has the same meaning as for the built-in :func:`open` function.
    It defaults to -1 which means that the default buffer size will be used.
 
+   .. versionchanged:: 3.9
+      The ``'U'`` mode has been removed.
+
 
 .. function:: EncodedFile(file, data_encoding, file_encoding=None, errors='strict')
 
diff --git a/Doc/library/fileinput.rst b/Doc/library/fileinput.rst
index f5e5280..8870c17 100644
--- a/Doc/library/fileinput.rst
+++ b/Doc/library/fileinput.rst
@@ -148,8 +148,8 @@ available for subclassing as well:
    The sequence must be accessed in strictly sequential order; random access
    and :meth:`~io.TextIOBase.readline` cannot be mixed.
 
-   With *mode* you can specify which file mode will be passed to :func:`open`. It
-   must be one of ``'r'``, ``'rU'``, ``'U'`` and ``'rb'``.
+   With *mode* you can specify which file mode will be passed to :func:`open`.
+   It must be ``'r'`` or ``'rb'``.
 
    The *openhook*, when given, must be a function that takes two arguments,
    *filename* and *mode*, and returns an accordingly opened file-like object. You
@@ -166,15 +166,14 @@ available for subclassing as well:
    .. versionchanged:: 3.2
       Can be used as a context manager.
 
-   .. deprecated:: 3.4
-      The ``'rU'`` and ``'U'`` modes.
-
    .. deprecated:: 3.8
       Support for :meth:`__getitem__` method is deprecated.
 
    .. versionchanged:: 3.8
       The keyword parameter *mode* and *openhook* are now keyword-only.
 
+   .. versionchanged:: 3.9
+      The ``'rU'`` and ``'U'`` modes have been removed.
 
 
 **Optional in-place filtering:** if the keyword argument ``inplace=True`` is
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 28d9c7b..acf922d 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -1085,12 +1085,6 @@ are always available.  They are listed here in alphabetical order.
    first decoded using a platform-dependent encoding or using the specified
    *encoding* if given.
 
-   There is an additional mode character permitted, ``'U'``, which no longer
-   has any effect, and is considered deprecated. It previously enabled
-   :term:`universal newlines` in text mode, which became the default behaviour
-   in Python 3.0. Refer to the documentation of the
-   :ref:`newline <open-newline-parameter>` parameter for further details.
-
    .. note::
 
       Python doesn't depend on the underlying operating system's notion of text
@@ -1247,10 +1241,6 @@ are always available.  They are listed here in alphabetical order.
 
          * The file is now non-inheritable.
 
-   .. deprecated-removed:: 3.4 4.0
-
-      The ``'U'`` mode.
-
    .. versionchanged::
       3.5
 
@@ -1266,6 +1256,10 @@ are always available.  They are listed here in alphabetical order.
          * On Windows, opening a console buffer may return a subclass of
            :class:`io.RawIOBase` other than :class:`io.FileIO`.
 
+   .. versionchanged:: 3.9
+      The ``'U'`` mode has been removed.
+
+
 .. function:: ord(c)
 
    Given a string representing one Unicode character, return an integer