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[Python-Dev] [Python-checkins] cpython: whatsnew: 'U' mode deprecation (#15204).

Nick Coghlan ncoghlan at gmail.com
Mon Mar 10 14:09:53 CET 2014 
On 10 Mar 2014 11:36, "r.david.murray" <python-checkins at python.org> wrote:
>
> http://hg.python.org/cpython/rev/2d5544afb510
> changeset:   89547:2d5544afb510
> user:        R David Murray <rdmurray at bitdance.com>
> date:        Sun Mar 09 20:33:35 2014 -0400
> summary:
>   whatsnew: 'U' mode deprecation (#15204).
>
> files:
>   Doc/whatsnew/3.4.rst |  14 +++++++++++++-
>   1 files changed, 13 insertions(+), 1 deletions(-)
>
>
> diff --git a/Doc/whatsnew/3.4.rst b/Doc/whatsnew/3.4.rst
> --- a/Doc/whatsnew/3.4.rst
> +++ b/Doc/whatsnew/3.4.rst
> @@ -1948,6 +1948,11 @@
>  * The :mod:`sysconfig` key ``SO`` is deprecated, it has been replaced by
>    ``EXT_SUFFIX``.
>
> +* The ``U`` mode accepted by various ``open`` functions is deprecated.
> +  In Python3 it does not do anything useful, and should be replaced by
> +  appropriate uses of :class:`io.TextIOWrapper` (if needed) and its
*newline*
> +  argument.
> +

Huh, I missed that change. Don't we still need U when writing 2/3
compatible code at this point? If so, perhaps we may want to reconsider
this particular deprecation in 3.4.1.

Cheers,
Nick.

>
>  Deprecations in the C API
>  -------------------------
> @@ -2242,7 +2247,14 @@
>
>  * Since the *digestmod* argument to the :func:`hmac.new` function will
in the
>    future have no default, all calls to :func:`hmac.new` should be
changed to
> -  explicitly specify a *digestmod*. (:issue:`17276`).
> +  explicitly specify a *digestmod* (:issue:`17276`).
> +
> +* Any calls to ``open`` functions that specify ``U`` should be modified.
> +  ``U`` is ineffective in Python3 and will eventually raise an error if
used.
> +  Depending on the function, the equivalent of its old Python2 behavior
can be
> +  achieved using either a *newline* argument, or if necessary by
wrapping the
> +  stream in :mod:`~io.TextIOWrapper` to use its *newline* argument
> +  (:issue:`15204`).
>
>
>  Changes in the C API
>
> --
> Repository URL: http://hg.python.org/cpython
>
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