python-peps/pep-0004.txt

PEP: 4
Title: Deprecation of Standard Modules
Version: $Revision$
Last-Modified: $Date$
Author: Martin v. Loewis <loewis@informatik.hu-berlin.de>
Status: Active
Type: Informational
Created: 1-Oct-2000

Introduction

    When new modules were added to the standard Python library in the
    past, it was not possible to foresee whether they would still be
    useful in the future.  Even though Python "Comes With Batteries
    Included", batteries may discharge over time.  Carrying old
    modules around is a burden on the maintainer, especially when
    there is no interest in the module anymore.

    At the same time, removing a module from the distribution is
    difficult, as it is not known in general whether anybody is still
    using it.  This PEP defines a procedure for removing modules from
    the standard Python library.  Usage of a module may be
    `deprecated', which means that it may be removed from a future
    Python release.  The rationale for deprecating a module is also
    collected in this PEP.  If the rationale turns out faulty, the
    module may become `undeprecated'.


Procedure for declaring a module deprecated

    Since the status of module deprecation is recorded in this PEP,
    proposals for deprecating modules MUST be made by providing a
    change to the text of this PEP, which SHOULD be a patch posted to
    SourceForge, or sent by mail to the author of this PEP.

    A proposal for deprecation of the module MUST include the date of
    the proposed deprecation and a rationale for deprecating it.  In
    addition, the proposal MUST include a change to the documentation
    of the module; deprecation is indicated by saying that the module
    is "obsolete" or "deprecated".  The proposal MAY include a patch
    for the module's source code to indicate deprecation there as
    well.

    It is expected that deprecated modules are included in the Python
    releases that immediately follows the deprecation; later releases
    may ship without the deprecated modules.


Procedure for declaring a module undeprecated

    When a module becomes deprecated, a rationale is given for its
    deprecation.  In some cases, an alternative interface for the same
    functionality is provided, so the old interface is deprecated.  In
    other cases, the need for having the functionality of the module
    may not exist anymore.

    If the rationale is faulty, again a change to this PEP's text MUST
    be submitted.  This change MUST include the date of undeprecation
    and a rationale for undeprecation.  Modules that are undeprecated
    under this procedure MUST be listed in this PEP for at least one
    major release of Python.


Obsolete modules

    A number of modules are already listed as obsolete in the library
    documentation.  These are listed here for completeness.

        cl, sv, timing

    All these modules have been declared as obsolete in Python 2.0,
    some even earlier.

    The following obsolte modules were removed in Python 2.5:

        addpack, cmp, cmpcache, codehack, dircmp, dump, find, fmt,
        grep, lockfile, newdir, ni, packmail, Para, poly,
        rand, reconvert, regex, regsub, statcache, tb, tzparse,
        util, whatsound, whrandom, zmod


Deprecated modules

    Module name:   posixfile
    Rationale:     Locking is better done by fcntl.lockf().
    Date:          Before 1-Oct-2000.
    Documentation: Already documented as obsolete.

    Module name:   gopherlib
    Rationale:     The gopher protocol is not in active use anymore.
    Date:          1-Oct-2000.
    Documentation: Documented as deprecated since Python 2.5.

    Module name:   rgbimgmodule
    Rationale:     In a 2001-04-24 c.l.py post, Jason Petrone mentions
                   that he occasionally uses it; no other references to 
                   its use can be found as of 2003-11-19.
    Date:          1-Oct-2000
    Documentation: Documented as deprecated since Python 2.5.

    Module name:   pre
    Rationale:     The underlying PCRE engine doesn't support Unicode, and 
                   has been unmaintained since Python 1.5.2.
    Date:          10-Apr-2002
    Documentation: It was only mentioned as an implementation detail, 
                   and never had a section of its own.   This mention
                   has now been removed.

    Module name:   whrandom
    Rationale:     The module's default seed computation was
                   inherently insecure; the random module should be
                   used instead.
    Date:          11-Apr-2002
    Documentation: This module has been documented as obsolete since
                   Python 2.1, but listing in this PEP was neglected.
                   The deprecation warning will be added to the module
                   one year after Python 2.3 is released, and the
                   module will be removed one year after that.

    Module name:   rfc822
    Rationale:     Supplanted by Python 2.2's email package.
    Date:          18-Mar-2002
    Documentation: Documented as "deprecated since release 2.3" since
                   Python 2.2.2.

    Module name:   mimetools
    Rationale:     Supplanted by Python 2.2's email package.
    Date:          18-Mar-2002
    Documentation: Documented as "deprecated since release 2.3" since
                   Python 2.2.2.

    Module name:   MimeWriter
    Rationale:     Supplanted by Python 2.2's email package.
    Date:          18-Mar-2002
    Documentation: Documented as "deprecated since release 2.3" since
                   Python 2.2.2.

    Module name:   mimify
    Rationale:     Supplanted by Python 2.2's email package.
    Date:          18-Mar-2002
    Documentation: Documented as "deprecated since release 2.3" since
                   Python 2.2.2.

    Module name:   rotor
    Rationale:     Uses insecure algorithm.
    Date:          24-Apr-2003
    Documentation: The documentation has been removed from the library
                   reference in Python 2.4.

    Module name:   TERMIOS.py
    Rationale:     The constants in this file are now in the 'termios' module.
    Date:          10-Aug-2004
    Documentation: This module has been documented as obsolete since
                   Python 2.1, but listing in this PEP was neglected.
                   Removed from the library reference in Python 2.4.

    Module name:   statcache
    Rationale:     Using the cache can be fragile and error-prone;
                   applications should just use os.stat() directly.
    Date:          10-Aug-2004
    Documentation: This module has been documented as obsolete since
                   Python 2.2, but listing in this PEP was neglected.
                   Removed from the library reference in Python 2.5.

    Module name:   mpz
    Rationale:     Third-party packages provide similiar features
                   and wrap more of GMP's API.
    Date:          10-Aug-2004
    Documentation: This module has been documented as obsolete since
                   Python 2.2, but listing in this PEP was neglected.
                   Removed from the library reference in Python 2.4.

    Module name:   xreadlines
    Rationale:     Using 'for line in file', introduced in 2.3, is preferable.
    Date:          10-Aug-2004
    Documentation: This module has been documented as obsolete since
                   Python 2.3, but listing in this PEP was neglected.
                   Removed from the library reference in Python 2.4.

    Module name:   multifile
    Rationale:     Supplanted by the email package.
    Date:          21-Feb-2006
    Documentation: Documented as deprecated as of Python 2.5.


Undeprecated modules

    None.



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