[Python-Dev] deprecating APIs

[Neal Norwitz]

Are we still planning to provide a mechanism to declare APIs, etc as
deprecated?

I have this code added to pyport.h which works for gcc:

    /* Py_DEPRECATED(version)
     * Declare a macro or function deprecated.
     * Usage:
     *    extern int old_var Py_DEPRECATED(2.3);
     *    typedef int T1 Py_DEPRECATED(2.4);
     *    extern int x() Py_DEPRECATED(2.5);
     */
    #if defined(__GNUC__) && (__GNUC__ == 3) && (__GNUC_MINOR__ >= 1)
    #define Py_DEPRECATED(VERSION_UNUSED) __attribute__((__deprecated__))
    #else
    #define Py_DEPRECATED(VERSION_UNUSED) 
    #endif

The version number is not necessary.  It is only for documentation.
I don't know how to support other compilers.

We could add Py_USE_DEPRECATED and/or Py_HIDE_DEPRECATED for
providing/hiding access to deprecated features.

    #ifdef Py_USE_DEPRECATED
    #define Py_SOME_DEPRECATED_MACRO
    #endif

or

    #ifndef Py_HIDE_DEPRECATED
    #define Py_SOME_DEPRECATED_MACRO
    #endif

Unfortunately, the Py_DEPRECATED macro doesn't work with macros, so we
would have to use Py_USE_DEPRECATED/Py_HIDE_DEPRECATED around
deprecated macros.

Neal