gh-105145: Remove old functions to config Python init (#105154)

Remove the following old functions to configure the Python
initialization, deprecated in Python 3.11:

* PySys_AddWarnOptionUnicode()
* PySys_AddWarnOption()
* PySys_AddXOption()
* PySys_HasWarnOptions()
* PySys_SetArgvEx()
* PySys_SetArgv()
* PySys_SetPath()
* Py_SetPath()
* Py_SetProgramName()
* Py_SetPythonHome()
* Py_SetStandardStreamEncoding()
* _Py_SetProgramFullPath()

Most of these functions are kept in the stable ABI, except:

* Py_SetStandardStreamEncoding()
* _Py_SetProgramFullPath()

Update Doc/extending/embedding.rst and Doc/extending/extending.rst to
use the new PyConfig API.

_testembed.c:

* check_stdio_details() now sets stdio_encoding and stdio_errors
  of PyConfig.
* Add definitions of functions removed from the API but kept in the
  stable ABI.
* test_init_from_config() and test_init_read_set() now use
  PyConfig_SetString() instead of PyConfig_SetBytesString().

Remove _Py_ClearStandardStreamEncoding() internal function.

Author: vstinner

Doc/c-api/init.rst

@@ -29,12 +29,6 @@ The following functions can be safely called before Python is initialized:
   * :c:func:`PyMem_SetAllocator`
   * :c:func:`PyMem_SetupDebugHooks`
   * :c:func:`PyObject_SetArenaAllocator`
-  * :c:func:`Py_SetPath`
-  * :c:func:`Py_SetProgramName`
-  * :c:func:`Py_SetPythonHome`
-  * :c:func:`Py_SetStandardStreamEncoding`
-  * :c:func:`PySys_AddWarnOption`
-  * :c:func:`PySys_AddXOption`
   * :c:func:`PySys_ResetWarnOptions`
 
 * Informative functions:
@@ -332,16 +326,13 @@ Initializing and finalizing the interpreter
 .. c:function:: void Py_Initialize()
 
    .. index::
-      single: Py_SetProgramName()
       single: PyEval_InitThreads()
       single: modules (in module sys)
       single: path (in module sys)
       pair: module; builtins
       pair: module; __main__
       pair: module; sys
       triple: module; search; path
-      single: PySys_SetArgv()
-      single: PySys_SetArgvEx()
       single: Py_FinalizeEx()
 
    Initialize the Python interpreter.  In an application embedding  Python,
@@ -352,7 +343,9 @@ Initializing and finalizing the interpreter
    the table of loaded modules (``sys.modules``), and creates the fundamental
    modules :mod:`builtins`, :mod:`__main__` and :mod:`sys`.  It also initializes
    the module search path (``sys.path``). It does not set ``sys.argv``; use
-   :c:func:`PySys_SetArgvEx` for that.  This is a no-op when called for a second time
+   the new :c:type:`PyConfig` API of the :ref:`Python Initialization
+   Configuration <init-config>` for that.  This is a no-op when called for a
+   second time
    (without calling :c:func:`Py_FinalizeEx` first).  There is no return value; it is a
    fatal error if the initialization fails.
 
@@ -425,76 +418,9 @@ Process-wide parameters
 =======================
 
 
-.. c:function:: int Py_SetStandardStreamEncoding(const char *encoding, const char *errors)
-
-   .. index::
-      single: Py_Initialize()
-      single: main()
-      triple: stdin; stdout; sdterr
-
-   This API is kept for backward compatibility: setting
-   :c:member:`PyConfig.stdio_encoding` and :c:member:`PyConfig.stdio_errors`
-   should be used instead, see :ref:`Python Initialization Configuration
-   <init-config>`.
-
-   This function should be called before :c:func:`Py_Initialize`, if it is
-   called at all. It specifies which encoding and error handling to use
-   with standard IO, with the same meanings as in :func:`str.encode`.
-
-   It overrides :envvar:`PYTHONIOENCODING` values, and allows embedding code
-   to control IO encoding when the environment variable does not work.
-
-   *encoding* and/or *errors* may be ``NULL`` to use
-   :envvar:`PYTHONIOENCODING` and/or default values (depending on other
-   settings).
-
-   Note that :data:`sys.stderr` always uses the "backslashreplace" error
-   handler, regardless of this (or any other) setting.
-
-   If :c:func:`Py_FinalizeEx` is called, this function will need to be called
-   again in order to affect subsequent calls to :c:func:`Py_Initialize`.
-
-   Returns ``0`` if successful, a nonzero value on error (e.g. calling after the
-   interpreter has already been initialized).
-
-   .. versionadded:: 3.4
-
-   .. deprecated:: 3.11
-
-
-.. c:function:: void Py_SetProgramName(const wchar_t *name)
-
-   .. index::
-      single: Py_Initialize()
-      single: main()
-      single: Py_GetPath()
-
-   This API is kept for backward compatibility: setting
-   :c:member:`PyConfig.program_name` should be used instead, see :ref:`Python
-   Initialization Configuration <init-config>`.
-
-   This function should be called before :c:func:`Py_Initialize` is called for
-   the first time, if it is called at all.  It tells the interpreter the value
-   of the ``argv[0]`` argument to the :c:func:`main` function of the program
-   (converted to wide characters).
-   This is used by :c:func:`Py_GetPath` and some other functions below to find
-   the Python run-time libraries relative to the interpreter executable.  The
-   default value is ``'python'``.  The argument should point to a
-   zero-terminated wide character string in static storage whose contents will not
-   change for the duration of the program's execution.  No code in the Python
-   interpreter will change the contents of this storage.
-
-   Use :c:func:`Py_DecodeLocale` to decode a bytes string to get a
-   :c:expr:`wchar_*` string.
-
-   .. deprecated:: 3.11
-
-
 .. c:function:: wchar* Py_GetProgramName()
 
-   .. index:: single: Py_SetProgramName()
-
-   Return the program name set with :c:func:`Py_SetProgramName`, or the default.
+   Return the program name set with :c:member:`PyConfig.program_name`, or the default.
    The returned string points into static storage; the caller should not modify its
    value.
 
@@ -509,7 +435,7 @@ Process-wide parameters
 
    Return the *prefix* for installed platform-independent files. This is derived
    through a number of complicated rules from the program name set with
-   :c:func:`Py_SetProgramName` and some environment variables; for example, if the
+   :c:member:`PyConfig.program_name` and some environment variables; for example, if the
    program name is ``'/usr/local/bin/python'``, the prefix is ``'/usr/local'``. The
    returned string points into static storage; the caller should not modify its
    value.  This corresponds to the :makevar:`prefix` variable in the top-level
@@ -528,7 +454,7 @@ Process-wide parameters
 
    Return the *exec-prefix* for installed platform-*dependent* files.  This is
    derived through a number of complicated rules from the program name set with
-   :c:func:`Py_SetProgramName` and some environment variables; for example, if the
+   :c:member:`PyConfig.program_name` and some environment variables; for example, if the
    program name is ``'/usr/local/bin/python'``, the exec-prefix is
    ``'/usr/local'``.  The returned string points into static storage; the caller
    should not modify its value.  This corresponds to the :makevar:`exec_prefix`
@@ -568,12 +494,11 @@ Process-wide parameters
 .. c:function:: wchar_t* Py_GetProgramFullPath()
 
    .. index::
-      single: Py_SetProgramName()
       single: executable (in module sys)
 
    Return the full program name of the Python executable; this is  computed as a
    side-effect of deriving the default module search path  from the program name
-   (set by :c:func:`Py_SetProgramName` above). The returned string points into
+   (set by :c:member:`PyConfig.program_name`). The returned string points into
    static storage; the caller should not modify its value.  The value is available
    to Python code as ``sys.executable``.
 
@@ -589,10 +514,9 @@ Process-wide parameters
    .. index::
       triple: module; search; path
       single: path (in module sys)
-      single: Py_SetPath()
 
    Return the default module search path; this is computed from the program name
-   (set by :c:func:`Py_SetProgramName` above) and some environment variables.
+   (set by :c:member:`PyConfig.program_name`) and some environment variables.
    The returned string consists of a series of directory names separated by a
    platform dependent delimiter character.  The delimiter character is ``':'``
    on Unix and macOS, ``';'`` on Windows.  The returned string points into
@@ -610,44 +534,6 @@ Process-wide parameters
       It now returns ``NULL`` if called before :c:func:`Py_Initialize`.
 
 
-.. c:function::  void Py_SetPath(const wchar_t *)
-
-   .. index::
-      triple: module; search; path
-      single: path (in module sys)
-      single: Py_GetPath()
-
-   This API is kept for backward compatibility: setting
-   :c:member:`PyConfig.module_search_paths` and
-   :c:member:`PyConfig.module_search_paths_set` should be used instead, see
-   :ref:`Python Initialization Configuration <init-config>`.
-
-   Set the default module search path.  If this function is called before
-   :c:func:`Py_Initialize`, then :c:func:`Py_GetPath` won't attempt to compute a
-   default search path but uses the one provided instead.  This is useful if
-   Python is embedded by an application that has full knowledge of the location
-   of all modules.  The path components should be separated by the platform
-   dependent delimiter character, which is ``':'`` on Unix and macOS, ``';'``
-   on Windows.
-
-   This also causes :data:`sys.executable` to be set to the program
-   full path (see :c:func:`Py_GetProgramFullPath`) and for :data:`sys.prefix` and
-   :data:`sys.exec_prefix` to be empty.  It is up to the caller to modify these
-   if required after calling :c:func:`Py_Initialize`.
-
-   Use :c:func:`Py_DecodeLocale` to decode a bytes string to get a
-   :c:expr:`wchar_*` string.
-
-   The path argument is copied internally, so the caller may free it after the
-   call completes.
-
-   .. versionchanged:: 3.8
-      The program full path is now used for :data:`sys.executable`, instead
-      of the program name.
-
-   .. deprecated:: 3.11
-
-
 .. c:function:: const char* Py_GetVersion()
 
    Return the version of this Python interpreter.  This is a string that looks
@@ -718,110 +604,10 @@ Process-wide parameters
    ``sys.version``.
 
 
-.. c:function:: void PySys_SetArgvEx(int argc, wchar_t **argv, int updatepath)
-
-   .. index::
-      single: main()
-      single: Py_FatalError()
-      single: argv (in module sys)
-
-   This API is kept for backward compatibility: setting
-   :c:member:`PyConfig.argv`, :c:member:`PyConfig.parse_argv` and
-   :c:member:`PyConfig.safe_path` should be used instead, see :ref:`Python
-   Initialization Configuration <init-config>`.
-
-   Set :data:`sys.argv` based on *argc* and *argv*.  These parameters are
-   similar to those passed to the program's :c:func:`main` function with the
-   difference that the first entry should refer to the script file to be
-   executed rather than the executable hosting the Python interpreter.  If there
-   isn't a script that will be run, the first entry in *argv* can be an empty
-   string.  If this function fails to initialize :data:`sys.argv`, a fatal
-   condition is signalled using :c:func:`Py_FatalError`.
-
-   If *updatepath* is zero, this is all the function does.  If *updatepath*
-   is non-zero, the function also modifies :data:`sys.path` according to the
-   following algorithm:
-
-   - If the name of an existing script is passed in ``argv[0]``, the absolute
-     path of the directory where the script is located is prepended to
-     :data:`sys.path`.
-   - Otherwise (that is, if *argc* is ``0`` or ``argv[0]`` doesn't point
-     to an existing file name), an empty string is prepended to
-     :data:`sys.path`, which is the same as prepending the current working
-     directory (``"."``).
-
-   Use :c:func:`Py_DecodeLocale` to decode a bytes string to get a
-   :c:expr:`wchar_*` string.
-
-   See also :c:member:`PyConfig.orig_argv` and :c:member:`PyConfig.argv`
-   members of the :ref:`Python Initialization Configuration <init-config>`.
-
-   .. note::
-      It is recommended that applications embedding the Python interpreter
-      for purposes other than executing a single script pass ``0`` as *updatepath*,
-      and update :data:`sys.path` themselves if desired.
-      See `CVE-2008-5983 <https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-5983>`_.
-
-      On versions before 3.1.3, you can achieve the same effect by manually
-      popping the first :data:`sys.path` element after having called
-      :c:func:`PySys_SetArgv`, for example using::
-
-         PyRun_SimpleString("import sys; sys.path.pop(0)\n");
-
-   .. versionadded:: 3.1.3
-
-   .. XXX impl. doesn't seem consistent in allowing ``0``/``NULL`` for the params;
-      check w/ Guido.
-
-   .. deprecated:: 3.11
-
-
-.. c:function:: void PySys_SetArgv(int argc, wchar_t **argv)
-
-   This API is kept for backward compatibility: setting
-   :c:member:`PyConfig.argv` and :c:member:`PyConfig.parse_argv` should be used
-   instead, see :ref:`Python Initialization Configuration <init-config>`.
-
-   This function works like :c:func:`PySys_SetArgvEx` with *updatepath* set
-   to ``1`` unless the :program:`python` interpreter was started with the
-   :option:`-I`.
-
-   Use :c:func:`Py_DecodeLocale` to decode a bytes string to get a
-   :c:expr:`wchar_*` string.
-
-   See also :c:member:`PyConfig.orig_argv` and :c:member:`PyConfig.argv`
-   members of the :ref:`Python Initialization Configuration <init-config>`.
-
-   .. versionchanged:: 3.4 The *updatepath* value depends on :option:`-I`.
-
-   .. deprecated:: 3.11
-
-
-.. c:function:: void Py_SetPythonHome(const wchar_t *home)
-
-   This API is kept for backward compatibility: setting
-   :c:member:`PyConfig.home` should be used instead, see :ref:`Python
-   Initialization Configuration <init-config>`.
-
-   Set the default "home" directory, that is, the location of the standard
-   Python libraries.  See :envvar:`PYTHONHOME` for the meaning of the
-   argument string.
-
-   The argument should point to a zero-terminated character string in static
-   storage whose contents will not change for the duration of the program's
-   execution.  No code in the Python interpreter will change the contents of
-   this storage.
-
-   Use :c:func:`Py_DecodeLocale` to decode a bytes string to get a
-   :c:expr:`wchar_*` string.
-
-   .. deprecated:: 3.11
-
-
 .. c:function:: wchar_t* Py_GetPythonHome()
 
-   Return the default "home", that is, the value set by a previous call to
-   :c:func:`Py_SetPythonHome`, or the value of the :envvar:`PYTHONHOME`
+   Return the default "home", that is, the value set by
+   :c:member:`PyConfig.home`, or the value of the :envvar:`PYTHONHOME`
    environment variable if it is set.
 
    This function should not be called before :c:func:`Py_Initialize`, otherwise