[3.9] bpo-40204: Allow pre-Sphinx 3 syntax in the doc (GH-21844) (GH-21901)

* bpo-40204: Allow pre-Sphinx 3 syntax in the doc (GH-21844)

Enable Sphinx 3.2 "c_allow_pre_v3" option and disable the
c_warn_on_allowed_pre_v3 option to make the documentation compatible
with Sphinx 2 and Sphinx 3.

(cherry picked from commit 423e77d)

* bpo-40204: Fix Sphinx sytanx in howto/instrumentation.rst (GH-21858)

Use generic '.. object::' to declare markers, rather than abusing
'..  c:function::' which fails on Sphinx 3.

(cherry picked from commit 43577c0)

* bpo-40204: Fix duplicates in the documentation (GH-21857)

Fix two Sphinx 3 issues:

Doc/c-api/buffer.rst:304: WARNING: Duplicate C declaration, also defined in 'c-api/buffer'.
Declaration is 'PyBUF_ND'.

Doc/c-api/unicode.rst:1603: WARNING: Duplicate C declaration, also defined in 'c-api/unicode'.
Declaration is 'PyObject* PyUnicode_Translate(PyObject *str, PyObject *table, const char *errors)'.

(cherry picked from commit 46d10b1)

* bpo-40204: Add :noindex: in the documentation (GH-21859)

Add :noindex: to duplicated documentation to fix "duplicate object
description" errors.

For example, fix this Sphinx 3 issue:

Doc/library/configparser.rst:1146: WARNING: duplicate object
description of configparser.ConfigParser.optionxform, other instance
in library/configparser, use :noindex: for one of them

(cherry picked from commit d3ded08)

* bpo-40204, doc: Fix syntax of C variables (GH-21846)

For example, fix the following Sphinx 3 errors:

Doc/c-api/buffer.rst:102: WARNING: Error in declarator or parameters
Invalid C declaration: Expected identifier in nested name. [error at 5]
  void \*obj
  -----^

Doc/c-api/arg.rst:130: WARNING: Unparseable C cross-reference: 'PyObject*'
Invalid C declaration: Expected end of definition. [error at 8]
  PyObject*
  --------^

The modified documentation is compatible with Sphinx 2 and Sphinx 3.

(cherry picked from commit 474652f)

* bpo-40204: Fix reference to terms in the doc (GH-21865)

Sphinx 3 requires to refer to terms with the exact case.

For example, fix the Sphinx 3 warning:

Doc/library/pkgutil.rst:71: WARNING: term Loader not found in case
sensitive match.made a reference to loader instead.

(cherry picked from commit bb0b085)

* bpo-40204: Fix duplicated productionlist names in the doc (GH-21900)

Sphinx 3 disallows having more than one productionlist markup with
the same name. Simply remove names in this case, since names are not
shown anyway. For example, fix the Sphinx 3 warning:

Doc/reference/introduction.rst:96: duplicate token description
of *:name, other instance in reference/expressions

(cherry picked from commit 1abeda8)

Author: vstinner

Doc/c-api/arg.rst

@@ -131,12 +131,12 @@ which disallows mutable objects such as :class:`bytearray`.
 ``S`` (:class:`bytes`) [PyBytesObject \*]
    Requires that the Python object is a :class:`bytes` object, without
    attempting any conversion.  Raises :exc:`TypeError` if the object is not
-   a bytes object.  The C variable may also be declared as :c:type:`PyObject\*`.
+   a bytes object.  The C variable may also be declared as :c:type:`PyObject*`.
 
 ``Y`` (:class:`bytearray`) [PyByteArrayObject \*]
    Requires that the Python object is a :class:`bytearray` object, without
    attempting any conversion.  Raises :exc:`TypeError` if the object is not
-   a :class:`bytearray` object. The C variable may also be declared as :c:type:`PyObject\*`.
+   a :class:`bytearray` object. The C variable may also be declared as :c:type:`PyObject*`.
 
 ``u`` (:class:`str`) [const Py_UNICODE \*]
    Convert a Python Unicode object to a C pointer to a NUL-terminated buffer of
@@ -183,7 +183,7 @@ which disallows mutable objects such as :class:`bytearray`.
 ``U`` (:class:`str`) [PyObject \*]
    Requires that the Python object is a Unicode object, without attempting
    any conversion.  Raises :exc:`TypeError` if the object is not a Unicode
-   object.  The C variable may also be declared as :c:type:`PyObject\*`.
+   object.  The C variable may also be declared as :c:type:`PyObject*`.
 
 ``w*`` (read-write :term:`bytes-like object`) [Py_buffer]
    This format accepts any object which implements the read-write buffer
@@ -196,10 +196,10 @@ which disallows mutable objects such as :class:`bytearray`.
    It only works for encoded data without embedded NUL bytes.
 
    This format requires two arguments.  The first is only used as input, and
-   must be a :c:type:`const char\*` which points to the name of an encoding as a
+   must be a :c:type:`const char*` which points to the name of an encoding as a
    NUL-terminated string, or ``NULL``, in which case ``'utf-8'`` encoding is used.
    An exception is raised if the named encoding is not known to Python.  The
-   second argument must be a :c:type:`char\*\*`; the value of the pointer it
+   second argument must be a :c:type:`char**`; the value of the pointer it
    references will be set to a buffer with the contents of the argument text.
    The text will be encoded in the encoding specified by the first argument.
 
@@ -219,10 +219,10 @@ which disallows mutable objects such as :class:`bytearray`.
    characters.
 
    It requires three arguments.  The first is only used as input, and must be a
-   :c:type:`const char\*` which points to the name of an encoding as a
+   :c:type:`const char*` which points to the name of an encoding as a
    NUL-terminated string, or ``NULL``, in which case ``'utf-8'`` encoding is used.
    An exception is raised if the named encoding is not known to Python.  The
-   second argument must be a :c:type:`char\*\*`; the value of the pointer it
+   second argument must be a :c:type:`char**`; the value of the pointer it
    references will be set to a buffer with the contents of the argument text.
    The text will be encoded in the encoding specified by the first argument.
    The third argument must be a pointer to an integer; the referenced integer
@@ -322,7 +322,7 @@ Other objects
 ``O!`` (object) [*typeobject*, PyObject \*]
    Store a Python object in a C object pointer.  This is similar to ``O``, but
    takes two C arguments: the first is the address of a Python type object, the
-   second is the address of the C variable (of type :c:type:`PyObject\*`) into which
+   second is the address of the C variable (of type :c:type:`PyObject*`) into which
    the object pointer is stored.  If the Python object does not have the required
    type, :exc:`TypeError` is raised.
 
@@ -331,13 +331,13 @@ Other objects
 ``O&`` (object) [*converter*, *anything*]
    Convert a Python object to a C variable through a *converter* function.  This
    takes two arguments: the first is a function, the second is the address of a C
-   variable (of arbitrary type), converted to :c:type:`void \*`.  The *converter*
+   variable (of arbitrary type), converted to :c:type:`void *`.  The *converter*
    function in turn is called as follows::
 
       status = converter(object, address);
 
    where *object* is the Python object to be converted and *address* is the
-   :c:type:`void\*` argument that was passed to the :c:func:`PyArg_Parse\*` function.
+   :c:type:`void*` argument that was passed to the :c:func:`PyArg_Parse\*` function.
    The returned *status* should be ``1`` for a successful conversion and ``0`` if
    the conversion has failed.  When the conversion fails, the *converter* function
    should raise an exception and leave the content of *address* unmodified.
@@ -483,7 +483,7 @@ API Functions
    *args*; it must actually be a tuple.  The length of the tuple must be at least
    *min* and no more than *max*; *min* and *max* may be equal.  Additional
    arguments must be passed to the function, each of which should be a pointer to a
-   :c:type:`PyObject\*` variable; these will be filled in with the values from
+   :c:type:`PyObject*` variable; these will be filled in with the values from
    *args*; they will contain borrowed references.  The variables which correspond
    to optional parameters not given by *args* will not be filled in; these should
    be initialized by the caller. This function returns true on success and false if
@@ -652,8 +652,8 @@ Building values
 
    ``O&`` (object) [*converter*, *anything*]
       Convert *anything* to a Python object through a *converter* function.  The
-      function is called with *anything* (which should be compatible with :c:type:`void
-      \*`) as its argument and should return a "new" Python object, or ``NULL`` if an
+      function is called with *anything* (which should be compatible with :c:type:`void*`)
+      as its argument and should return a "new" Python object, or ``NULL`` if an
       error occurred.
 
    ``(items)`` (:class:`tuple`) [*matching-items*]

Doc/c-api/buffer.rst

@@ -89,7 +89,7 @@ a buffer, see :c:func:`PyObject_GetBuffer`.
 
 .. c:type:: Py_buffer
 
-   .. c:member:: void \*buf
+   .. c:member:: void *buf
 
       A pointer to the start of the logical structure described by the buffer
       fields. This can be any location within the underlying physical memory
@@ -99,7 +99,7 @@ a buffer, see :c:func:`PyObject_GetBuffer`.
       For :term:`contiguous` arrays, the value points to the beginning of
       the memory block.
 
-   .. c:member:: void \*obj
+   .. c:member:: void *obj
 
       A new reference to the exporting object. The reference is owned by
       the consumer and automatically decremented and set to ``NULL`` by
@@ -145,7 +145,7 @@ a buffer, see :c:func:`PyObject_GetBuffer`.
       or a :c:macro:`PyBUF_WRITABLE` request, the consumer must disregard
       :c:member:`~Py_buffer.itemsize` and assume ``itemsize == 1``.
 
-   .. c:member:: const char \*format
+   .. c:member:: const char *format
 
       A *NUL* terminated string in :mod:`struct` module style syntax describing
       the contents of a single item. If this is ``NULL``, ``"B"`` (unsigned bytes)
@@ -164,7 +164,7 @@ a buffer, see :c:func:`PyObject_GetBuffer`.
       to 64. Exporters MUST respect this limit, consumers of multi-dimensional
       buffers SHOULD be able to handle up to :c:macro:`PyBUF_MAX_NDIM` dimensions.
 
-   .. c:member:: Py_ssize_t \*shape
+   .. c:member:: Py_ssize_t *shape
 
       An array of :c:type:`Py_ssize_t` of length :c:member:`~Py_buffer.ndim`
       indicating the shape of the memory as an n-dimensional array. Note that
@@ -177,7 +177,7 @@ a buffer, see :c:func:`PyObject_GetBuffer`.
 
       The shape array is read-only for the consumer.
 
-   .. c:member:: Py_ssize_t \*strides
+   .. c:member:: Py_ssize_t *strides
 
       An array of :c:type:`Py_ssize_t` of length :c:member:`~Py_buffer.ndim`
       giving the number of bytes to skip to get to a new element in each
@@ -189,7 +189,7 @@ a buffer, see :c:func:`PyObject_GetBuffer`.
 
       The strides array is read-only for the consumer.
 
-   .. c:member:: Py_ssize_t \*suboffsets
+   .. c:member:: Py_ssize_t *suboffsets
 
       An array of :c:type:`Py_ssize_t` of length :c:member:`~Py_buffer.ndim`.
       If ``suboffsets[n] >= 0``, the values stored along the nth dimension are
@@ -207,7 +207,7 @@ a buffer, see :c:func:`PyObject_GetBuffer`.
 
       The suboffsets array is read-only for the consumer.
 
-   .. c:member:: void \*internal
+   .. c:member:: void *internal
 
       This is for use internally by the exporting object. For example, this
       might be re-cast as an integer by the exporter and used to store flags
@@ -301,7 +301,7 @@ must be C-contiguous.
 +-----------------------------------+-------+---------+------------+--------+
 | .. c:macro:: PyBUF_ANY_CONTIGUOUS |  yes  |   yes   |    NULL    | C or F |
 +-----------------------------------+-------+---------+------------+--------+
-| .. c:macro:: PyBUF_ND             |  yes  |   NULL  |    NULL    |   C    |
+| :c:macro:`PyBUF_ND`               |  yes  |   NULL  |    NULL    |   C    |
 +-----------------------------------+-------+---------+------------+--------+
 
 
@@ -438,12 +438,12 @@ Buffer-related functions
 
    Send a request to *exporter* to fill in *view* as specified by  *flags*.
    If the exporter cannot provide a buffer of the exact type, it MUST raise
-   :c:data:`PyExc_BufferError`, set :c:member:`view->obj` to ``NULL`` and
+   :c:data:`PyExc_BufferError`, set ``view->obj`` to ``NULL`` and
    return ``-1``.
 
-   On success, fill in *view*, set :c:member:`view->obj` to a new reference
+   On success, fill in *view*, set ``view->obj`` to a new reference
    to *exporter* and return 0. In the case of chained buffer providers
-   that redirect requests to a single object, :c:member:`view->obj` MAY
+   that redirect requests to a single object, ``view->obj`` MAY
    refer to this object instead of *exporter* (See :ref:`Buffer Object Structures <buffer-structs>`).
 
    Successful calls to :c:func:`PyObject_GetBuffer` must be paired with calls
@@ -455,7 +455,7 @@ Buffer-related functions
 .. c:function:: void PyBuffer_Release(Py_buffer *view)
 
    Release the buffer *view* and decrement the reference count for
-   :c:member:`view->obj`. This function MUST be called when the buffer
+   ``view->obj``. This function MUST be called when the buffer
    is no longer being used, otherwise reference leaks may occur.
 
    It is an error to call this function on a buffer that was not obtained via
@@ -516,9 +516,9 @@ Buffer-related functions
    *view* as specified by flags, unless *buf* has been designated as read-only
    and :c:macro:`PyBUF_WRITABLE` is set in *flags*.
 
-   On success, set :c:member:`view->obj` to a new reference to *exporter* and
+   On success, set ``view->obj`` to a new reference to *exporter* and
    return 0. Otherwise, raise :c:data:`PyExc_BufferError`, set
-   :c:member:`view->obj` to ``NULL`` and return ``-1``;
+   ``view->obj`` to ``NULL`` and return ``-1``;
 
    If this function is used as part of a :ref:`getbufferproc <buffer-structs>`,
    *exporter* MUST be set to the exporting object and *flags* must be passed

Doc/c-api/call.rst

@@ -84,7 +84,7 @@ This is a pointer to a function with the following signature:
    and they must be unique.
    If there are no keyword arguments, then *kwnames* can instead be *NULL*.
 
-.. c:var:: PY_VECTORCALL_ARGUMENTS_OFFSET
+.. c:macro:: PY_VECTORCALL_ARGUMENTS_OFFSET
 
    If this flag is set in a vectorcall *nargsf* argument, the callee is allowed
    to temporarily change ``args[-1]``. In other words, *args* points to
@@ -283,7 +283,7 @@ please see individual documentation for details.
 
    This is the equivalent of the Python expression: ``callable(*args)``.
 
-   Note that if you only pass :c:type:`PyObject \*` args,
+   Note that if you only pass :c:type:`PyObject *` args,
    :c:func:`PyObject_CallFunctionObjArgs` is a faster alternative.
 
    .. versionchanged:: 3.4
@@ -304,17 +304,17 @@ please see individual documentation for details.
    This is the equivalent of the Python expression:
    ``obj.name(arg1, arg2, ...)``.
 
-   Note that if you only pass :c:type:`PyObject \*` args,
+   Note that if you only pass :c:type:`PyObject *` args,
    :c:func:`PyObject_CallMethodObjArgs` is a faster alternative.
 
    .. versionchanged:: 3.4
       The types of *name* and *format* were changed from ``char *``.
 
 
-.. c:function:: PyObject* PyObject_CallFunctionObjArgs(PyObject *callable, ..., NULL)
+.. c:function:: PyObject* PyObject_CallFunctionObjArgs(PyObject *callable, ...)
 
    Call a callable Python object *callable*, with a variable number of
-   :c:type:`PyObject \*` arguments.  The arguments are provided as a variable number
+   :c:type:`PyObject *` arguments.  The arguments are provided as a variable number
    of parameters followed by *NULL*.
 
    Return the result of the call on success, or raise an exception and return
@@ -324,11 +324,11 @@ please see individual documentation for details.
    ``callable(arg1, arg2, ...)``.
 
 
-.. c:function:: PyObject* PyObject_CallMethodObjArgs(PyObject *obj, PyObject *name, ..., NULL)
+.. c:function:: PyObject* PyObject_CallMethodObjArgs(PyObject *obj, PyObject *name, ...)
 
    Call a method of the Python object *obj*, where the name of the method is given as a
    Python string object in *name*.  It is called with a variable number of
-   :c:type:`PyObject \*` arguments.  The arguments are provided as a variable number
+   :c:type:`PyObject *` arguments.  The arguments are provided as a variable number
    of parameters followed by *NULL*.
 
    Return the result of the call on success, or raise an exception and return

Doc/c-api/capsule.rst

@@ -15,7 +15,7 @@ Refer to :ref:`using-capsules` for more information on using these objects.
 .. c:type:: PyCapsule
 
    This subtype of :c:type:`PyObject` represents an opaque value, useful for C
-   extension modules who need to pass an opaque value (as a :c:type:`void\*`
+   extension modules who need to pass an opaque value (as a :c:type:`void*`
    pointer) through Python code to other C code.  It is often used to make a C
    function pointer defined in one module available to other modules, so the
    regular import mechanism can be used to access C APIs defined in dynamically

Doc/c-api/dict.rst

@@ -73,7 +73,7 @@ Dictionary Objects
    .. index:: single: PyUnicode_FromString()
 
    Insert *val* into the dictionary *p* using *key* as a key. *key* should
-   be a :c:type:`const char\*`.  The key object is created using
+   be a :c:type:`const char*`.  The key object is created using
    ``PyUnicode_FromString(key)``.  Return ``0`` on success or ``-1`` on
    failure.  This function *does not* steal a reference to *val*.
 
@@ -112,7 +112,7 @@ Dictionary Objects
 .. c:function:: PyObject* PyDict_GetItemString(PyObject *p, const char *key)
 
    This is the same as :c:func:`PyDict_GetItem`, but *key* is specified as a
-   :c:type:`const char\*`, rather than a :c:type:`PyObject\*`.
+   :c:type:`const char*`, rather than a :c:type:`PyObject*`.
 
    Note that exceptions which occur while calling :meth:`__hash__` and
    :meth:`__eq__` methods and creating a temporary string object
@@ -161,7 +161,7 @@ Dictionary Objects
    prior to the first call to this function to start the iteration; the
    function returns true for each pair in the dictionary, and false once all
    pairs have been reported.  The parameters *pkey* and *pvalue* should either
-   point to :c:type:`PyObject\*` variables that will be filled in with each key
+   point to :c:type:`PyObject*` variables that will be filled in with each key
    and value, respectively, or may be ``NULL``.  Any references returned through
    them are borrowed.  *ppos* should not be altered during iteration. Its
    value represents offsets within the internal dictionary structure, and

Doc/c-api/exceptions.rst

@@ -783,7 +783,7 @@ Standard Exceptions
 
 All standard Python exceptions are available as global variables whose names are
 ``PyExc_`` followed by the Python exception name.  These have the type
-:c:type:`PyObject\*`; they are all class objects.  For completeness, here are all
+:c:type:`PyObject*`; they are all class objects.  For completeness, here are all
 the variables:
 
 .. index::
@@ -1003,7 +1003,7 @@ Standard Warning Categories
 
 All standard Python warning categories are available as global variables whose
 names are ``PyExc_`` followed by the Python exception name. These have the type
-:c:type:`PyObject\*`; they are all class objects. For completeness, here are all
+:c:type:`PyObject*`; they are all class objects. For completeness, here are all
 the variables:
 
 .. index::

Doc/c-api/file.rst

@@ -8,7 +8,7 @@ File Objects
 .. index:: object: file
 
 These APIs are a minimal emulation of the Python 2 C API for built-in file
-objects, which used to rely on the buffered I/O (:c:type:`FILE\*`) support
+objects, which used to rely on the buffered I/O (:c:type:`FILE*`) support
 from the C standard library.  In Python 3, files and streams use the new
 :mod:`io` module, which defines several layers over the low-level unbuffered
 I/O of the operating system.  The functions described below are
@@ -17,7 +17,7 @@ error reporting in the interpreter; third-party code is advised to access
 the :mod:`io` APIs instead.
 
 
-.. c:function:: PyFile_FromFd(int fd, const char *name, const char *mode, int buffering, const char *encoding, const char *errors, const char *newline, int closefd)
+.. c:function:: PyObject* PyFile_FromFd(int fd, const char *name, const char *mode, int buffering, const char *encoding, const char *errors, const char *newline, int closefd)
 
    Create a Python file object from the file descriptor of an already
    opened file *fd*.  The arguments *name*, *encoding*, *errors* and *newline*