gh-104773: PEP 594: Remove the sndhdr module

[vstinner]

Remove the Lib/test/sndhdrdata/ directory.

• Issue: PEP 594: Remove stdlib modules scheduled for deletion in Python 3.13 #104773

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📚 Documentation preview 📚: https://cpython-previews--104774.org.readthedocs.build/

[vstinner]

I ignored mentions of the sndhdr module in comments of the email module, Lib/email/mime/audio.py:

# Originally from the sndhdr module.## There are others in sndhdr that don't have MIME types. :(# Additional ones to be added to sndhdr? midi, mp3, realaudio, wma??def_what(data):
# Try to identify a sound file type.## sndhdr.what() had a pretty cruddy interface, unfortunately. This is why# we re-do it here. It would be easier to reverse engineer the Unix 'file'# command and use the standard 'magic' file, as shipped with a modern Unix.hdr=data[:512]
fakefile=BytesIO(hdr)
fortestfnin_rules:
ifres:=testfn(hdr, fakefile):
returnreselse:
returnNone

[vstinner]

Fix the Docs CI: Warning: (...)/Doc/whatsnew/3.12.rst:819: WARNING: py:mod reference target not found: sndhdr.

[hugovk]

Please could you also update the refs in 3.11.rst?

For example with an exclamation mark:

* :pep:`594` led to the deprecations of the following modules
slated for removal in Python 3.13:
+---------------------+---------------------+---------------------+---------------------+---------------------+ |:mod:`aifc` |:mod:`chunk` |:mod:`msilib` |:mod:`pipes` |:mod:`telnetlib` |+---------------------+---------------------+---------------------+---------------------+---------------------+ |:mod:`audioop` |:mod:`crypt` |:mod:`nis` |:mod:`!sndhdr` |:mod:`uu` |+---------------------+---------------------+---------------------+---------------------+---------------------+ |:mod:`cgi` |:mod:`imghdr` |:mod:`nntplib` |:mod:`spwd` |:mod:`xdrlib` |+---------------------+---------------------+---------------------+---------------------+---------------------+ |:mod:`cgitb` |:mod:`mailcap` |:mod:`ossaudiodev` |:mod:`sunau` ||+---------------------+---------------------+---------------------+---------------------+---------------------+

You could do them all in a single commit/PR, to avoid lots of conflicts later.

And:

diff --git a/Doc/whatsnew/3.5.rst b/Doc/whatsnew/3.5.rst
index 14b6425cea..a1b6e18950 100644
--- a/Doc/whatsnew/3.5.rst+++ b/Doc/whatsnew/3.5.rst@@ -1714,7 +1714,7 @@ support :rfc:`6531` (SMTPUTF8).
sndhdr
------
-The :func:`~sndhdr.what` and :func:`~sndhdr.whathdr` functions now return+The ``what`` and ``whathdr`` functions now return
a :func:`~collections.namedtuple`. (Contributed by Claudiu Popa in
:issue:`18615`.)

[vstinner]

I updated the doc: I added PEP 594 and replaced sndhdr with !sndhdr. I also rebased the PR on the main to retrieve recent test fixes (especially test_importlib).