gh-107406: Add better struct.Struct repr

[denballakh]

fixes #107406

• Issue: better struct.Struct repr #107406

[cpython-cla-bot]

All commit authors signed the Contributor License Agreement.

[JelleZijlstra]

The code looks right to me and this is definitely an improvement.

Do we need to be concerned about compatibility? I don't think we guarantee backward compatibility for the repr().

[AA-Turner]

Should we document the new Struct.__repr__ method in Doc/library/struct.rst?

A

[JelleZijlstra]

I don't think we need to document the method itself. However, a note in the struct docs with versionchanged 3.13 saying that the repr() is now informative would be good.

[denballakh]

Added note. It now looks like this:

UPD: it looks like this:

[denballakh]

when will it be merged?

[bedevere-bot]

There's a new commit after the PR has been approved.

@kumaraditya303, @JelleZijlstra: please review the changes made to this pull request.

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot ARM Raspbian 3.x has failed when building commit e407cea.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/all/#builders/424/builds/4739) and take a look at the build logs.
4. Check if the failure is related to this commit (e407cea) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/all/#builders/424/builds/4739

Failed tests:

• test.test_concurrent_futures.test_shutdown

Failed subtests:

• test_interpreter_shutdown - test.test_concurrent_futures.test_shutdown.ProcessPoolForkserverProcessPoolShutdownTest.test_interpreter_shutdown

Summary of the results of the build (if available):

== Tests result: FAILURE then FAILURE ==

443 tests OK.

10 slowest tests:

• test_venv: 9 min 9 sec
• test_largefile: 8 min 35 sec
• test_peg_generator: 7 min 32 sec
• test_math: 4 min 32 sec
• test_logging: 4 min 31 sec
• test_hashlib: 2 min 11 sec
• test.test_multiprocessing_spawn.test_processes: 2 min 9 sec
• test_compileall: 2 min 8 sec
• test_codecencodings_cn: 2 min 5 sec
• test_gdb: 1 min 47 sec

1 test failed:
test.test_concurrent_futures.test_shutdown

19 tests skipped:
test.test_asyncio.test_windows_events
test.test_asyncio.test_windows_utils test_devpoll test_idle
test_ioctl test_kqueue test_launcher test_perf_profiler
test_startfile test_tcl test_tkinter test_ttk test_ttk_textonly
test_turtle test_winconsoleio test_winreg test_winsound test_wmi
test_zipfile64

1 re-run test:
test.test_concurrent_futures.test_shutdown

Total duration: 38 min 48 sec

Click to see traceback logs

Traceback (most recent call last):
  File "/var/lib/buildbot/workers/3.x.gps-raspbian.nondebug/build/Lib/test/test_concurrent_futures/test_shutdown.py", line 49, in test_interpreter_shutdown
    self.assertFalse(err)
AssertionError: b'Exception in thread Thread-1:\nTraceback (most recent call last):\n  File "/var/lib/buildbot/workers/3.x.gps-raspbian.nondebug/build/Lib/threading.py", line 1059, in _bootstrap_inner\n    self.run()\n  File "/var/lib/buildbot/workers/3.x.gps-raspbian.nondebug/build/Lib/concurrent/futures/process.py", line 339, in run\n    self.add_call_item_to_queue()\n  File "/var/lib/buildbot/workers/3.x.gps-raspbian.nondebug/build/Lib/concurrent/futures/process.py", line 394, in add_call_item_to_queue\n    self.call_queue.put(_CallItem(work_id,\n  File "/var/lib/buildbot/workers/3.x.gps-raspbian.nondebug/build/Lib/multiprocessing/queues.py", line 94, in put\n    self._start_thread()\n  File "/var/lib/buildbot/workers/3.x.gps-raspbian.nondebug/build/Lib/multiprocessing/queues.py", line 177, in _start_thread\n    self._thread.start()\n  File "/var/lib/buildbot/workers/3.x.gps-raspbian.nondebug/build/Lib/threading.py", line 978, in start\n    _start_new_thread(self._bootstrap, ())\nRuntimeError: can\'t create new thread at interpreter shutdown\nTraceback (most recent call last):\n  File "/var/lib/buildbot/workers/3.x.gps-raspbian.nondebug/build/Lib/multiprocessing/forkserver.py", line 274, in main\n    code = _serve_one(child_r, fds,\n           ^^^^^^^^^^^^^^^^^^^^^^^^\n  File "/var/lib/buildbot/workers/3.x.gps-raspbian.nondebug/build/Lib/multiprocessing/forkserver.py", line 313, in _serve_one\n    code = spawn._main(child_r, parent_sentinel)\n           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File "/var/lib/buildbot/workers/3.x.gps-raspbian.nondebug/build/Lib/multiprocessing/spawn.py", line 132, in _main\n    self = reduction.pickle.load(from_parent)\n           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File "/var/lib/buildbot/workers/3.x.gps-raspbian.nondebug/build/Lib/multiprocessing/synchronize.py", line 115, in __setstate__\n    self._semlock = _multiprocessing.SemLock._rebuild(*state)\n                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\nFileNotFoundError: [Errno 2] No such file or directory\n' is not false