permutation implementation of WeylGroup fails in A_0

[Etn40ff]

Steps To Reproduce

This works as expected:

[ins] In [1]: W = WeylGroup(['A',0])
[ins] In [2]: W[0]
Out[2]: [1]

While this coredumps:

[ins] In [3]: W = WeylGroup(['A',0], implementation='permutation')
[ins] In [4]: W[0]
------------------------------------------------------------------------
/usr/lib/python3.12/site-packages/cysignals/signals.cpython-312-x86_64-linux-gnu.so(+0xa004)[0x7f7997fda004]
/usr/lib/python3.12/site-packages/cysignals/signals.cpython-312-x86_64-linux-gnu.so(+0xa0cf)[0x7f7997fda0cf]
/usr/lib/python3.12/site-packages/cysignals/signals.cpython-312-x86_64-linux-gnu.so(+0xca96)[0x7f7997fdca96]
/usr/lib64/libc.so.6(+0x3c3b0)[0x7f799825c3b0]
/usr/lib/python3.12/site-packages/sage/combinat/root_system/reflection_group_c.cpython-312-x86_64-linux-gnu.so(+0x1553e)[0x7f79407f753e]
/usr/lib/python3.12/site-packages/sage/structure/category_object.cpython-312-x86_64-linux-gnu.so(+0x987c)[0x7f79969cc87c]
/usr/lib64/libpython3.12.so.1.0(+0xf0a23)[0x7f79984f0a23]
/usr/lib64/libpython3.12.so.1.0(_PyEval_EvalFrameDefault+0x36f0)[0x7f799848c520]
/usr/lib/python3.12/site-packages/sage/structure/parent.cpython-312-x86_64-linux-gnu.so(+0x36abb)[0x7f7996723abb]
/usr/lib64/libpython3.12.so.1.0(_PyEval_EvalFrameDefault+0x8016)[0x7f7998490e46]
/usr/lib64/libpython3.12.so.1.0(PyEval_EvalCode+0xbe)[0x7f79985cfa5e]
/usr/lib64/libpython3.12.so.1.0(+0x1cbda0)[0x7f79985cbda0]
/usr/lib64/libpython3.12.so.1.0(_PyEval_EvalFrameDefault+0x4276)[0x7f799848d0a6]
/usr/lib64/libpython3.12.so.1.0(+0xf97ad)[0x7f79984f97ad]
/usr/lib64/libpython3.12.so.1.0(+0xfaa87)[0x7f79984faa87]
/usr/lib64/libpython3.12.so.1.0(_PyEval_EvalFrameDefault+0x4ba6)[0x7f799848d9d6]
/usr/lib64/libpython3.12.so.1.0(PyEval_EvalCode+0xbe)[0x7f79985cfa5e]
/usr/lib64/libpython3.12.so.1.0(+0x221426)[0x7f7998621426]
/usr/lib64/libpython3.12.so.1.0(+0x221539)[0x7f7998621539]
/usr/lib64/libpython3.12.so.1.0(+0x221630)[0x7f7998621630]
/usr/lib64/libpython3.12.so.1.0(_PyRun_SimpleFileObject+0x12d)[0x7f799862449d]
/usr/lib64/libpython3.12.so.1.0(_PyRun_AnyFileObject+0x40)[0x7f7998624b40]
/usr/lib64/libpython3.12.so.1.0(Py_RunMain+0xa04)[0x7f7998648b54]
/usr/lib64/libpython3.12.so.1.0(Py_BytesMain+0x5b)[0x7f799864909b]
/usr/lib64/libc.so.6(+0x26350)[0x7f7998246350]
/usr/lib64/libc.so.6(__libc_start_main+0x89)[0x7f7998246409]
/usr/bin/python3.12(_start+0x25)[0x5603ac81b095]
------------------------------------------------------------------------
Attaching gdb to process id 15183.
/usr/lib/python-exec/python3.12/cysignals-CSI:88: DeprecationWarning: Use shutil.which instead of find_executable
  whichgdb = find_executable('gdb')
GNU gdb (Gentoo 14.2 vanilla) 14.2
Copyright (C) 2023 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "x86_64-pc-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<https://bugs.gentoo.org/>.
Find the GDB manual and other documentation resources online at:
    <http://www.gnu.org/software/gdb/documentation/>.

For help, type "help".
Type "apropos word" to search for commands related to "word".
[New LWP 15206]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/lib64/libthread_db.so.1".
0x00007f79983107e7 in wait4 () from /usr/lib64/libc.so.6

Stack backtrace
---------------
No symbol table info available.
#1  0x00007f7997fda136 in ?? ()
   from /usr/lib/python3.12/site-packages/cysignals/signals.cpython-312-x86_64-linux-gnu.so
No symbol table info available.
#2  0x00007f7997fdca96 in ?? ()
   from /usr/lib/python3.12/site-packages/cysignals/signals.cpython-312-x86_64-linux-gnu.so
No symbol table info available.
#3  <signal handler called>
No symbol table info available.
#4  0x00007f79407f753e in ?? ()
   from /usr/lib/python3.12/site-packages/sage/combinat/root_system/reflection_group_c.cpython-312-x86_64-linux-gnu.so
No symbol table info available.
#5  0x00007f79969cc87c in ?? ()
   from /usr/lib/python3.12/site-packages/sage/structure/category_object.cpython-312-x86_64-linux-gnu.so
No symbol table info available.
#6  0x00007f79984f0a23 in ?? () from /usr/lib64/libpython3.12.so.1.0
No symbol table info available.
#7  0x00007f799848c520 in _PyEval_EvalFrameDefault ()
   from /usr/lib64/libpython3.12.so.1.0
No symbol table info available.
#8  0x00007f7996723abb in ?? ()
   from /usr/lib/python3.12/site-packages/sage/structure/parent.cpython-312-x86_64-linux-gnu.so
No symbol table info available.
#9  0x00007f7998490e46 in _PyEval_EvalFrameDefault ()
   from /usr/lib64/libpython3.12.so.1.0
No symbol table info available.
#10 0x00007f79985cfa5e in PyEval_EvalCode ()
   from /usr/lib64/libpython3.12.so.1.0
No symbol table info available.
#11 0x00007f79985cbda0 in ?? () from /usr/lib64/libpython3.12.so.1.0
No symbol table info available.
#12 0x00007f799848d0a6 in _PyEval_EvalFrameDefault ()
   from /usr/lib64/libpython3.12.so.1.0
No symbol table info available.
#13 0x00007f79984f97ad in ?? () from /usr/lib64/libpython3.12.so.1.0
No symbol table info available.
#14 0x00007f79984faa87 in ?? () from /usr/lib64/libpython3.12.so.1.0
No symbol table info available.
#15 0x00007f799848d9d6 in _PyEval_EvalFrameDefault ()
   from /usr/lib64/libpython3.12.so.1.0
No symbol table info available.
#16 0x00007f79985cfa5e in PyEval_EvalCode ()
   from /usr/lib64/libpython3.12.so.1.0
No symbol table info available.
#17 0x00007f7998621426 in ?? () from /usr/lib64/libpython3.12.so.1.0
No symbol table info available.
#18 0x00007f7998621539 in ?? () from /usr/lib64/libpython3.12.so.1.0
No symbol table info available.
#19 0x00007f7998621630 in ?? () from /usr/lib64/libpython3.12.so.1.0
No symbol table info available.
#20 0x00007f799862449d in _PyRun_SimpleFileObject ()
   from /usr/lib64/libpython3.12.so.1.0
No symbol table info available.
#21 0x00007f7998624b40 in _PyRun_AnyFileObject ()
   from /usr/lib64/libpython3.12.so.1.0
No symbol table info available.
#22 0x00007f7998648b54 in Py_RunMain () from /usr/lib64/libpython3.12.so.1.0
No symbol table info available.
#23 0x00007f799864909b in Py_BytesMain () from /usr/lib64/libpython3.12.so.1.0
No symbol table info available.
#24 0x00007f7998246350 in ?? () from /usr/lib64/libc.so.6
No symbol table info available.
#25 0x00007f7998246409 in __libc_start_main () from /usr/lib64/libc.so.6
No symbol table info available.
#26 0x00005603ac81b095 in _start ()
No symbol table info available.


Cython backtrace
----------------
#0  0x00007f7998310790 in wait4 ()
#1  0x0000000000000000 in ?? ()
#2  0x0000000000000000 in ?? ()
#3  0x0000000000000000 in ?? ()
#4  0x0000000000000000 in ?? ()
#5  0x0000000000000000 in ?? ()
#6  0x0000000000000000 in ?? ()
#7  0x00007f7998488e30 in _PyEval_EvalFrameDefault ()
#8  0x0000000000000000 in ?? ()
#9  0x00007f7998488e30 in _PyEval_EvalFrameDefault ()
#10 0x00007f79985cf9a0 in PyEval_EvalCode ()
#11 0x0000000000000000 in ?? ()
#12 0x00007f7998488e30 in _PyEval_EvalFrameDefault ()
#13 0x0000000000000000 in ?? ()
#14 0x0000000000000000 in ?? ()
#15 0x00007f7998488e30 in _PyEval_EvalFrameDefault ()
#16 0x00007f79985cf9a0 in PyEval_EvalCode ()
#17 0x0000000000000000 in ?? ()
#18 0x0000000000000000 in ?? ()
#19 0x0000000000000000 in ?? ()
#20 0x00007f7998624370 in _PyRun_SimpleFileObject ()
#21 0x00007f7998624b00 in _PyRun_AnyFileObject ()
#22 0x00007f7998648150 in Py_RunMain ()
#23 0x00007f7998649040 in Py_BytesMain ()
#24 0x0000000000000000 in ?? ()
#25 0x00007f7998246380 in __libc_start_main ()
#26 0x00005603ac81b070 in _start ()

[Inferior 1 (process 15183) detached]
/usr/lib/python-exec/python3.12/cysignals-CSI:137: DeprecationWarning: datetime.datetime.utcfromtimestamp() is deprecated and scheduled for removal in a future version. Use timezone-aware objects to represent datetimes in UTC: datetime.datetime.fromtimestamp(timestamp, datetime.UTC).
  mtime = datetime.utcfromtimestamp(os.path.getmtime(filename))
/usr/lib/python-exec/python3.12/cysignals-CSI:138: DeprecationWarning: datetime.datetime.utcnow() is deprecated and scheduled for removal in a future version. Use timezone-aware objects to represent datetimes in UTC: datetime.datetime.now(datetime.UTC).
  age = datetime.utcnow() - mtime
Saved trace to /home/VulK/cysignals_crash_logs/crash_lfjls5ct.log
------------------------------------------------------------------------
Unhandled SIGSEGV: A segmentation fault occurred.
This probably occurred because a *compiled* module has a bug
in it and is not properly wrapped with sig_on(), sig_off().
Python will now terminate.
------------------------------------------------------------------------
[1]    15183 segmentation fault (core dumped)  sage

Expected Behavior

Return the unique element in W

Actual Behavior

Crash

Additional Information

No response

Environment

• OS: gentoo
• Sage Version: 10.4 installed via sage-on-gentoo
• Python version: 3.12.6

Checklist

• I have searched the existing issues for a bug report that matches the one I want to file, without success.
• I have read the documentation and troubleshoot guide

[fchapoton]

Hello Salvatore ! would you please review the fix ?

[Etn40ff]

I Frederic, I'll be glad to. The code looks goot to me.

I never contrubuted anything to sage after the switch to GH, I am not even sure I have the right permissions to make reviews; can you please point me to some documentation or a checklist about the process?

[fchapoton]

Well, there is the general document

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/about-pull-request-reviews

Concerning your rights, I have just invited you to the "triage" team, that allows to work smoothly.

[Etn40ff]

#38702 fixes this