Adapt to deprecation of seeding based on hashing in Python 3.9

[slel]

Python 3.9 deprecates seeding based on hashing.

• https://docs.python.org/3.9/library/random.html#random.seed

  Deprecated since version 3.9: In the future, the seed must be
  one of the following types: NoneType, int, float, str, bytes,
  or bytearray.

This causes a doctest failure in Sage 9.2.rc0 using Python 3.9:

sage -t --long --random-seed=0 src/sage/rings/polynomial/pbori/randompoly.py
**********************************************************************
File "src/sage/rings/polynomial/pbori/randompoly.py", line 46, in sage.rings.polynomial.pbori.randompoly.?
Failed example:
    s=sparse_random_system(r, number_of_polynomials = 20, variables_per_polynomial = 3, degree=2, random_seed=123)
    DeprecationWarning: Seeding based on hashing is deprecated
    since Python 3.9 and will be removed in a subsequent version. The only 
    supported seed types are: None, int, float, str, bytes, and bytearray.

First discussed at #30184 (comments 25, 33, 40, 55).

CC: @kiwifb @mkoeppe @slel

Component: refactoring

Keywords: seed, hash, pbori, polybori, randompoly, deprecation

Author: Frédéric Chapoton

Branch/Commit: de815db

Reviewer: Dima Pasechnik

Issue created by migration from https://trac.sagemath.org/ticket/30765

[slel]

comment:1

Possible workaround: silence the deprecation warning for now,
as we did in other cases.

See for instance:

• Restore deprecation warnings for imports from collections vs collections.abc #30768: Restore deprecation warnings for imports from collections vs collections.abc

[fchapoton]

Commit: c53d261

[fchapoton]

Author: Frédéric Chapoton

[fchapoton]

Branch: u/chapoton/30765

[fchapoton]

comment:3

I have made some general cleanup of pbori/

I have forced the seeds to be int. Would you please tell me if this removes the warning ?

---

New commits:

c53d261

some cleanup in pbori

[dimpase]

comment:5

this does work with Python 3.9.0 - it does fix that warning.

[dimpase]

Reviewer: Dima Pasechnik

[dimpase]

comment:6

lgtm

[vbraun]

comment:7

Merge conflict

[dimpase]

Changed commit from c53d261 to f291ad0

[dimpase]

comment:8

rebased over the latest beta

---

New commits:

f291ad0

some cleanup in pbori

[dimpase]

Changed branch from u/chapoton/30765 to public/30765

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

07b868b

some doc details in fglm.py

[sagetrac-git]

Changed commit from f291ad0 to 07b868b

[fchapoton]

comment:10

ok, I changed a few more details in the doc of fglm.

I will allow myself to set this back to positive.

[sagetrac-git]

Changed commit from 07b868b to de815db

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1 and set ticket back to needs_review. New commits:

de815db

further docstring improvement, ref. added

[dimpase]

comment:12

ok, this works, too.

[vbraun]

Changed branch from public/30765 to de815db