[Originally reported as https://bugzilla.redhat.com/show_bug.cgi?id=1852941.]

$ touch ~/foo
touch: cannot touch '/home/fedora/foo': Read-only file system
$ python
Python 3.9.0b3 (default, Jun 10 2020, 00:00:00) 
[GCC 10.1.1 20200507 (Red Hat 10.1.1-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> ^D
Error in atexit._run_exitfuncs:
Traceback (most recent call last):
  File "/usr/lib64/python3.9/site.py", line 462, in write_history
    readline.write_history_file(history)
OSError: [Errno 30] Read-only file system

Looking at /usr/lib64/python3.9/site.py, it already silently skips
PermissionError. If a user is running with the file system in ro mode,
they almost certainly are aware of the fact, since this is done either
on purpose or as a result of disk corruption, and the traceback from
python is not useful. Suppression of PermissionError was added in b2499669ef2e6dc9a2cdb49b4dc498e078167e26.

Version-Release number of selected component (if applicable):
python3-3.9.0~b3-1.fc33.x86_64

New changeset 0ab917e07ed64c6bfde6f6e791f9b28acc97b510 by Victor Stinner in branch 'master':
bpo-41193: Ignore OSError in readline write_history() (GH-21279)
https://github.com/python/cpython/commit/0ab917e07ed64c6bfde6f6e791f9b28acc97b510

New changeset 53d2b715d10e5c81cb9c86fd25e88ace4e41bc25 by Miss Islington (bot) in branch '3.8':
bpo-41193: Ignore OSError in readline write_history() (GH-21279)
https://github.com/python/cpython/commit/53d2b715d10e5c81cb9c86fd25e88ace4e41bc25

New changeset 0b4c87ef8f88a4c4c325e964fa4919cef3997605 by Miss Islington (bot) in branch '3.9':
bpo-41193: Ignore OSError in readline write_history() (GH-21279)
https://github.com/python/cpython/commit/0b4c87ef8f88a4c4c325e964fa4919cef3997605

Thanks Zbyszek for your bug report. It's now fixed in 3.8, 3.9 and master branches.

Wow, that was quick. Thanks!

Well, two errors were already ignored (bpo-19891). I just made the "except" more generic. I don't think that we can do anything more useless than ignoring the error if the filesystem is read-only. I don't think that a warning would be useful.