bpo-41193: Ignore OSError in readline write_history() (GH-21279)

The write_history() atexit function of the readline completer now
ignores any OSError to ignore error if the filesystem is read-only,
instead of only ignoring FileNotFoundError and PermissionError.
(cherry picked from commit 0ab917e)

Co-authored-by: Victor Stinner <[email protected]>

Author: miss-islington

Lib/site.py

@@ -444,9 +444,9 @@ def register_readline():
             def write_history():
                 try:
                     readline.write_history_file(history)
-                except (FileNotFoundError, PermissionError):
-                    # home directory does not exist or is not writable
-                    # https://bugs.python.org/issue19891
+                except OSError:
+                    # bpo-19891, bpo-41193: Home directory does not exist
+                    # or is not writable, or the filesystem is read-only.
                     pass
 
             atexit.register(write_history)

Misc/NEWS.d/next/Library/2020-07-02-11-53-45.bpo-41193.8-Tnql.rst

@@ -0,0 +1,4 @@
+The ``write_history()`` atexit function of the readline completer now
+ignores any :exc:`OSError` to ignore error if the filesystem is read-only,
+instead of only ignoring :exc:`FileNotFoundError` and
+:exc:`PermissionError`.