> In the past, I was lazy and just added more and more patterns to ignore on stderr, but this approach doesn't work in the long term: gdb evolves frequently, and there are always new messages.

A recent example: test_gdb fails on Fedora because a warning which should not prevent to test python-gdb.py commands:

"Missing separate debuginfo for /lib/ld-linux-aarch64.so.1"

Moreover, Fedora also suggests a command to install missing package in this case:

"Try: dnf --enablerepo='*debug*' install ..."

https://bugzilla.redhat.com/show_bug.cgi?id=1721483