Fail test test_misc.py::test_options_startup_param on ubuntu-24.04

[kav23alex]

When running tests on ubuntu-24.04, sometimes the test_misc.py::test_options_startup_param test fails with the error "FATAL: client sent partial pkt in startup phase"
reproduce:

a=`printf 'a%.0s' {1..1000}`; \
for i in `seq 100`; do \
echo "iter $i"; \
sudo -u postgres psql -d "host=127.0.0.1 port=15432 client_encoding=UTF8 connect_timeout=10 dbname=postgres options='-c timezone=test'" -c "select 1" &> /dev/null;  \
sudo -u postgres psql -d "host=127.0.0.1 port=15432 client_encoding=UTF8 connect_timeout=10 dbname=postgres options='-c timezone=$a'" &> /tmp/logmsg; \
grep "partial pkt" /tmp/logmsg && { echo "FOUND"; break; }; \
sleep 0.1; \
done

If you increase tcp_socket_buffer from 4096 to 8192, the error is not reproduced.

bouncer.ini

[databases]
postgres = port=5432 host=127.0.0.1 dbname=postgres user=postgres pool_size=2

[pgbouncer]
logfile = test.log
pidfile = test.pid

listen_addr = 127.0.0.1
listen_port = 15432
unix_socket_dir = /tmp

auth_type = trust
auth_file = userlist.txt
pool_mode = statement

; use a small tcp_socket_buffer so that we trigger EAGAIN more often in tests.
; Otherwise bugs caused by EAGAIN are hard to debug.
tcp_socket_buffer = 4096

[JelteF]

I created a fix for this in #1058 could you try that out and confirm that it indeed fixes your reproducing case too.