half-closed connection to server prevents reconnection

[From
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=120901\]

If your home NAT box or so changes its external IP
address, such that
connections to IRC servers are broken, xchat will
*sometimes* become
unable to reconnect to some servers. The symptom is
that, even if you
reconnect (automatically or by hand), or even if you
explicitly
disconnect and connect again, it will connect to the
server and remain
in a state in which it doesn't send or receive
anything. Sometimes
the server will quickly break the connection, and xchat
will attempt
to reconnect over and over without ever succeeding.
Other times, it
just stays in this zombie state in which you can read
what's going on,
but no commands you send are honored. I can see that
there's a single
TCP connection between xchat and the IRC server using
lsof, and I can
see with tcpdump that the connection is fully
established and there's
some short exchange, but then xchat doesn't send
anything else.
strace confirmed it didn't write anything else to the
connection.

xchat 2.0.7

Steps to Reproduce:
1.Connect to some IRC servers
2.Reset your DSL connection such that your home
gateway/NAT box gets a
new IP address (re-connecting to a VPN server that
assigns IP
addresses dynamically works just as well)

Actual Results: Sometimes it gets into the weird state
described above

Expected Results: Sometimes it reconnects properly as
it should

Additional info:

The only way I know to fix the problem is to restart xchat.