hard-crash when proxy activated but unable to connect #1430

I have no proxy setup on my local machine, so setting one will for sure not work and is intended to reproduce this.

Steps to reproduce:

1. start Bitcoin-Qt (compiled from current master)
2. enable proxy and use default settings
3. exit
4. restart Bitcoin-Qt
5. exit
6. crash

debug.log shows in the end: socket select error 10022 ERROR: GetMyExternalIP() : connection to 216.146.39.70:80 failed Bitcoin exited select() for connection failed: 10038 ERROR: GetMyExternalIP() : connection to 212.117.175.194:80 failed ThreadOpenConnections exited

So I guess it has to do with ThreadOpenConnections not cleanly exiting, perhaps because we don't detect or handle such connection problems. This needs a deep look by @sipa I think.

Btw. the proxy setting in the Qt GUI needs a re-start, right? It's not changed on the fly?

Hmm, I cannot reproduce, but I suppose this is related to an attemped socks connection that takes a long time to timeout, longer than the shutdown code waits for lingering threads.

The solution is either implementing limited timeout for proxy connections, which should be done anyway, I believe, or reworking the threading model to use boost threads and interruption points instead of the current code that continuously needs to check fShutdown.

This seems fixed with current master (I can't reproduce on main- or testnet), so closing this.