Use std::panic::set_hook to exit serve thread if serving fails

[joshrotenberg]

mdbook serve starts the warp server in a thread and then continues on to watch for changes. However, if the thread panics, for example, because the address is already in use, mdbook doesn't exit.

This change will explicitly call std::process::exit(1) from the thread if warp::serve panics.

Fixes #1545.

[ehuss]

Thanks!

I'm a bit surprised by this behavior in warp, it seems like it would be better to return a Result somewhere somehow.

[ehuss]

Oh, I see this is in Draft status, are you intending to make more changes?

[joshrotenberg]

Moved to ready. I was debating whether this was a good excuse to start some integration tests for the binary but that's probably better on its own.

[joshrotenberg]

I'm a bit surprised by this behavior in warp, it seems like it would be better to return a Result somewhere somehow.

Yeah, same. I dug around the docs and in some example code to see how others might handle it. My guess is that the usual use case is that you run the server in the main thread, so a panic would result in an exit anyway.

[ehuss]

Ah, sounds good, thanks!