The exit path for the debugger client has always been a little odd. We'd call a shutdown function which would destroy the client, then later call a stop function which would first make a new client, then stop it, then that one would get destroyed later. Made it so we stop and destroy just one client.
There was a race in the debugger protocol tests which send bad commands to the proxy and expect it to disconnect. If the proxy thread was fast enough it would mark the client as stopped, and we'd skip trying to get a new message after sending the bad command. This means missing one line of output in very rare cases. I've put in a wait to ensure that the client settles in the stopped state before continuing, to remove the race.
The [z]end command in hphpd runs the last manually entered snippet of php in "zend". If you typed 'z' before actually entering any php, it would segfault. Fixed a minor bug in Process::Exec, and present help if none entered. Also clarified that it will simply use your system's default php, and made it so you can override which exe to use with a hphpd config variable. The default is "php", since that is most commonly used.
Add a bit more usage logging for the debugger, and ensure that there is a common field between clients and servers thats easy to search on, i.e., sandbox id.
There was a similar-but-different event loop used when receiving command results from the server which was close, but not quite right. Unified it with the main event loop to ensure that all error cases are handled properly when we put up a prompt at a nested interrupt, like when hitting a breakpoint during an eval. The event loop is now shared, with a few different "kinds" to control some of the special needs of the loop when executed from a command. Most commands don't cause the server to run more PHP, so they don't change the machine state or cause more interrupts. But some do (Eval and Print) and certainly the top-level loop does, too. Made sure to throw a protocol error if any command causes this to happen when we don't expect it.
Cleanup a lot of hangs with either the debugger client or server in a variety of error conditions, mostly related to communication errors or the client or server exiting unexpectedly. One of the biggest fixes is that all cases where the client was left in a state where Ctrl-C wouldn't work have been fixed.
Remove lots of little snippets of dead code. If you see a function (or small set of functions/fields) deleted then it was actually dead.
I debated whether to keep throwing DebuggerClientExitException on the server, and I decided to keep it. I think it's reasonable that if you've got the server stopped and you quit the debugger that the request gets terminated rather than continuing to run.
I also considered a big change to the way Ctrl-C works, but ended up staying with what was there with just a bit of cleanup. We need to guard against people banging on Ctrl-C, which is a reasonable behavior, and I think it feels pretty reasonable with the updated message.
Finally, added many comments about how this stuff works.
Mike Magruder