server: add an error feedback mechanism for when the daemon fails to launch...
server: add an error feedback mechanism for when the daemon fails to launch
There's a recurring problem on Windows where `hg serve -d` will randomly fail to
spawn a detached process. The reason for the failure is completely hidden, and
it takes hours to get a single failure on my laptop. All this does is redirect
stdout/stderr of the child to a file until the lock file is freed, and then the
parent dumps it out if it fails to spawn.
I chose to put the output into the lock file because that is always cleaned up.
There's no way to report errors after that anyway. On Windows, killdaemons.py
is roughly `kill -9`, so this ensures that junk won't pile up.
This may end up being a case of EADDRINUSE. At least that's what I saw spit out
a few times (among other odd errors and missing output on Windows). But I also
managed to get the same thing on Fedora 26 by running test-hgwebdir.t with
--loop -j10 for several hours. Running `netstat` immediately after killing that
run printed a wall of sockets in the TIME_WAIT state, which were gone a couple
seconds later. I couldn't match up ports that failed, because --loop doesn't
print out the message about the port that was used. So maybe the fix is to
rotate the use of HGPORT[12] in the tests. But, let's collect some more data
first.
