core: Properly track whether we should actually remove the PID file

Previously, PyLink spuriously removed PID files even if -n/--no-check-pid was set or if PID file checking caused PyLink to quit

coremods/control.py

@@ -24,13 +24,16 @@ def _print_remaining_threads():
     log.debug('shutdown(): Remaining threads: %s', ['%s/%s' % (t.name, t.ident) for t in threading.enumerate()])
 
 def _remove_pid():
-    # Remove our pid file.
     pidfile = "%s.pid" % conf.confname
-    log.info("Removing PID file %r.", pidfile)
-    try:
-        os.remove(pidfile)
-    except OSError:
-        log.exception("Failed to remove PID file %r, ignoring..." % pidfile)
+    if world._should_remove_pid:
+        # Remove our pid file.
+        log.info("Removing PID file %r.", pidfile)
+        try:
+            os.remove(pidfile)
+        except OSError:
+            log.exception("Failed to remove PID file %r, ignoring..." % pidfile)
+    else:
+        log.debug('Not removing PID file %s as world._should_remove_pid is False.' % pidfile)
 
 def _kill_plugins(irc=None):
     log.info("Shutting down plugins.")

launcher.py

@@ -50,6 +50,7 @@ def main():
     if not args.no_pid:
         with open('%s.pid' % conf.confname, 'w') as f:
             f.write(str(os.getpid()))
+        world._should_remove_pid = True
 
     # Import plugins first globally, because they can listen for events
     # that happen before the connection phase.

world.py

@@ -33,3 +33,6 @@ fallback_hostname = 'pylink.int'
 # Defines messages to be logged as soon as the log system is set up, for modules like conf that are
 # initialized before log. This is processed (and then not used again) when the log module loads.
 log_queue = deque()
+
+# Determines whether we have a PID file that needs to be removed.
+_should_remove_pid = False