Fix startup when connecting to a running nsmd. Session path was switch with its name, which is the same when starting our own server

engine/nsmservercontrol.py

@@ -344,7 +344,7 @@ class NsmServerControl(object):
                 "/nsm/gui/client/pid" : self._reactCallback_clientPid,
                 "/nsm/gui/client/dirty" : self._reactCallback_clientDirty,
                 "/nsm/gui/server/message" : self._reactCallback_serverMessage,
-                "/nsm/gui/gui_announce" : self._reactCallback_guiAnnounce,
+                "/nsm/gui/gui_announce" : self._reactCallback_guiAnnounce, #we rarely receive that, especially not in init.
                 "/nsm/server/list" : self._reactCallback_serverList,
                 "/nsm/server/broadcast" : self._reactCallback_broadcast,
             }
@@ -581,6 +581,7 @@ class NsmServerControl(object):
         Returns session root as pathlib-path."""        
         resultArguments = self._blockingRequest(path="/nsm/gui/gui_announce", arguments=[], answerPath="/nsm/gui/session/root", answerArguments=[])
         if len(self._queue) == 1 and self._queue[0].oscpath == "/nsm/gui/gui_announce" and self._queue[0].params == ["hi"]:            
+            logger.info("Got 'hi'. We are now the registered nsmd GUI as per our initial /nsm/gui/gui_announce")
             self._queue.clear()            
         else:
             logging.error(f"For ValueError below: {[(m.oscpath, m.params) for m in self._queue]}")
@@ -833,9 +834,9 @@ class NsmServerControl(object):
 
     #Callbacks
     def _reactCallback_guiAnnounce(self, parameters:list):
-        """Acknowledge"""
+        """This should not happen, but let's keep it in in case of edge-case multi GUI scenarios"""
         assert parameters == ["hi"], parameters
-        logger.info("We got acknowledged as current nsmd GUI.")
+        logger.info("We got an unexpected 'hi', as if requesting gui_announce. Our own initial GUI announce as received and processed silently earlier already.")
 
     def _reactCallback_error(self, parameters:list):
         logger.error(parameters)
@@ -940,27 +941,35 @@ class NsmServerControl(object):
 
 
     def _reactCallback_activeSessionChanged(self, parameters:list):
-        """This is called when the session has already changed.
+        """We receive this trough /nsm/gui/session/name
-        Shortly before we receive /nsm/gui/session/session which indicates the attempt to create,
+        This is called when the session has already changed.        
-        I guess! :)
+        This also happens when you connect to a headless nsmd with a running session.
 
-        If you want to react to the attempt to open a session you need to use /nsm/gui/server/message ["Opening session FOO"]
+        We expect two parameters: [session name, session path] both of which could be "".
-        OR creating a new session, after which nsmd will open that session without a message.
+        If we start nsmd ourselves into an empty state we expect session name to be empty
+        
+        Shortly before we received /nsm/gui/session/session which indicates the attempt to create a
+        new one, I guess! :)
+
+        If you want to react to the attempt to open a session you need to use
+        /nsm/gui/server/message ["Opening session FOO"] OR creating a new session, after which nsmd
+        will open that session without a message.
 
         Empty string is "No session" or "Choose A Session" mode.
         """
         l = len(parameters)
         if l == 2:
-            shortName, nsmSessionName = parameters
+            nsmSessionName, sessionPath = parameters
-            if not shortName and not nsmSessionName: #No session loaded. We are in session-choosing mode.
+            if not nsmSessionName and not sessionPath: #No session loaded. We are in session-choosing mode.
+                logger.info("Session closed or never started. Choose-A-Session mode.")
                 self.internalState["currentSession"] = None
                 self.sessionClosedHook()
             else:
-                nsmSessionName = nsmSessionName.lstrip("/")
+                sessionPath = sessionPath.lstrip("/")
-                logger.info(f"Current Session changed. We are now {shortName} under {nsmSessionName}")
+                logger.info(f"Current Session changed. We are now {nsmSessionName} in {sessionPath}")
                 self.internalState["currentSession"] = nsmSessionName
                 #This is after the session, received after all programs have loaded.
-                #We have a counterpart as message reaction that signals the attempt to load.
+                #We have a counterpart-message reaction that signals the attempt to load.
                 self.sessionOpenReadyHook(self.sessionAsDict(nsmSessionName)) #notify the api->UI
                 for autoClientExecutableInPath in self._addToNextSession:
                     self.clientAdd(autoClientExecutableInPath)                    
@@ -1411,8 +1420,10 @@ class NsmServerControl(object):
         sessionFile = pathlib.Path(basePath, "session.nsm")
 
         if not sessionFile.exists():
-            logger.info("Got wrong session directory from nsmd. Race condition after delete? Project: " + repr(sessionFile))
+            #This is a reason to let the program exit.
-            return None
+            print (nsmSessionName)
+            logger.error("Got wrong session directory from nsmd. Race condition after delete? In any case a breaking error (please report). Quitting. Project was: " + repr(sessionFile))
+            sysexit() #return None switch to return None to let it crash and see the python traceback
 
         timestamp = datetime.fromtimestamp(sessionFile.stat().st_mtime).isoformat(sep=" ", timespec='minutes')
         entry["lastSavedDate"] = timestamp