do not try to load sessions that don't exist

CHANGELOG

@@ -11,9 +11,9 @@ nsmd now follows the XDG Base Directory Specifications:
  The old path ~/NSM Sessions/ is still supported and has priority, for now. This may be switched off in the future.
  Lockfiles fixed (see issue #gh-31)
  Lockfiles are now in $XDG_RUNTIME_DIR/nsm/
- Lockfiles now each contain the session path, the osc NSM_URL and the nsmd PID.
- New section in the API documentation to explain the above.
-
+ Lockfiles now each contain the session path, the osc NSM_URL and the nsmd PID
+ New section in the API documentation for the above.
+Fixes and guards against trying to load non-existing sessions and creating new sessions under existing names
 
 ## 2022-01-15 1.5.3
 Add [jackpatch] to terminal log output of jackpatch.

src/nsmd.cpp

@@ -1359,6 +1359,14 @@ tell_all_clients_session_is_loaded ( void )
 int
 load_session_file ( const char * path )
 {
+    //parameter "path" is the absolute path to the session including session root, without session.nsm
+
+    //First check if the session file actually exists, before closing the current one
+    if ( session_already_exists( basename( strdup(path )) ) != 0) {
+        WARNING ("Instructed to load %s which does not exist. Doing nothing.", path);
+        return ERR_NO_SUCH_FILE;
+    }
+
 
     if ( session_path && session_name ) {
         //We are already in a session. This is switch, or load during duplicate etc.