Remove all the project code.
* This will break multiple plugins. * This breaks how users interact with projects. * This is the removal of an existing capability. * Users aren't given any choice in the matter. * etc.
... who will delete the session files?
The same entity who deletes the thumbnail cache. The users, if they care enough about it.
It would be simple to keep a list (in `geany-[hash].session.conf`) of previously seen project files and to clean up session files (every restart, after *n* restarts, daily, weekly, monthly, yearly, never, whatever). (Users with lots of transient config files could choose longer cleanup intervals or "never".)
I remember @kugel- being worried about that when geany.conf and session.conf were side by side, although I don't remember the context of that discussion.
Apparently no longer an issue anymore since the session_split branch has been merged without addressing it.