Only create histories if client includes session cookie

lib/galaxy/webapps/base/webapp.py

@@ -650,11 +650,11 @@ def _ensure_valid_session(self, session_cookie: str, create: bool = True) -> Non
             galaxy_session = self.__create_new_session(prev_galaxy_session, user_for_new_session)
             galaxy_session_requires_flush = True
             self.galaxy_session = galaxy_session
-            if self.webapp.name == "galaxy":
-                self.get_or_create_default_history()
             self.__update_session_cookie(name=session_cookie)
         else:
             self.galaxy_session = galaxy_session
+            if self.webapp.name == "galaxy":
+                self.get_or_create_default_history()
         # Do we need to flush the session?
         if galaxy_session_requires_flush:
             self.sa_session.add(galaxy_session)
@@ -799,10 +799,10 @@ def _associate_user_history(self, user, prev_galaxy_session=None):
             and not users_last_session.current_history.deleted
         ):
             history = users_last_session.current_history
-        elif not history:
-            history = self.get_history(create=True, most_recent=True)
         if history not in self.galaxy_session.histories:
             self.galaxy_session.add_history(history)
+        if not history:
+            history = self.new_history()
         if history.user is None:
             history.user = user
         self.galaxy_session.current_history = history