+ // The 4th parameter is optional and it is the expected nick TS of the target user. If this parameter is
+ // present and it doesn't match the user's nick TS, the SVSNICK is not acted upon.
+ // This makes it possible to detect the case when services wants to change the nick of a user, but the
+ // user changes their nick before the SVSNICK arrives, making the SVSNICK nick change (usually to a guest nick)
+ // unnecessary. Consider the following for example:
+ //
+ // 1. test changes nick to Attila which is protected by services
+ // 2. Services SVSNICKs the user to Guest12345
+ // 3. Attila changes nick to Attila_ which isn't protected by services
+ // 4. SVSNICK arrives
+ // 5. Attila_ gets his nick changed to Guest12345 unnecessarily
+ //
+ // In this case when the SVSNICK is processed the target has already changed his nick to something
+ // which isn't protected, so changing the nick again to a Guest nick is not desired.
+ // However, if the expected nick TS parameter is present in the SVSNICK then the nick change in step 5
+ // won't happen because the timestamps won't match.
+ if (parameters.size() > 3)
+ {
+ time_t ExpectedTS = ConvToInt(parameters[3]);
+ if (u->age != ExpectedTS)
+ return CMD_FAILURE; // Ignore SVSNICK
+ }
+