1 files changed, 26 insertions, 17 deletions

diff --git a/src/modules/m_spanningtree/svsnick.cpp b/src/modules/m_spanningtree/svsnick.cpp
index 59973202d..bb21fc54d 100644
--- a/src/modules/m_spanningtree/svsnick.cpp
+++ b/src/modules/m_spanningtree/svsnick.cpp
@@ -21,41 +21,50 @@
 #include "inspircd.h"
 
 #include "main.h"
-#include "utils.h"
 #include "commands.h"
 
-CmdResult CommandSVSNick::Handle(const std::vector<std::string>& parameters, User *user)
+CmdResult CommandSVSNick::Handle(User* user, std::vector<std::string>& parameters)
 {
 	User* u = ServerInstance->FindNick(parameters[0]);
 
 	if (u && IS_LOCAL(u))
 	{
+		// 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
+		}
+
 		std::string nick = parameters[1];
 		if (isdigit(nick[0]))
 			nick = u->uuid;
 
-		// Don't update the TS if the nick is exactly the same
-		if (u->nick == nick)
-			return CMD_FAILURE;
-
 		time_t NickTS = ConvToInt(parameters[2]);
 		if (NickTS <= 0)
 			return CMD_FAILURE;
 
-		ModuleSpanningTree* st = (ModuleSpanningTree*)(Module*)creator;
-		st->KeepNickTS = true;
-		u->age = NickTS;
-
-		if (!u->ForceNickChange(nick.c_str()))
+		if (!u->ChangeNick(nick, NickTS))
 		{
 			/* buh. UID them */
-			if (!u->ForceNickChange(u->uuid.c_str()))
-			{
-				ServerInstance->Users->QuitUser(u, "Nickname collision");
-			}
+			u->ChangeNick(u->uuid);
 		}
-
-		st->KeepNickTS = false;
 	}
 
 	return CMD_SUCCESS;