2 files changed, 23 insertions, 8 deletions

diff --git a/src/modules/m_spanningtree/fjoin.cpp b/src/modules/m_spanningtree/fjoin.cpp
index 8846b2fbc..7b4fa06bd 100644
--- a/src/modules/m_spanningtree/fjoin.cpp
+++ b/src/modules/m_spanningtree/fjoin.cpp
@@ -134,11 +134,13 @@ CmdResult CommandFJoin::Handle(const std::vector<std::string>& params, User *src
 			while ((*unparsedmodes) && (*unparsedmodes != ','))
 			{
 				ModeHandler *mh = ServerInstance->Modes->FindMode(*unparsedmodes, MODETYPE_CHANNEL);
-				if (mh)
-					modes += *unparsedmodes;
-				else
+				if (!mh)
+				{
+					ServerInstance->Logs->Log("m_spanningtree", SPARSE, "Unrecognised mode %c, dropping link", *unparsedmodes);
 					return CMD_INVALID;
+				}
 
+				modes += *unparsedmodes;
 				usr++;
 				unparsedmodes++;
 			}
diff --git a/src/modules/m_spanningtree/treesocket2.cpp b/src/modules/m_spanningtree/treesocket2.cpp
index 0628c900a..15a7898ed 100644
--- a/src/modules/m_spanningtree/treesocket2.cpp
+++ b/src/modules/m_spanningtree/treesocket2.cpp
@@ -415,18 +415,31 @@ void TreeSocket::ProcessConnectedLine(std::string& prefix, std::string& command,
 	else
 	{
 		Command* cmd = ServerInstance->Parser->GetHandler(command);
-		CmdResult res = CMD_INVALID;
-		if (cmd && params.size() >= cmd->min_params)
+		
+		if (!cmd)
 		{
-			res = cmd->Handle(params, who);
+			irc::stringjoiner pmlist(" ", params, 0, params.size() - 1);
+			ServerInstance->Logs->Log("m_spanningtree", SPARSE, "Unrecognised S2S command :%s %s %s",
+				who->uuid.c_str(), command.c_str(), pmlist.GetJoined().c_str());
+			SendError("Unrecognised command '" + command + "' -- possibly loaded mismatched modules");
+		}
+
+		if (params.size() < cmd->min_params)
+		{
+			irc::stringjoiner pmlist(" ", params, 0, params.size() - 1);
+			ServerInstance->Logs->Log("m_spanningtree", SPARSE, "Insufficient parameters for S2S command :%s %s %s",
+				who->uuid.c_str(), command.c_str(), pmlist.GetJoined().c_str());
+			SendError("Insufficient parameters for command '" + command + "'");
 		}
 
+		CmdResult res = cmd->Handle(params, who);
+
 		if (res == CMD_INVALID)
 		{
 			irc::stringjoiner pmlist(" ", params, 0, params.size() - 1);
-			ServerInstance->Logs->Log("spanningtree", SPARSE, "Invalid S2S command :%s %s %s",
+			ServerInstance->Logs->Log("m_spanningtree", SPARSE, "Error handling S2S command :%s %s %s",
 				who->uuid.c_str(), command.c_str(), pmlist.GetJoined().c_str());
-			SendError("Unrecognised or malformed command '" + command + "' -- possibly loaded mismatched modules");
+			SendError("Error handling '" + command + "' -- possibly loaded mismatched modules");
 		}
 		if (res == CMD_SUCCESS)
 			Utils->RouteCommand(route_back_again, command, params, who);