From 9cd7e7978d774b36339085b89b0b1fce3705f399 Mon Sep 17 00:00:00 2001
From: Kelsi <kelsihates2fa@gmail.com>
Date: Wed, 11 Mar 2026 02:49:37 -0700
Subject: [PATCH] fix: correct SMSG_DISPEL_FAILED packet format and improve
 message

WotLK sends spellId(4) + packed_guid caster + packed_guid victim, while
TBC/Classic sends full uint64 caster + uint64 victim + spellId(4).
The previous handler assumed TBC format unconditionally, causing incorrect
reads in WotLK mode.

Also use the spell name cache to display "Purge failed to dispel." rather
than a raw "Dispel failed! (spell N)" message.
---
 src/game/game_handler.cpp | 32 ++++++++++++++++++++++++++------
 1 file changed, 26 insertions(+), 6 deletions(-)

diff --git a/src/game/game_handler.cpp b/src/game/game_handler.cpp
index 071a6e72..d7867113 100644
--- a/src/game/game_handler.cpp
+++ b/src/game/game_handler.cpp
@@ -2864,13 +2864,33 @@ void GameHandler::handlePacket(network::Packet& packet) {
             handleAuraUpdate(packet, true);
             break;
         case Opcode::SMSG_DISPEL_FAILED: {
-            // casterGuid(8) + victimGuid(8) + spellId(4) [+ failing spellId(4)...]
-            if (packet.getSize() - packet.getReadPos() >= 20) {
-                /*uint64_t casterGuid =*/ packet.readUInt64();
-                /*uint64_t victimGuid =*/ packet.readUInt64();
-                uint32_t spellId = packet.readUInt32();
+            // WotLK:       uint32 dispelSpellId + packed_guid caster + packed_guid victim
+            //              [+ count × uint32 failedSpellId]
+            // TBC/Classic: uint64 caster + uint64 victim + uint32 spellId
+            //              [+ count × uint32 failedSpellId]
+            const bool dispelTbcLike = isClassicLikeExpansion() || isActiveExpansion("tbc");
+            uint32_t dispelSpellId = 0;
+            if (dispelTbcLike) {
+                if (packet.getSize() - packet.getReadPos() < 20) break;
+                /*uint64_t caster =*/ packet.readUInt64();
+                /*uint64_t victim =*/ packet.readUInt64();
+                dispelSpellId = packet.readUInt32();
+            } else {
+                if (packet.getSize() - packet.getReadPos() < 4) break;
+                dispelSpellId = packet.readUInt32();
+                if (packet.getSize() - packet.getReadPos() < 1) break;
+                /*uint64_t caster =*/ UpdateObjectParser::readPackedGuid(packet);
+                if (packet.getSize() - packet.getReadPos() < 1) break;
+                /*uint64_t victim =*/ UpdateObjectParser::readPackedGuid(packet);
+            }
+            {
+                loadSpellNameCache();
+                auto it = spellNameCache_.find(dispelSpellId);
                 char buf[128];
-                std::snprintf(buf, sizeof(buf), "Dispel failed! (spell %u)", spellId);
+                if (it != spellNameCache_.end() && !it->second.name.empty())
+                    std::snprintf(buf, sizeof(buf), "%s failed to dispel.", it->second.name.c_str());
+                else
+                    std::snprintf(buf, sizeof(buf), "Dispel failed! (spell %u)", dispelSpellId);
                 addSystemChatMessage(buf);
             }
             break;