fix(Core/Spells): Prevent extra attack abilities from chain-proccing (#24806)

Co-authored-by: blinkysc <blinkysc@users.noreply.github.com>
Co-authored-by: trickerer <onlysuffering@gmail.com>

src/test/server/game/Spells/ExtraAttackChainProcTest.cpp

@@ -0,0 +1,149 @@
+/*
+ * This file is part of the AzerothCore Project. See AUTHORS file for Copyright information
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * @file ExtraAttackChainProcTest.cpp
+ * @brief Unit tests for extra attack chain-proc prevention
+ *
+ * Tests the logic from SpellAuraEffects.cpp:1245-1261 (CheckEffectProc):
+ * - Self-chain prevention (same extra attack spell can't proc itself)
+ * - Cross-chain prevention (Sword Specialization / Hack and Slash block all extra attack procs)
+ * - Non-blacklisted extra attack spells allow cross-proccing
+ * - Non-extra-attack procs are unaffected by the guard
+ */
+
+#include "ProcChanceTestHelper.h"
+#include "gtest/gtest.h"
+
+using namespace testing;
+
+// Use existing enum from Unit.h: SPELL_SWORD_SPECIALIZATIONIALIZATION (16459), SPELL_HACK_AND_SLASH (66923)
+constexpr uint32 SPELL_RECKONING       = 32746; // Reckoning (Paladin)
+constexpr uint32 SPELL_HAND_OF_JUSTICE = 15601; // Hand of Justice extra attack
+
+class ExtraAttackChainProcTest : public ::testing::Test
+{
+protected:
+    ProcChanceTestHelper::ExtraAttackProcConfig MakeConfig(
+        bool hasExtraAttacks, uint32 triggerSpellId, uint32 lastExtraAttack)
+    {
+        ProcChanceTestHelper::ExtraAttackProcConfig config;
+        config.triggeredSpellHasExtraAttacks = hasExtraAttacks;
+        config.triggerSpellId = triggerSpellId;
+        config.lastExtraAttackSpell = lastExtraAttack;
+        return config;
+    }
+};
+
+// =============================================================================
+// Normal proc (no extra attack in progress)
+// =============================================================================
+
+TEST_F(ExtraAttackChainProcTest, NormalProc_AllowedWhenNoExtraAttackInProgress)
+{
+    // lastExtraAttackSpell == 0 means no extra attack is executing
+    auto config = MakeConfig(true, SPELL_SWORD_SPECIALIZATION, 0);
+
+    EXPECT_FALSE(ProcChanceTestHelper::ShouldBlockExtraAttackChainProc(config))
+        << "Extra attack proc should be allowed when no extra attack is in progress";
+}
+
+// =============================================================================
+// Self-chain prevention
+// =============================================================================
+
+TEST_F(ExtraAttackChainProcTest, SelfChain_BlockedWhenSameSpell)
+{
+    // Sword Spec trying to proc during its own extra attack
+    auto config = MakeConfig(true, SPELL_SWORD_SPECIALIZATION, SPELL_SWORD_SPECIALIZATION);
+
+    EXPECT_TRUE(ProcChanceTestHelper::ShouldBlockExtraAttackChainProc(config))
+        << "Extra attack spell should not chain-proc itself";
+}
+
+// =============================================================================
+// Cross-chain prevention (blacklisted spells)
+// =============================================================================
+
+TEST_F(ExtraAttackChainProcTest, CrossChain_BlockedBySwordSpecialization)
+{
+    // Reckoning trying to proc during Sword Spec extra attack
+    auto config = MakeConfig(true, SPELL_RECKONING, SPELL_SWORD_SPECIALIZATION);
+
+    EXPECT_TRUE(ProcChanceTestHelper::ShouldBlockExtraAttackChainProc(config))
+        << "Sword Specialization extra attack should block all other extra attack procs";
+}
+
+TEST_F(ExtraAttackChainProcTest, CrossChain_BlockedByHackAndSlash)
+{
+    // Reckoning trying to proc during Hack and Slash extra attack
+    auto config = MakeConfig(true, SPELL_RECKONING, SPELL_HACK_AND_SLASH);
+
+    EXPECT_TRUE(ProcChanceTestHelper::ShouldBlockExtraAttackChainProc(config))
+        << "Hack and Slash extra attack should block all other extra attack procs";
+}
+
+// =============================================================================
+// Non-blacklisted extra attacks allow cross-proccing
+// =============================================================================
+
+TEST_F(ExtraAttackChainProcTest, DifferentExtraAttack_AllowedWhenNotBlacklisted)
+{
+    // Sword Spec trying to proc during Hand of Justice extra attack
+    // Hand of Justice (15601) is not blacklisted, so cross-proc is allowed
+    auto config = MakeConfig(true, SPELL_SWORD_SPECIALIZATION, SPELL_HAND_OF_JUSTICE);
+
+    EXPECT_FALSE(ProcChanceTestHelper::ShouldBlockExtraAttackChainProc(config))
+        << "Non-blacklisted extra attack spells should allow cross-proccing";
+}
+
+// =============================================================================
+// Non-extra-attack procs unaffected
+// =============================================================================
+
+TEST_F(ExtraAttackChainProcTest, NonExtraAttackProc_UnaffectedByExtraAttackState)
+{
+    // A proc that does NOT grant extra attacks should never be blocked,
+    // even during Sword Spec extra attack
+    auto config = MakeConfig(false, 12345, SPELL_SWORD_SPECIALIZATION);
+
+    EXPECT_FALSE(ProcChanceTestHelper::ShouldBlockExtraAttackChainProc(config))
+        << "Non-extra-attack procs should be unaffected by extra attack state";
+}
+
+// =============================================================================
+// Real spell scenarios
+// =============================================================================
+
+TEST_F(ExtraAttackChainProcTest, Reckoning_SelfChainBlocked)
+{
+    // Reckoning (32746) trying to proc during its own extra attack
+    auto config = MakeConfig(true, SPELL_RECKONING, SPELL_RECKONING);
+
+    EXPECT_TRUE(ProcChanceTestHelper::ShouldBlockExtraAttackChainProc(config))
+        << "Reckoning should not chain-proc itself";
+}
+
+TEST_F(ExtraAttackChainProcTest, Reckoning_AllowedDuringHandOfJustice)
+{
+    // Reckoning trying to proc during Hand of Justice extra attack
+    // Hand of Justice is not blacklisted, so Reckoning is allowed
+    auto config = MakeConfig(true, SPELL_RECKONING, SPELL_HAND_OF_JUSTICE);
+
+    EXPECT_FALSE(ProcChanceTestHelper::ShouldBlockExtraAttackChainProc(config))
+        << "Reckoning should be allowed during Hand of Justice extra attack";
+}