fix(Core/Spells): Port SPELL_ATTR3_INSTANT_TARGET_PROCS cascade proc suppression from TrinityCore (#24936)

Co-authored-by: blinkysc <blinkysc@users.noreply.github.com>
Co-authored-by: QAston <126822+QAston@users.noreply.github.com>

src/server/game/Entities/Unit/Unit.cpp

@@ -13058,11 +13058,28 @@ void Unit::TriggerAurasProcOnEvent(std::list<AuraApplication*>* myProcAuras, std
 
 void Unit::TriggerAurasProcOnEvent(ProcEventInfo& eventInfo, AuraApplicationProcContainer& aurasTriggeringProc)
 {
+    Spell const* triggeringSpell = eventInfo.GetProcSpell();
+    bool const disableProcs = triggeringSpell && triggeringSpell->IsProcDisabled();
+    if (disableProcs)
+        SetCantProc(true);
+
     for (auto const& [procEffectMask, aurApp] : aurasTriggeringProc)
     {
-        if (!aurApp->GetRemoveMode())
-            aurApp->GetBase()->TriggerProcOnEvent(procEffectMask, aurApp, eventInfo);
+        if (aurApp->GetRemoveMode())
+            continue;
+
+        SpellInfo const* spellInfo = aurApp->GetBase()->GetSpellInfo();
+        if (spellInfo->HasAttribute(SPELL_ATTR3_INSTANT_TARGET_PROCS))
+            SetCantProc(true);
+
+        aurApp->GetBase()->TriggerProcOnEvent(procEffectMask, aurApp, eventInfo);
+
+        if (spellInfo->HasAttribute(SPELL_ATTR3_INSTANT_TARGET_PROCS))
+            SetCantProc(false);
     }
+
+    if (disableProcs)
+        SetCantProc(false);
 }
 
 Player* Unit::GetSpellModOwner() const

src/server/game/Spells/Spell.h

@@ -565,6 +565,7 @@ public:
     bool IsNextMeleeSwingSpell() const;
     bool IsTriggered() const { return HasTriggeredCastFlag(TRIGGERED_FULL_MASK); };
     bool HasTriggeredCastFlag(TriggerCastFlags flag) const { return _triggeredCastFlags & flag; };
+    [[nodiscard]] bool IsProcDisabled() const { return HasTriggeredCastFlag(TRIGGERED_DISALLOW_PROC_EVENTS); }
     bool IsChannelActive() const { return m_caster->GetUInt32Value(UNIT_CHANNEL_SPELL) != 0; }
     bool IsAutoActionResetSpell() const;
     bool IsIgnoringCooldowns() const;

src/test/mocks/ProcChanceTestHelper.h

@@ -492,6 +492,40 @@ public:
         }
     }
 
+    // =============================================================================
+    // Cascade Proc Suppression - simulates Unit.cpp TriggerAurasProcOnEvent
+    // =============================================================================
+
+    /**
+     * @brief Configuration for simulating cascade proc suppression
+     *
+     * Models the two paths in TriggerAurasProcOnEvent that call SetCantProc():
+     * 1. Outer check: triggering spell has TRIGGERED_DISALLOW_PROC_EVENTS
+     * 2. Per-aura check: aura has SPELL_ATTR3_INSTANT_TARGET_PROCS (0x80000)
+     */
+    struct CascadeProcConfig
+    {
+        bool triggeringSpellIsProcDisabled = false;  // Spell::IsProcDisabled()
+        bool auraHasDisableProcAttr = false;         // SpellInfo::HasAttribute(SPELL_ATTR3_INSTANT_TARGET_PROCS)
+    };
+
+    /**
+     * @brief Returns true if cascading procs should be suppressed for this aura
+     *
+     * @param config Cascade proc configuration
+     * @return true if SetCantProc(true) would be active during this aura's proc
+     */
+    static bool ShouldSuppressCascadingProc(CascadeProcConfig const& config)
+    {
+        // Outer check: triggering spell disables all cascading procs
+        if (config.triggeringSpellIsProcDisabled)
+            return true;
+        // Per-aura check: aura itself suppresses cascading
+        if (config.auraHasDisableProcAttr)
+            return true;
+        return false;
+    }
+
     // =============================================================================
     // Conditions System - simulates SpellAuras.cpp:2232-2236
     // =============================================================================

src/test/mocks/SpellInfoTestHelper.h

@@ -96,6 +96,12 @@ public:
         return *this;
     }
 
+    TestSpellEntryHelper& WithAttributesEx3(uint32 attr)
+    {
+        _entry.AttributesEx3 = attr;
+        return *this;
+    }
+
     TestSpellEntryHelper& WithEffect(uint8 effIndex, uint32 effect, uint32 auraType = 0)
     {
         if (effIndex < MAX_SPELL_EFFECTS)
@@ -183,6 +189,12 @@ public:
         return *this;
     }
 
+    SpellInfoBuilder& WithAttributesEx3(uint32 attr)
+    {
+        _entryHelper.WithAttributesEx3(attr);
+        return *this;
+    }
+
     SpellInfoBuilder& WithEffect(uint8 effIndex, uint32 effect, uint32 auraType = 0)
     {
         _entryHelper.WithEffect(effIndex, effect, auraType);

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

@@ -0,0 +1,213 @@
+/*
+ * 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 CascadeProcSuppressionTest.cpp
+ * @brief Unit tests for cascade proc suppression via SPELL_ATTR3_INSTANT_TARGET_PROCS
+ *
+ * Tests the logic from Unit.cpp TriggerAurasProcOnEvent:
+ * - Outer check: Spell::IsProcDisabled() (TRIGGERED_DISALLOW_PROC_EVENTS) suppresses all cascade procs
+ * - Per-aura check: SPELL_ATTR3_INSTANT_TARGET_PROCS (0x80000) suppresses cascade for that aura
+ * - Normal spells/auras without these flags allow cascading
+ * - Both flags set simultaneously still suppresses correctly
+ */
+
+#include "ProcChanceTestHelper.h"
+#include "SpellInfoTestHelper.h"
+#include "gtest/gtest.h"
+
+using namespace testing;
+
+class CascadeProcSuppressionTest : public ::testing::Test
+{
+protected:
+    ProcChanceTestHelper::CascadeProcConfig MakeConfig(
+        bool isProcDisabled, bool hasDisableProcAttr)
+    {
+        ProcChanceTestHelper::CascadeProcConfig config;
+        config.triggeringSpellIsProcDisabled = isProcDisabled;
+        config.auraHasDisableProcAttr = hasDisableProcAttr;
+        return config;
+    }
+};
+
+// =============================================================================
+// Normal behavior (no suppression)
+// =============================================================================
+
+TEST_F(CascadeProcSuppressionTest, NormalSpellNormalAura_NotSuppressed)
+{
+    auto config = MakeConfig(false, false);
+
+    EXPECT_FALSE(ProcChanceTestHelper::ShouldSuppressCascadingProc(config))
+        << "Normal spell + normal aura should not suppress cascading procs";
+}
+
+// =============================================================================
+// IsProcDisabled (outer check - TRIGGERED_DISALLOW_PROC_EVENTS)
+// =============================================================================
+
+TEST_F(CascadeProcSuppressionTest, ProcDisabledSpell_NormalAura_Suppressed)
+{
+    auto config = MakeConfig(true, false);
+
+    EXPECT_TRUE(ProcChanceTestHelper::ShouldSuppressCascadingProc(config))
+        << "Triggered spell with DISALLOW_PROC_EVENTS should suppress all cascading procs";
+}
+
+TEST_F(CascadeProcSuppressionTest, ProcDisabledSpell_WithAttr_Suppressed)
+{
+    auto config = MakeConfig(true, true);
+
+    EXPECT_TRUE(ProcChanceTestHelper::ShouldSuppressCascadingProc(config))
+        << "Both flags set should still suppress (double-suppress doesn't break)";
+}
+
+// =============================================================================
+// SPELL_ATTR3_INSTANT_TARGET_PROCS (per-aura check)
+// =============================================================================
+
+TEST_F(CascadeProcSuppressionTest, NormalSpell_AuraWithAttr_Suppressed)
+{
+    auto config = MakeConfig(false, true);
+
+    EXPECT_TRUE(ProcChanceTestHelper::ShouldSuppressCascadingProc(config))
+        << "Aura with SPELL_ATTR3_INSTANT_TARGET_PROCS should suppress cascading procs";
+}
+
+// =============================================================================
+// SpellInfo attribute verification via SpellInfoBuilder
+// =============================================================================
+
+TEST_F(CascadeProcSuppressionTest, SpellInfo_WithAttr_HasAttributeReturnsTrue)
+{
+    auto spellInfo = SpellInfoBuilder()
+        .WithId(99001)
+        .WithAttributesEx3(SPELL_ATTR3_INSTANT_TARGET_PROCS)
+        .BuildUnique();
+
+    EXPECT_TRUE(spellInfo->HasAttribute(SPELL_ATTR3_INSTANT_TARGET_PROCS))
+        << "SpellInfo built with 0x80000 should report HasAttribute true";
+}
+
+TEST_F(CascadeProcSuppressionTest, SpellInfo_WithoutAttr_HasAttributeReturnsFalse)
+{
+    auto spellInfo = SpellInfoBuilder()
+        .WithId(99002)
+        .WithAttributesEx3(0)
+        .BuildUnique();
+
+    EXPECT_FALSE(spellInfo->HasAttribute(SPELL_ATTR3_INSTANT_TARGET_PROCS))
+        << "SpellInfo built with 0 should report HasAttribute false";
+}
+
+TEST_F(CascadeProcSuppressionTest, SpellInfo_WithMixedBits_HasAttributeReturnsTrue)
+{
+    // 0x80001 = SPELL_ATTR3_INSTANT_TARGET_PROCS | SPELL_ATTR3_PVP_ENABLING (bit 0)
+    auto spellInfo = SpellInfoBuilder()
+        .WithId(99003)
+        .WithAttributesEx3(0x00080001)
+        .BuildUnique();
+
+    EXPECT_TRUE(spellInfo->HasAttribute(SPELL_ATTR3_INSTANT_TARGET_PROCS))
+        << "Other bits in AttributesEx3 should not interfere with attribute detection";
+}
+
+// =============================================================================
+// Real spell scenarios (data-driven)
+// These spells have SPELL_ATTR3_INSTANT_TARGET_PROCS (0x80000) in DBC
+// =============================================================================
+
+struct RealSpellTestCase
+{
+    const char* name;
+    uint32 spellId;
+    bool hasAttr;  // Whether the spell has SPELL_ATTR3_INSTANT_TARGET_PROCS
+};
+
+class CascadeProcRealSpellTest : public ::testing::TestWithParam<RealSpellTestCase> {};
+
+TEST_P(CascadeProcRealSpellTest, VerifySuppressionForRealSpell)
+{
+    auto const& tc = GetParam();
+
+    // Build a SpellInfo mimicking the real spell's AttributesEx3
+    auto spellInfo = SpellInfoBuilder()
+        .WithId(tc.spellId)
+        .WithAttributesEx3(tc.hasAttr ? SPELL_ATTR3_INSTANT_TARGET_PROCS : 0)
+        .BuildUnique();
+
+    // Verify attribute detection matches expectation
+    EXPECT_EQ(spellInfo->HasAttribute(SPELL_ATTR3_INSTANT_TARGET_PROCS), tc.hasAttr)
+        << tc.name << " (spell " << tc.spellId << ") attribute detection mismatch";
+
+    // Verify cascade suppression matches attribute presence
+    ProcChanceTestHelper::CascadeProcConfig config;
+    config.triggeringSpellIsProcDisabled = false;
+    config.auraHasDisableProcAttr = tc.hasAttr;
+
+    EXPECT_EQ(ProcChanceTestHelper::ShouldSuppressCascadingProc(config), tc.hasAttr)
+        << tc.name << " (spell " << tc.spellId << ") cascade suppression mismatch";
+}
+
+INSTANTIATE_TEST_SUITE_P(
+    CascadeProcSuppression,
+    CascadeProcRealSpellTest,
+    ::testing::Values(
+        // Spells WITH SPELL_ATTR3_INSTANT_TARGET_PROCS
+        RealSpellTestCase{"Seal Fate",             14195, true},
+        RealSpellTestCase{"Sword Specialization",  12281, true},
+        RealSpellTestCase{"Reckoning",             20178, true},
+        RealSpellTestCase{"Flurry",                16257, true},
+        // Counter-example: spell WITHOUT the attribute
+        RealSpellTestCase{"Eviscerate",            26865, false}
+    ),
+    [](testing::TestParamInfo<RealSpellTestCase> const& info) {
+        // Generate readable test name from spell name (replace spaces)
+        std::string name = info.param.name;
+        std::replace(name.begin(), name.end(), ' ', '_');
+        return name;
+    }
+);
+
+// =============================================================================
+// Nesting behavior - both flags simultaneously
+// =============================================================================
+
+TEST_F(CascadeProcSuppressionTest, BothFlagsSet_StillSuppressed)
+{
+    auto config = MakeConfig(true, true);
+
+    EXPECT_TRUE(ProcChanceTestHelper::ShouldSuppressCascadingProc(config))
+        << "Both IsProcDisabled and INSTANT_TARGET_PROCS set should still suppress";
+}
+
+TEST_F(CascadeProcSuppressionTest, OnlyOuterFlag_Suppressed)
+{
+    auto config = MakeConfig(true, false);
+
+    EXPECT_TRUE(ProcChanceTestHelper::ShouldSuppressCascadingProc(config))
+        << "Only IsProcDisabled should be sufficient to suppress";
+}
+
+TEST_F(CascadeProcSuppressionTest, OnlyPerAuraFlag_Suppressed)
+{
+    auto config = MakeConfig(false, true);
+
+    EXPECT_TRUE(ProcChanceTestHelper::ShouldSuppressCascadingProc(config))
+        << "Only INSTANT_TARGET_PROCS should be sufficient to suppress";
+}