Fix Hydraulics stops working when using setVehicleHandling with player inside vehicle

Client/game_sa/CVehicleSA.cpp

@@ -684,6 +684,17 @@ void CVehicleSA::RemoveVehicleUpgrade(DWORD dwModelID)
         push    dwModelID
         call    dwFunc
     }
+
+    // GTA SA only does this when CVehicle::ClearVehicleUpgradeFlags returns false.
+    // In the case of hydraulics and nitro, this function does not return false and the upgrade is never removed from the array
+    for (std::int16_t& upgrade : GetVehicleInterface()->m_upgrades)
+    {
+        if (upgrade == dwModelID)
+        {
+            upgrade = -1;
+            break;
+        }
+    }
 }
 
 bool CVehicleSA::DoesSupportUpgrade(const SString& strFrameName)
@@ -1322,49 +1333,41 @@ void CVehicleSA::RecalculateHandling()
     // Put it in our interface
     CVehicleSAInterface* pInt = GetVehicleInterface();
     unsigned int         uiHandlingFlags = m_pHandlingData->GetInterface()->uiHandlingFlags;
-    // user error correction - NOS_INST = NOS Installed t/f
-    // if nos is installed we need the flag set
-    if (pInt->m_upgrades[0] && pInt->m_upgrades[0] >= 1008 && pInt->m_upgrades[0] <= 1010)
+    bool                 hydralicsInstalled = false, nitroInstalled = false;
+
+    // We check whether the user has not set incorrect flags via handlingFlags in the case of nitro and hydraulics
+    // If this happened, we need to correct it
+    for (const std::int16_t& upgradeID : pInt->m_upgrades)
     {
-        // Flag not enabled?
-        if (uiHandlingFlags | HANDLING_NOS_Flag)
+        // Empty upgrades value is -1
+        if (upgradeID < 0)
+            continue;
+
+        // If NOS is installed we need set the flag
+        if ((upgradeID >= 1008 && upgradeID <= 1010) && !(uiHandlingFlags & HANDLING_NOS_Flag))
         {
-            // Set zee flag
             uiHandlingFlags |= HANDLING_NOS_Flag;
-            m_pHandlingData->SetHandlingFlags(uiHandlingFlags);
-        }
-    }
-    else
-    {
-        // Flag Enabled?
-        if (uiHandlingFlags & HANDLING_NOS_Flag)
-        {
-            // Unset the flag
-            uiHandlingFlags &= ~HANDLING_NOS_Flag;
-            m_pHandlingData->SetHandlingFlags(uiHandlingFlags);
+            nitroInstalled = true;
         }
-    }
-    // Hydraulics Flag fixing
-    if (pInt->m_upgrades[1] && pInt->m_upgrades[1] == 1087)
-    {
-        // Flag not enabled?
-        if (uiHandlingFlags | HANDLING_Hydraulics_Flag)
+
+        // If hydraulics is installed we need set the flag
+        if ((upgradeID == 1087) && !(uiHandlingFlags & HANDLING_Hydraulics_Flag))
         {
-            // Set zee flag
             uiHandlingFlags |= HANDLING_Hydraulics_Flag;
-            m_pHandlingData->SetHandlingFlags(uiHandlingFlags);
-        }
-    }
-    else
-    {
-        // Flag Enabled?
-        if (uiHandlingFlags & HANDLING_Hydraulics_Flag)
-        {
-            // Unset the flag
-            uiHandlingFlags &= ~HANDLING_Hydraulics_Flag;
-            m_pHandlingData->SetHandlingFlags(uiHandlingFlags);
+            hydralicsInstalled = true;
         }
     }
+
+    // If hydraulics isn't installed we need unset the flag
+    if ((!hydralicsInstalled) && (uiHandlingFlags & HANDLING_Hydraulics_Flag))
+        uiHandlingFlags &= ~HANDLING_Hydraulics_Flag;
+
+    // If NOS isn't installed we need unset the flag
+    if ((!nitroInstalled) && (uiHandlingFlags & HANDLING_NOS_Flag))
+        uiHandlingFlags &= ~HANDLING_NOS_Flag;
+
+    m_pHandlingData->SetHandlingFlags(uiHandlingFlags);
+
     pInt->dwHandlingFlags = uiHandlingFlags;
     pInt->m_fMass = m_pHandlingData->GetInterface()->fMass;
     pInt->m_fTurnMass = m_pHandlingData->GetInterface()->fTurnMass;            // * pGame->GetHandlingManager()->GetTurnMassMultiplier();