Added flag for killable units

core/src/mindustry/entities/comp/ShieldComp.java

@@ -6,12 +6,14 @@ import mindustry.content.*;
 import mindustry.entities.*;
 import mindustry.game.*;
 import mindustry.gen.*;
+import mindustry.type.*;
 
 @Component
 abstract class ShieldComp implements Healthc, Posc{
     @Import float health, hitTime, x, y, healthMultiplier;
     @Import boolean dead;
     @Import Team team;
+    @Import UnitType type;
 
     /** Absorbs health damage. */
     float shield;
@@ -51,7 +53,7 @@ abstract class ShieldComp implements Healthc, Posc{
         hitTime = 1f;
         amount -= shieldDamage;
 
-        if(amount > 0){
+        if(amount > 0 && type.killable){
             health -= amount;
             if(health <= 0 && !dead){
                 kill();

core/src/mindustry/entities/comp/UnitComp.java

@@ -541,7 +541,7 @@ abstract class UnitComp implements Healthc, Physicsc, Hitboxc, Statusc, Teamc, I
 
     /** Actually destroys the unit, removing it and creating explosions. **/
     public void destroy(){
-        if(!isAdded()) return;
+        if(!isAdded() || !type.killable) return;
 
         float explosiveness = 2f + item().explosiveness * stack().amount * 1.53f;
         float flammability = item().flammability * stack().amount / 1.9f;
@@ -645,7 +645,7 @@ abstract class UnitComp implements Healthc, Physicsc, Hitboxc, Statusc, Teamc, I
     @Override
     @Replace
     public void kill(){
-        if(dead || net.client()) return;
+        if(dead || net.client() || !type.killable) return;
 
         //deaths are synced; this calls killed()
         Call.unitDeath(id);

core/src/mindustry/type/UnitType.java

@@ -68,7 +68,9 @@ public class UnitType extends UnlockableContent{
     public boolean logicControllable = true;
     public boolean playerControllable = true;
     public boolean allowedInPayloads = true;
-    /** TODO If true, core units will re-appear on this unit when respawning. */
+    /** If false, this unit does not take damage and cannot be kill() / destroy()-ed. */
+    public boolean killable = true;
+    /** If true, this core unit will "dock" to other units, making it re-appear when "undocking". */
     public boolean coreUnitDock = false;
     public boolean createWreck = true;
     public boolean createScorch = true;