frag grenade shell wall bug resolution (discordia-space#8400)

grenade shells now universally qdel self on activation

code/modules/projectiles/projectile.dm

@@ -471,9 +471,13 @@
 	else
 		passthrough = (A.bullet_act(src, def_zone) == PROJECTILE_CONTINUE) //backwards compatibility
 		if(isturf(A))
-			for(var/obj/O in A)
+			if(QDELETED(src)) // we don't want bombs to explode once for every time bullet_act is called
+				on_impact(A)
+				invisibility = 101
+				return TRUE // see that next line? it can overload the server.
+			for(var/obj/O in A) // if src's bullet act spawns more objs, the list will increase,
 				if(O.density)
-					O.bullet_act(src)
+					O.bullet_act(src) // causing exponential growth due to the spawned obj spawning itself
 			for(var/mob/living/M in A)
 				attack_mob(M)
 

code/modules/projectiles/projectile/projectilegrenades.dm

@@ -21,7 +21,8 @@
 	grenade_effect(target)
 
 /obj/item/projectile/bullet/grenade/proc/grenade_effect(target)
-	return
+	qdel(src) // DO NOT ALLOW SRC TO SURVIVE THIS
+	SHOULD_CALL_PARENT(TRUE)
 
 /obj/item/projectile/bullet/grenade/blast
 	name = "blast shell"
@@ -30,6 +31,7 @@
 
 /obj/item/projectile/bullet/grenade/blast/grenade_effect(target)
 	explosion(get_turf(target), explosion_power, explosion_falloff)
+	. = ..()
 
 /obj/item/projectile/bullet/grenade/heatwave
 	name = "heatwave shell"
@@ -40,7 +42,8 @@
 	var/fire_stacks = TRUE
 
 /obj/item/projectile/bullet/grenade/heatwave/grenade_effect(target)
-    heatwave(target, heavy_range, weak_range, heat_damage, fire_stacks, penetration)
+	heatwave(target, heavy_range, weak_range, heat_damage, fire_stacks, penetration)
+	. = ..()
 
 /obj/item/projectile/bullet/grenade/frag
 	name = "frag shell"
@@ -66,6 +69,7 @@
 /obj/item/projectile/bullet/grenade/frag/grenade_effect(target)
 	fragment_explosion(target, range, f_type, f_amount, f_damage, f_step, same_turf_hit_chance)
 	explosion(get_turf(target), 60, 40)
+	. = ..()
 
 /obj/item/projectile/bullet/grenade/frag/sting/weak
 	name = "sting shell"
@@ -80,6 +84,7 @@
 
 /obj/item/projectile/bullet/grenade/emp/grenade_effect(target)
 	empulse(target, heavy_emp_range, light_emp_range)
+	. = ..()
 
 /obj/item/projectile/bullet/grenade/emp/low_yield
 	heavy_emp_range = 4
@@ -94,6 +99,7 @@
 /obj/item/projectile/bullet/grenade/handgrenade/grenade_effect(target)
 	var/obj/item/grenade/G = new hand_gren(src)
 	G.prime()
+	. = ..()
 
 /obj/item/projectile/bullet/grenade/handgrenade/teargas    // Because why not
 	name = "cs shell"