Fix TNT mod crash when entities disappear during explosion (#2616)

init.lua

@@ -163,9 +163,8 @@ local function entity_physics(pos, radius, drops)
 
 		local damage = (4 / dist) * radius
 		if obj:is_player() then
-			-- currently the engine has no method to set
+			-- we knock the player back 1.0 node, and slightly upwards
-			-- player velocity. See #2960
+			-- TODO: switch to add_player_velocity() introduced in 5.1
-			-- instead, we knock the player back 1.0 node, and slightly upwards
 			local dir = vector.normalize(vector.subtract(obj_pos, pos))
 			local moveoff = vector.multiply(dir, dist + 1.0)
 			local newpos = vector.add(pos, moveoff)
@@ -174,31 +173,35 @@ local function entity_physics(pos, radius, drops)
 
 			obj:set_hp(obj:get_hp() - damage)
 		else
-			local do_damage = true
-			local do_knockback = true
-			local entity_drops = {}
 			local luaobj = obj:get_luaentity()
-			local objdef = minetest.registered_entities[luaobj.name]
 
-			if objdef and objdef.on_blast then
+			-- object might have disappeared somehow
-				do_damage, do_knockback, entity_drops = objdef.on_blast(luaobj, damage)
+			if luaobj then
-			end
+				local do_damage = true
+				local do_knockback = true
+				local entity_drops = {}
+				local objdef = minetest.registered_entities[luaobj.name]
 
-			if do_knockback then
+				if objdef and objdef.on_blast then
-				local obj_vel = obj:get_velocity()
+					do_damage, do_knockback, entity_drops = objdef.on_blast(luaobj, damage)
-				obj:set_velocity(calc_velocity(pos, obj_pos,
+				end
-						obj_vel, radius * 10))
+
-			end
+				if do_knockback then
-			if do_damage then
+					local obj_vel = obj:get_velocity()
-				if not obj:get_armor_groups().immortal then
+					obj:set_velocity(calc_velocity(pos, obj_pos,
-					obj:punch(obj, 1.0, {
+							obj_vel, radius * 10))
-						full_punch_interval = 1.0,
+				end
-						damage_groups = {fleshy = damage},
+				if do_damage then
-					}, nil)
+					if not obj:get_armor_groups().immortal then
+						obj:punch(obj, 1.0, {
+							full_punch_interval = 1.0,
+							damage_groups = {fleshy = damage},
+						}, nil)
+					end
+				end
+				for _, item in pairs(entity_drops) do
+					add_drop(drops, item)
 				end
-			end
-			for _, item in pairs(entity_drops) do
-				add_drop(drops, item)
 			end
 		end
 	end