Add pcall wrapper to prevent server crashes when advtrains throws an error

Instead, read save files again and restore state before the crash
Rebased to latest commit

advtrains/advtrains/atc.lua

@@ -92,12 +92,17 @@ advtrains.register_tracks("default", {
 		return {
 			after_place_node=apn_func,
 			after_dig_node=function(pos)
+			return advtrains.pcall(function()
+
 				advtrains.invalidate_all_paths()
 				advtrains.ndb.clear(pos)
 				local pts=minetest.pos_to_string(pos)
 				atc.controllers[pts]=nil
+			end)
 			end,
 			on_receive_fields = function(pos, formname, fields, player)
+			return advtrains.pcall(function()
+
 				if advtrains.is_protected(pos, player:get_player_name()) then
 					minetest.record_protection_violation(pos, player:get_player_name())
 					return
@@ -135,6 +140,7 @@ advtrains.register_tracks("default", {
 						atc.send_command(pos)
 					end
 				end
+			end)
 			end,
 			advtrains = {
 				on_train_enter = function(pos, train_id)

advtrains/advtrains/couple.lua

@@ -31,6 +31,8 @@ minetest.register_entity("advtrains:discouple", {
 	end,
 	get_staticdata=function() return "DISCOUPLE" end,
 	on_punch=function(self, player)
+	return advtrains.pcall(function()
+
 		--only if player owns at least one wagon next to this
 		local own=player:get_player_name()
 		if self.wagon.owner and self.wagon.owner==own and not self.wagon.lock_couples then
@@ -54,8 +56,11 @@ minetest.register_entity("advtrains:discouple", {
 		else
 			minetest.chat_send_player(own, attrans("You need to own at least one neighboring wagon to destroy this couple."))
 		end
+	end)
 	end,
 	on_step=function(self, dtime)
+	return advtrains.pcall(function()
+
 		local t=os.clock()
 		if not self.wagon then
 			self.object:remove()
@@ -77,6 +82,7 @@ minetest.register_entity("advtrains:discouple", {
 			self.updatepct_timer=2
 		end
 		atprintbm("discouple_step", t)
+	end)
 	end,
 })
 
@@ -98,16 +104,21 @@ minetest.register_entity("advtrains:couple", {
 	initial_sprite_basepos = {x=0, y=0},
 	
 	is_couple=true,
-	on_activate=function(self, staticdata) 
+	on_activate=function(self, staticdata)
+	return advtrains.pcall(function()
+
 		if staticdata=="COUPLE" then
 			--couple entities have no right to exist further...
 			atprint("Couple loaded from staticdata, destroying")
 			self.object:remove()
 			return
 		end
+	end)
 	end,
 	get_staticdata=function(self) return "COUPLE" end,
 	on_rightclick=function(self, clicker)
+	return advtrains.pcall(function()
+
 		if not self.train_id_1 or not self.train_id_2 then return end
 		
 		local id1, id2=self.train_id_1, self.train_id_2
@@ -128,8 +139,11 @@ minetest.register_entity("advtrains:couple", {
 		end
 		atprint("Coupled trains", id1, id2)
 		self.object:remove()
+	end)
 	end,
 	on_step=function(self, dtime)
+	return advtrains.pcall(function()
+
 		local t=os.clock()
 		if not self.train_id_1 or not self.train_id_2 then atprint("Couple: train ids not set!") self.object:remove() return end
 		local train1=advtrains.trains[self.train_id_1]
@@ -167,5 +181,6 @@ minetest.register_entity("advtrains:couple", {
 			end
 		end
 		atprintbm("couple step", t)
+	end)
 	end,
 }) 

advtrains/advtrains/init.lua

@@ -9,6 +9,29 @@ end
 
 advtrains = {trains={}, wagon_save={}, player_to_train_mapping={}}
 
+--pcall
+local no_action=true
+function advtrains.pcall(fun)
+	if no_action then return end
+	
+	local succ, err, return1, return2, return3, return4=pcall(fun)
+	if not succ then
+		atwarn("Lua Error occured: ", err)
+		atwarn("Restoring saved state in 1 second...")
+		no_action=true
+		--read last save state and continue, as if server was restarted
+		for aoi, le in pairs(minetest.luaentities) do
+			if le.is_wagon then
+				le.object:remove()
+			end
+		end
+		minetest.after(1, advtrains.load)
+	else
+		return err, return1, return2, return3, return4
+	end
+end
+
+
 advtrains.modpath = minetest.get_modpath("advtrains")
 
 function advtrains.print_concat_table(a)
@@ -94,6 +117,9 @@ dofile(advtrains.modpath.."/craft_items.lua")
 --load/save
 
 advtrains.fpath=minetest.get_worldpath().."/advtrains"
+
+function advtrains.load()
+
 local file, err = io.open(advtrains.fpath, "r")
 if not file then
 	minetest.log("error", " Failed to read advtrains save data from file "..advtrains.fpath..": "..(err or "Unknown Error"))
@@ -142,6 +168,10 @@ else
 	end
 	file:close()
 end
+no_action=false
+
+end
+advtrains.load()
 
 advtrains.save = function()
 	--atprint("saving")

advtrains/advtrains/nodedb.lua

@@ -203,6 +203,8 @@ minetest.register_abm({
         nodenames = {"group:save_in_nodedb"},
         run_at_every_load = true,
         action = function(pos, node)
+        return advtrains.pcall(function()
+
 			local cid=ndbget(pos.x, pos.y, pos.z)
 			if cid then
 				--if in database, detect changes and apply.
@@ -227,14 +229,18 @@ minetest.register_abm({
 				atprint("nodedb: ", pos, "not in database")
 				ndb.update(pos, node)
 			end
+		end)
         end,
         interval=10,
         chance=1,
     })
     
 minetest.register_on_dignode(function(pos, oldnode, digger)
+return advtrains.pcall(function()
+
 	ndb.clear(pos)
 end)
+end)
 
 function ndb.get_nodes()
 	return ndb_nodes

advtrains/advtrains/trackplacer.lua

@@ -187,6 +187,8 @@ function tp.register_track_placer(nnprefix, imgprefix, dispname)
 		wield_image = imgprefix.."_placer.png",
 		groups={},
 		on_place = function(itemstack, placer, pointed_thing)
+		return advtrains.pcall(function()
+
 		        local name = placer:get_player_name()
 			if not name then
 			   return itemstack
@@ -207,6 +209,7 @@ function tp.register_track_placer(nnprefix, imgprefix, dispname)
 				end
 			end
 			return itemstack
+		end)
 		end,
 	})
 end
@@ -220,6 +223,7 @@ minetest.register_craftitem("advtrains:trackworker",{
 	wield_image = "advtrains_trackworker.png",
 	stack_max = 1,
 	on_place = function(itemstack, placer, pointed_thing)
+	return advtrains.pcall(function()
 		local name = placer:get_player_name()
 		if not name then
 			return
@@ -260,8 +264,11 @@ minetest.register_craftitem("advtrains:trackworker",{
 				advtrains.ndb.swap_node(pos, {name=nnprefix.."_"..suffix..modext[modpos+1], param2=node.param2})
 			end
 		end
+	end)
 	end,
 	on_use=function(itemstack, user, pointed_thing)
+	return advtrains.pcall(function()
+
 	        local name = user:get_player_name()
 		if not name then
 		   return
@@ -292,6 +299,7 @@ minetest.register_craftitem("advtrains:trackworker",{
 		else
 			atprint(name, dump(tp.tracks))
 		end
+	end)
 	end,
 })
 

advtrains/advtrains/trainlogic.lua

@@ -40,6 +40,8 @@ advtrains.save_interval=10
 advtrains.save_timer=advtrains.save_interval
 
 minetest.register_globalstep(function(dtime_mt)
+return advtrains.pcall(function()
+
 	--limit dtime: if trains move too far in one step, automation may cause stuck and wrongly braking trains
 	local dtime=dtime_mt
 	if dtime>0.2 then
@@ -81,8 +83,11 @@ minetest.register_globalstep(function(dtime_mt)
 	atprintbm("trainsteps", t)
 	endstep()
 end)
+end)
 
 minetest.register_on_joinplayer(function(player)
+return advtrains.pcall(function()
+
 	local pname=player:get_player_name()
 	local id=advtrains.player_to_train_mapping[pname]
 	if id then
@@ -101,8 +106,11 @@ minetest.register_on_joinplayer(function(player)
 		end
 	end
 end)
+end)
 
 minetest.register_on_dieplayer(function(player)
+return advtrains.pcall(function()
+
 	local pname=player:get_player_name()
 	local id=advtrains.player_to_train_mapping[pname]
 	if id then
@@ -117,6 +125,7 @@ minetest.register_on_dieplayer(function(player)
 		end
 	end
 end)
+end)
 --[[
 train step structure:
 

advtrains/advtrains/wagons.lua

@@ -50,6 +50,7 @@ function wagon:on_activate(sd_uid, dtime_s)
 end
 
 function wagon:get_staticdata()
+return advtrains.pcall(function()
 	if not self:ensure_init() then return end
 	atprint("[wagon "..((self.unique_id and self.unique_id~="" and self.unique_id) or "no-id").."]: saving to wagon_save")
 	--serialize inventory, if it has one
@@ -63,6 +64,7 @@ function wagon:get_staticdata()
 	advtrains.wagon_save[self.unique_id].name=nil
 	advtrains.wagon_save[self.unique_id].object=nil
 	return self.unique_id
+end)
 end
 --returns: uid of wagon
 function wagon:init_new_instance(train_id, properties)
@@ -147,6 +149,7 @@ end
 
 -- Remove the wagon
 function wagon:on_punch(puncher, time_from_last_punch, tool_capabilities, direction)
+return advtrains.pcall(function()
 	if not self:ensure_init() then return end
 	if not puncher or not puncher:is_player() then
 		return
@@ -177,6 +180,7 @@ function wagon:on_punch(puncher, time_from_last_punch, tool_capabilities, direct
 			inv:add_item("main", item)
 		end
 	end
+end)
 end
 function wagon:destroy()
 	--some rules:
@@ -211,6 +215,8 @@ end
 
 
 function wagon:on_step(dtime)
+return advtrains.pcall(function()
+
 	if not self:ensure_init() then return end
 	
 	local t=os.clock()
@@ -465,6 +471,7 @@ function wagon:on_step(dtime)
 	self.old_acceleration_vector=accelerationvec
 	self.old_yaw=yaw
 	atprintbm("wagon step", t)
+end)
 end
 
 function advtrains.get_real_path_index(train, pit)
@@ -485,6 +492,8 @@ function advtrains.get_real_path_index(train, pit)
 end
 
 function wagon:on_rightclick(clicker)
+return advtrains.pcall(function()
+
 	if not self:ensure_init() then return end
 	if not clicker or not clicker:is_player() then
 		return
@@ -564,6 +573,7 @@ function wagon:on_rightclick(clicker)
 			self:show_get_on_form(pname)
 		end
 	end
+end)
 end
 
 function wagon:get_on(clicker, seatno)
@@ -708,6 +718,8 @@ function wagon:show_wagon_properties(pname)
 	minetest.show_formspec(pname, "advtrains_prop_"..self.unique_id, form)
 end
 minetest.register_on_player_receive_fields(function(player, formname, fields)
+return advtrains.pcall(function()
+
 	local uid=string.match(formname, "^advtrains_geton_(.+)$")
 	if uid then
 		for _,wagon in pairs(minetest.luaentities) do
@@ -780,6 +792,7 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 		end
 	end
 end)
+end)
 function wagon:seating_from_key_helper(pname, fields, no)
 	local sgr=self.seats[no].group
 	for _,access in ipairs(self.seat_groups[sgr].access_to) do
@@ -841,6 +854,7 @@ function advtrains.register_wagon(sysname, prototype, desc, inv_img)
 		stack_max = 1,
 		
 		on_place = function(itemstack, placer, pointed_thing)
+			return advtrains.pcall(function()
 			if not pointed_thing.type == "node" then
 				return
 			end
@@ -876,6 +890,7 @@ function advtrains.register_wagon(sysname, prototype, desc, inv_img)
 			end
 			return itemstack
 			
+		end)
 		end,
 	})
 end

advtrains/advtrains_luaautomation/interrupt.lua

@@ -22,6 +22,8 @@ function iq.add(t, pos, evtdata)
 end
 
 minetest.register_globalstep(function(dtime)
+return advtrains.pcall(function()
+
 	if run then
 		timer=timer + math.min(dtime, 0.2)
 		for i=1,#queue do
@@ -42,6 +44,7 @@ minetest.register_globalstep(function(dtime)
 		end
 	end
 end)
+end)