add luacheck and fix common errors

also fixes https://github.com/pandorabox-io/pandorabox.io/issues/493

.github/workflows/luacheck.yml

@@ -0,0 +1,18 @@
+name: luacheck
+
+on: [push, pull_request]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: apt
+      run: sudo apt-get install -y luarocks
+    - name: luacheck install
+      run: luarocks install --local luacheck
+    - name: luacheck run
+      run: $HOME/.luarocks/bin/luacheck ./

.luacheckrc

@@ -0,0 +1,21 @@
+globals = {
+	"hangglider",
+	"areas"
+}
+
+read_globals = {
+	-- Stdlib
+	string = {fields = {"split", "trim"}},
+	table = {fields = {"copy", "getn"}},
+
+	-- Minetest
+	"minetest",
+	"vector", "ItemStack",
+	"dump", "dump2",
+	"VoxelArea",
+
+	-- deps
+	"wardzones",
+	"minetestd",
+	"player_monoids"
+}

init.lua

@@ -54,7 +54,8 @@
 local HUD_Overlay = true --show glider struts as overlay on HUD
 local debug = false --show debug info in top-center of hud
 local moveModelUp = false
-if tonumber(string.sub(minetest.get_version().string, 1, 1)) and tonumber(string.sub(minetest.get_version().string, 1, 1)) > 4 then
+if tonumber(string.sub(minetest.get_version().string, 1, 1)) and
+	tonumber(string.sub(minetest.get_version().string, 1, 1)) > 4 then
 	moveModelUp = true
 end
 hangglider = {} --Make this global, so other mods can tell if hangglider exists.
@@ -99,7 +100,7 @@ minetest.register_entity("hangglider:airstopper", { --A one-instant entity that
 	end
 })]]
 
-if core.global_exists("areas") then
+if minetest.global_exists("areas") then
 	hangglider.flak = true
 	-- chat command definition essentially copied from areas mod.
 	minetest.register_chatcommand("area_flak",{
@@ -124,14 +125,13 @@ if core.global_exists("areas") then
 	})
 end
 
-if core.global_exists("minetestd") and minetestd.services.physicsctl.enabled then
+if minetest.global_exists("minetestd") and minetestd.services.physicsctl.enabled then
 minetestd.physicsctl.register_physics_effect("hangglider",
 	function(player) -- check
 		return hangglider.use[player:get_player_name()]
 	end,
 	function(phys, player) -- blend
 		local vel_y = player:get_player_velocity().y
-		if debug then player:hud_change(hangglider.debug[pname].id, "text", vel_y..', '..player:get_physics_override().gravity..', '..tostring(hangglider.airbreak[pname])) end
 		phys.gravity = phys.gravity*((vel_y + 3)/20)
 		if vel_y < 0 and vel_y > -3 then
 			phys.speed = (math.abs(vel_y/2) + 0.75)
@@ -149,11 +149,12 @@ hangglider.can_fly = function (pname, pos)
 	if wardzones then
 		local zone = wardzones.getZone(pos)
 		if zone then
-			return (minetest.check_player_privs(pname, {protection_bypass=true}) or wardzones.checkPlayerZoneAccess(pname, zone) or not zone["data"]["no_fly"])
+			return (minetest.check_player_privs(pname, {protection_bypass=true}) or
+				wardzones.checkPlayerZoneAccess(pname, zone) or not zone["data"]["no_fly"])
 		end
 	end
 	if areas and  hangglider.flak then
-		for id, area in pairs(areas:getAreasAtPos(pos)) do
+		for _, area in pairs(areas:getAreasAtPos(pos)) do
 			if area.flak then
 				return false
 			end
@@ -186,7 +187,7 @@ end
 local function remove_physics_override(player, overrides)
     for _, attr in pairs(physics_attrs) do
         if overrides[attr] then
-            if core.global_exists("player_monoids") then
+            if minetest.global_exists("player_monoids") then
                 player_monoids[attr]:del_change(player, "hangglider:glider")
             else
                 player:set_physics_override({[attr] = 1})
@@ -226,14 +227,13 @@ minetest.register_entity("hangglider:glider", {
 								else
 									remove_physics_override(player, {speed=1})
 								end
-								if debug then player:hud_change(hangglider.debug[pname].id, "text", step_v..', '..player:get_physics_override().gravity..', '..tostring(hangglider.airbreak[pname])) end
+								if debug then
+									player:hud_change(hangglider.debug[pname].id, "text", step_v..', '..
+										player:get_physics_override().gravity..', '..tostring(hangglider.airbreak[pname]))
+								end
 								apply_physics_override(player, {gravity=((step_v + 3)/20)})
 							end
-							--[[local vel = player:get_player_velocity()
+						end
-							if debug then player:hud_change(hangglider.debug[pname].id, "text", vel.y..', '..grav..', '..tostring(hangglider.airbreak[pname])) end
-
-							player:set_physics_override({gravity = (vel.y + 2.0)/20})
-						]]end
 					end
 				end
 				if not hangglider.can_fly(pname,pos) then
@@ -321,7 +321,7 @@ minetest.register_tool("hangglider:hangglider", {
 	description = "Glider",
 	inventory_image = "glider_item.png",
 	stack_max=1,
-	on_use = function(itemstack, player, pointed_thing)
+	on_use = function(itemstack, player)
 		if not player then
 			return
 		end
@@ -331,7 +331,6 @@ minetest.register_tool("hangglider:hangglider", {
 			minetest.sound_play("bedsheet", {pos=pos, max_hear_distance = 8, gain = 1.0})
 			if HUD_Overlay then player:hud_change(hangglider.id[pname], "text", "glider_struts.png") end
 			local airbreak = false
-			local vel = player:get_player_velocity().y
 			--[[if vel < -1.5 then  -- engage mid-air, falling fast, so stop but ramp velocity more quickly
 				--hangglider.airbreak[pname] = true
 				airbreak = true
@@ -368,7 +367,10 @@ minetest.register_tool("hangglider:hangglider", {
 minetest.register_craft({
 	type = "shapeless",
 	output = "hangglider:hangglider",
-	recipe = {"default:paper", "default:paper", "default:paper", "default:paper", "hangglider:hangglider", "default:paper", "default:paper", "default:paper", "default:paper"},
+	recipe = {"default:paper", "default:paper", "default:paper",
+		"default:paper", "hangglider:hangglider", "default:paper",
+		"default:paper", "default:paper", "default:paper"
+	},
 })
 
 minetest.register_craft({