Fix possible crash after player left

API.md

@@ -95,8 +95,7 @@ the HUD bar will be initially be shown to the player.
 * `start_hidden`: Whether the HUD bar is initially hidden. This is optional, `default_start_hidden` of the registration function will be used as default
 
 #### Return value
-Always `nil`.
-
+`true` on success, `false` otherwise.
 
 
 ## Modifying a HUD bar
@@ -135,7 +134,7 @@ such network optimization for the “styling” parameters, so keep this in mind
 * `new_text_color`: A 3-octet number defining the new color of the text.
 
 #### Return value
-Always `nil`.
+`true` on success, `false` otherwise.
 
 
 ## Hiding and unhiding a HUD bar
@@ -156,7 +155,7 @@ Hides the specified HUD bar from the screen of the specified player.
 * `identifier`: The identifier of the HUD bar type to hide, as specified in `hb.register_hudbar`.
 
 #### Return value
-Always `nil`.
+`true` on success, `false` otherwise.
 
 
 ### `hb.unhide_hudbar(player, identifier)`
@@ -167,7 +166,7 @@ Makes a previously hidden HUD bar visible again to a player.
 * `identifier`: The identifier of the HUD bar type to unhide, as specified in `hb.register_hudbar`.
 
 #### Return value
-Always `nil`.
+`true` on success, `false` otherwise.
 
 
 ## Reading HUD bar information
@@ -181,12 +180,14 @@ Returns the current state of the active player's HUD bar.
 * `identifier`: The identifier of the HUD bar type to hide, as specified in `hb.register_hudbar`.
 
 #### Return value
-A table which holds information on the current state of the HUD bar. Note the table is a deep
-copy of the internal HUD bar state, it is *not* a reference; the information hold by the table is
-only true for the moment you called this function. The fields of this table are:
+On success, returns a table which holds information on the current state of the HUD bar. Note
+the table is a deep copy of the internal HUD bar state, it is *not* a reference; the information
+hold by the table is only true for the moment you called this function. The fields of this table are:
 
 * `value`: Current value of HUD bar.
 * `max`: Current maximum value of HUD bar.
 * `hidden`: Boolean denoting whether the HUD bar is hidden.
 * `barlength`: The length of the HUD bar in pixels. This field is meaningless if the HUD bar is currently hidden.
 * `text`: The text shown on the HUD bar. This fiels is meaningless if the HUD bar is currently hidden.
+
+If the player does not exist, returns `nil` instead.

init.lua

@@ -90,6 +90,10 @@ else
 	hb.settings.sorting_reverse = { [0] = "health", [1] = "breath" }
 end
 
+local function player_exists(player)
+	return player ~= nil and player:is_player()
+end
+
 -- Table which contains all players with active default HUD bars (only for internal use)
 hb.players = {}
 
@@ -285,13 +289,18 @@ function hb.register_hudbar(identifier, text_color, label, textures, default_sta
 end
 
 function hb.init_hudbar(player, identifier, start_value, start_max, start_hidden)
+	if not player_exists(player) then return false end
 	local hudtable = hb.get_hudtable(identifier)
 	hb.hudtables[identifier].add_all(player, hudtable, start_value, start_max, start_hidden)
+	return true
 end
 
 function hb.change_hudbar(player, identifier, new_value, new_max_value, new_icon, new_bgicon, new_bar, new_label, new_text_color)
 	if new_value == nil and new_max_value == nil and new_icon == nil and new_bgicon == nil and new_bar == nil and new_label == nil and new_text_color == nil then
-		return
+		return true
+	end
+	if not player_exists(player) then
+		return false
 	end
 
 	local name = player:get_player_name()
@@ -379,11 +388,14 @@ function hb.change_hudbar(player, identifier, new_value, new_max_value, new_icon
 			end
 		end
 	end
+	return true
 end
 
 function hb.hide_hudbar(player, identifier)
+	if not player_exists(player) then return false end
 	local name = player:get_player_name()
 	local hudtable = hb.get_hudtable(identifier)
+	if hudtable == nil then return false end
 	if(hudtable.hudstate[name].hidden == false) then
 		if hb.settings.bar_type == "progress_bar" then
 			if hudtable.hudids[name].icon ~= nil then
@@ -397,11 +409,14 @@ function hb.hide_hudbar(player, identifier)
 		player:hud_change(hudtable.hudids[name].bar, "number", 0)
 		hudtable.hudstate[name].hidden = true
 	end
+	return true
 end
 
 function hb.unhide_hudbar(player, identifier)
+	if not player_exists(player) then return false end
 	local name = player:get_player_name()
 	local hudtable = hb.get_hudtable(identifier)
+	if hudtable == nil then return false end
 	if(hudtable.hudstate[name].hidden) then
 		local value = hudtable.hudstate[name].value
 		local max = hudtable.hudstate[name].max
@@ -419,9 +434,11 @@ function hb.unhide_hudbar(player, identifier)
 		player:hud_change(hudtable.hudids[name].bar, "number", hb.value_to_barlength(value, max))
 		hudtable.hudstate[name].hidden = false
 	end
+	return true
 end
 
 function hb.get_hudbar_state(player, identifier)
+	if not player_exists(player) then return nil end
 	local ref = hb.get_hudtable(identifier).hudstate[player:get_player_name()]
 	-- Do not forget to update this chunk of code in case the state changes
 	local copy = {
@@ -467,6 +484,7 @@ end
 
 -- update built-in HUD bars
 local function update_hud(player)
+	if not player_exists() then return end
 	if minetest.setting_getbool("enable_damage") then
 		if hb.settings.forceload_default_hudbars then
 			hb.unhide_hudbar(player, "health")
@@ -510,7 +528,8 @@ minetest.register_globalstep(function(dtime)
 		if minetest.setting_getbool("enable_damage") or hb.settings.forceload_default_hudbars then
 			for _, player in pairs(hb.players) do
 				-- update all hud elements
-				update_hud(player)
+minetest.after(1,function(player) update_hud(player) end, player)
+--				update_hud(player)
 			end
 		end
 	end