Fix inventory_sync player created/removed

Create entries for players that are present in the save on server
startup to preserving their inventory and fix attempting to reference the
player object after it had been removed in on_player_removed.

plugins/inventory_sync/module/inventory_sync.lua

@@ -19,6 +19,24 @@ local handle_gui_events = require("modules/inventory_sync/gui/handle_gui_events"
 local dialog_failed_download = require("modules/inventory_sync/gui/dialog_failed_download")
 local clean_dirty_inventory = require("modules/inventory_sync/script/clean_dirty_inventory")
 
+
+local function create_player(player, dirty)
+	global.inventory_sync.players[player.name] = {
+		dirty_inventory = dirty, -- Player has a temporary non-synced inventory that should be persisted
+		sync_start_tick = 0, -- To track download failure timeout
+	}
+end
+
+local function remove_player(player)
+	-- Remove inventory download performance counter
+	global.inventory_sync.download_start_tick[player.name] = nil
+	-- Remove stored crafting queue
+	global.inventory_sync.saved_crafting_queue[player.name] = nil
+	-- Remove other player data
+	global.inventory_sync.players[player.name] = nil
+end
+
+
 inventory_sync = {}
 inventory_sync.welcome_new_player = welcome_new_player
 -- This function is called by instance.js as /sc inventory_sync.download_inventory("danielv", Escaped JSON string, package_number, total_packages_count) with data from the master
@@ -48,26 +66,21 @@ inventory_sync.events[clusterio_api.events.on_server_startup] = function(event)
 	if not global.inventory_sync.players then
 		global.inventory_sync.players = {}
 	end
+
+	for _, player in pairs(game.players) do
+		if not global.inventory_sync.players[player.name] then
+			create_player(player, true)
+		end
+	end
 end
 
 -- Cleanup
-inventory_sync.events[defines.events.on_player_removed] = function(event)
-	local player = game.get_player(event.player_index)
-
-	-- Remove inventory download performance counter
-	global.inventory_sync.download_start_tick[player.name] = nil
-	-- Remove stored crafting queue
-	global.inventory_sync.saved_crafting_queue[player.name] = nil
-	-- Remove other player data
-	global.inventory_sync.players[player.name] = nil
+inventory_sync.events[defines.events.on_pre_player_removed] = function(event)
+	remove_player(game.get_player(event.player_index))
 end
 
 inventory_sync.events[defines.events.on_player_created] = function(event)
-	local player = game.get_player(event.player_index)
-	global.inventory_sync.players[player.name] = {
-		dirty_inventory = false, -- Player has a temporary non-synced inventory that should be persisted
-		sync_start_tick = 0, -- To track download failure timeout
-	}
+	create_player(game.get_player(event.player_index), false)
 end
 
 inventory_sync.events[defines.events.on_gui_click] = handle_gui_events