Fix missing translation warning being printed multiple times

CHANGELOG.md

@@ -7,6 +7,9 @@
 - Variable containing the distance between a player and waypoint for the cost formula (`distance`)
 - Option to hide waypoints that are in different worlds as the player
 
+### Fixed
+- Warning that a world name has not been translated is printed multiple times
+
 ## 4.5.3
 
 ### Added

waypoints/src/main/kotlin/de/md5lukas/waypoints/lang/WorldTranslations.kt

@@ -2,6 +2,7 @@ package de.md5lukas.waypoints.lang
 
 import de.md5lukas.commons.paper.registerEvents
 import de.md5lukas.waypoints.events.ConfigReloadEvent
+import java.util.*
 import net.kyori.adventure.text.Component
 import org.bukkit.World
 import org.bukkit.event.EventHandler
@@ -13,18 +14,18 @@ class WorldTranslations(private val tl: YmlTranslationLoader) : Listener {
     tl.plugin.registerEvents(this)
   }
 
-  private val warned: MutableSet<World> = mutableSetOf()
+  private val warned: MutableSet<World> = Collections.synchronizedSet(mutableSetOf())
 
   fun getWorldName(world: World): Component {
     if (world in warned) return Component.text(world.name)
 
     val key = "worlds.${world.name}"
-    return if (key in tl) {
+    return if (tl.contains(key, false)) {
       Component.text(tl[key])
     } else {
       warned.add(world)
       tl.plugin.slF4JLogger.warn(
-          "The world {} has no translation present. Using actual name as a fallback.", world.name)
+          "The world '{}' has no translation present. Using actual name as a fallback.", world.name)
       Component.text(world.name)
     }
   }

waypoints/src/main/kotlin/de/md5lukas/waypoints/lang/YmlTranslationLoader.kt

@@ -5,6 +5,8 @@ import de.md5lukas.waypoints.WaypointsPlugin
 import de.md5lukas.waypoints.events.ConfigReloadEvent
 import java.io.File
 import java.nio.charset.StandardCharsets
+import java.util.*
+import kotlin.collections.HashMap
 import net.kyori.adventure.text.format.TextDecoration
 import net.kyori.adventure.text.minimessage.MiniMessage
 import net.kyori.adventure.text.minimessage.tag.resolver.TagResolver
@@ -121,11 +123,11 @@ class YmlTranslationLoader(
             "The key $key is not present in the translation file for the language $loadedLanguage")
   }
 
-  private val warned: MutableSet<String> = mutableSetOf()
+  private val warned: MutableSet<String> = Collections.synchronizedSet(mutableSetOf())
 
-  operator fun contains(key: String): Boolean {
+  fun contains(key: String, printWarning: Boolean): Boolean {
     val contains = key in translations
-    if (!contains && key !in warned) {
+    if (printWarning && !contains && key !in warned) {
       plugin.slF4JLogger.warn(
           "The translation key {} is missing in the translation file for the language {}, but not required",
           key,