From 3632ebda8b61735f95f6b0b822411285260adbe7 Mon Sep 17 00:00:00 2001
From: Camotoy <20743703+Camotoy@users.noreply.github.com>
Date: Fri, 10 Sep 2021 16:32:09 -0400
Subject: [PATCH] Prevent concurrency issues with SkinProvider#requestedSkins

There is a small potential here to return null if containsKey runs before remove and then get is called.
---
 .../main/java/org/geysermc/connector/skin/SkinProvider.java | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/connector/src/main/java/org/geysermc/connector/skin/SkinProvider.java b/connector/src/main/java/org/geysermc/connector/skin/SkinProvider.java
index 4b97ba5fb..ed18f2c22 100644
--- a/connector/src/main/java/org/geysermc/connector/skin/SkinProvider.java
+++ b/connector/src/main/java/org/geysermc/connector/skin/SkinProvider.java
@@ -163,7 +163,11 @@ public class SkinProvider {
 
     public static CompletableFuture<Skin> requestSkin(UUID playerId, String textureUrl, boolean newThread) {
         if (textureUrl == null || textureUrl.isEmpty()) return CompletableFuture.completedFuture(EMPTY_SKIN);
-        if (requestedSkins.containsKey(textureUrl)) return requestedSkins.get(textureUrl); // already requested
+        CompletableFuture<Skin> requestedSkin = requestedSkins.get(textureUrl);
+        if (requestedSkin != null) {
+            // already requested
+            return requestedSkin;
+        }
 
         Skin cachedSkin = getCachedSkin(textureUrl);
         if (cachedSkin != null) {