Do not copy profile data if profiles are the same (#10259)

patches/server/0134-Basic-PlayerProfile-API.patch

@@ -16,10 +16,10 @@ public org.bukkit.craftbukkit.profile.CraftPlayerProfile setProperty(Ljava/lang/
 
 diff --git a/src/main/java/com/destroystokyo/paper/profile/CraftPlayerProfile.java b/src/main/java/com/destroystokyo/paper/profile/CraftPlayerProfile.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..daa157eaa021d039f9a092bea0b78f7c1f746e3b
+index 0000000000000000000000000000000000000000..68c99e29450e318d2b6eb83099e3e4012b6f0c01
 --- /dev/null
 +++ b/src/main/java/com/destroystokyo/paper/profile/CraftPlayerProfile.java
-@@ -0,0 +1,409 @@
+@@ -0,0 +1,412 @@
 +package com.destroystokyo.paper.profile;
 +
 +import com.mojang.authlib.yggdrasil.ProfileResult;
@@ -236,7 +236,7 @@ index 0000000000000000000000000000000000000000..daa157eaa021d039f9a092bea0b78f7c
 +                    // if old has it, assume its newer, so overwrite, else use cached if it was set and ours wasn't
 +                    copyProfileProperties(this.profile, profile);
 +                    this.profile = profile;
-+                } else {
++                } else if (profile != this.profile) {
 +                    copyProfileProperties(profile, this.profile);
 +                }
 +            }
@@ -267,6 +267,9 @@ index 0000000000000000000000000000000000000000..daa157eaa021d039f9a092bea0b78f7c
 +    }
 +
 +    private static void copyProfileProperties(GameProfile source, GameProfile target, boolean clearTarget) {
++        if (source == target) {
++            throw new IllegalArgumentException("Source and target profiles are the same (" + source + ")");
++        }
 +        PropertyMap sourceProperties = source.getProperties();
 +        PropertyMap targetProperties = target.getProperties();
 +        if (clearTarget) targetProperties.clear();