From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: BillyGalbreath <blake.galbreath@gmail.com>
Date: Sat, 1 Jan 2022 18:38:58 -0600
Subject: [PATCH] Configurable valid characters for usernames


diff --git a/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java
index 03eb7933f309b30fa8c243f4dd0a292b850bfda0..00a5731e7b1e2b84453e6d1416dce8bd9e1b1b10 100644
--- a/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java
+++ b/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java
@@ -233,6 +233,8 @@ public class ServerLoginPacketListenerImpl implements ServerLoginPacketListener
             return false;
         }
 
+        if (true) return org.purpurmc.purpur.PurpurConfig.usernameValidCharactersPattern.matcher(in).matches(); // Purpur
+
         for (int i = 0, len = in.length(); i < len; ++i) {
             char c = in.charAt(i);
 
diff --git a/src/main/java/org/purpurmc/purpur/PurpurConfig.java b/src/main/java/org/purpurmc/purpur/PurpurConfig.java
index 3462a34a7d8e2bbf4c19c02a0b9f19ad5ccdc00f..73b4aeb50ba60e5708bca6a7762b8c44be9c9287 100644
--- a/src/main/java/org/purpurmc/purpur/PurpurConfig.java
+++ b/src/main/java/org/purpurmc/purpur/PurpurConfig.java
@@ -427,4 +427,11 @@ public class PurpurConfig {
     private static void networkSettings() {
         useUPnP = getBoolean("settings.network.upnp-port-forwarding", useUPnP);
     }
+
+    public static java.util.regex.Pattern usernameValidCharactersPattern;
+    private static void usernameValidationSettings() {
+        String defaultPattern = "^[a-zA-Z0-9_.]*$";
+        String setPattern = getString("settings.username-valid-characters", defaultPattern);
+        usernameValidCharactersPattern = java.util.regex.Pattern.compile(setPattern == null || setPattern.isBlank() ? defaultPattern : setPattern);
+    }
 }