fix client crash when accessing messenger

src/main/java/carpet/mixins/ClientPlayerEntity_clientCommandMixin.java

@@ -13,7 +13,8 @@ public class ClientPlayerEntity_clientCommandMixin
     @Inject(method = "sendChatMessage", at = @At("HEAD"))
     private void inspectMessage(String string, CallbackInfo ci)
     {
+        ClientPlayerEntity playerSource = (ClientPlayerEntity)(Object) this;
         if (CarpetServer.minecraft_server == null)
-            CarpetServer.settingsManager.inspectClientsideCommand(string);
+            CarpetServer.settingsManager.inspectClientsideCommand(playerSource.getCommandSource(), string);
     }
 }

src/main/java/carpet/settings/SettingsManager.java

@@ -570,7 +570,7 @@ public class SettingsManager
         return 1;
     }
 
-    public void inspectClientsideCommand(String string)
+    public void inspectClientsideCommand(ServerCommandSource source, String string)
     {
         if (string.startsWith("/carpet "))
         {
@@ -581,7 +581,7 @@ public class SettingsManager
                 String strOption = res[2];
                 if (rules.containsKey(setting) && rules.get(setting).isClient)
                 {
-                    rules.get(setting).set(null, strOption);
+                    rules.get(setting).set(source, strOption);
                 }
             }
 

src/main/java/carpet/utils/Messenger.java

@@ -231,7 +231,7 @@ public class Messenger
     //message source
     public static void m(ServerCommandSource source, Object ... fields)
     {
-        source.sendFeedback(Messenger.c(fields),source.getMinecraftServer().getWorld(DimensionType.OVERWORLD) != null);
+        source.sendFeedback(Messenger.c(fields),source.getMinecraftServer() != null && source.getMinecraftServer().getWorld(DimensionType.OVERWORLD) != null);
     }
     public static void m(PlayerEntity player, Object ... fields)
     {