Clean up alias handling.

There is no need to print a stacktrace when an alias fails, we do not do
this for normal commands. We also now give error messages when attempting
to register an alias instead of having them just silently not function.

By: Travis Watkins <amaranth@ubuntu.com>

paper-api/src/main/java/org/bukkit/command/FormattedCommandAlias.java

@@ -48,7 +48,6 @@ public class FormattedCommandAlias extends Command {
                 } else {
                     sender.sendMessage(org.bukkit.ChatColor.RED + "An internal error occurred while attempting to perform this command");
                 }
-                Bukkit.getLogger().log(Level.WARNING, "Failed to parse command alias " + commandLabel + ": " + formatString, throwable);
                 return false;
             }
         }

paper-api/src/main/java/org/bukkit/command/SimpleCommandMap.java

@@ -257,6 +257,11 @@ public class SimpleCommandMap implements CommandMap {
         Map<String, String[]> values = server.getCommandAliases();
 
         for (String alias : values.keySet()) {
+            if (alias.contains(":") || alias.contains(" ")) {
+                server.getLogger().warning("Could not register alias " + alias + " because it contains illegal characters");
+                continue;
+            }
+
             String[] commandStrings = values.get(alias);
             List<String> targets = new ArrayList<String>();
             StringBuilder bad = new StringBuilder();
@@ -275,16 +280,17 @@ public class SimpleCommandMap implements CommandMap {
                 }
             }
 
+            if (bad.length() > 0) {
+                server.getLogger().warning("Could not register alias " + alias + " because it contains commands that do not exist: " + bad);
+                continue;
+            }
+
             // We register these as commands so they have absolute priority.
             if (targets.size() > 0) {
                 knownCommands.put(alias.toLowerCase(), new FormattedCommandAlias(alias.toLowerCase(), targets.toArray(new String[targets.size()])));
             } else {
                 knownCommands.remove(alias.toLowerCase());
             }
-
-            if (bad.length() > 0) {
-                server.getLogger().warning("The following command(s) could not be aliased under '" + alias + "' because they do not exist: " + bad);
-            }
         }
     }
 }