Print a warning message instead of crashing.

We shouldn't prevent a plugin from adding packet listeners just because
the plugin verifier failed.

ProtocolLib/src/main/java/com/comphenix/protocol/injector/PacketFilterManager.java

@@ -85,6 +85,7 @@ public final class PacketFilterManager implements ProtocolManager, ListenerInvok
 	public static final ReportType REPORT_CANNOT_INJECT_PLAYER = new ReportType("Unable to inject player.");
 
 	public static final ReportType REPORT_CANNOT_UNREGISTER_PLUGIN = new ReportType("Unable to handle disabled plugin.");
+	public static final ReportType REPORT_PLUGIN_VERIFIER_ERROR = new ReportType("Verifier error: %s");
 	
 	/**
 	 * Sets the inject hook type. Different types allow for maximum compatibility.
@@ -298,6 +299,7 @@ public final class PacketFilterManager implements ProtocolManager, ListenerInvok
 	 * @param plugin - plugin to check.
 	 */
 	private void printPluginWarnings(Plugin plugin) {
+		try {
 			switch (pluginVerifier.verify(plugin)) {
 				case NO_DEPEND:
 					reporter.reportWarning(this, Report.newBuilder(REPORT_PLUGIN_DEPEND_MISSING).messageParam(plugin.getName()));
@@ -305,6 +307,9 @@ public final class PacketFilterManager implements ProtocolManager, ListenerInvok
 					// Do nothing
 					break;
 			}
+		} catch (IllegalStateException e) {
+			reporter.reportWarning(this, Report.newBuilder(REPORT_PLUGIN_VERIFIER_ERROR).messageParam(e.getMessage()));
+		}
 	}
 	
 	@Override