Fixed #971

core/src/io/anuke/mindustry/io/TypeIO.java

@@ -180,15 +180,13 @@ public class TypeIO{
         byte[] bytes = string.getBytes(charset);
         buffer.putInt(bytes.length);
         buffer.put(bytes);
-
-        writeString(buffer, JsonIO.write(rules));
     }
 
     @ReadClass(Rules.class)
     public static Rules readRules(ByteBuffer buffer){
         int length = buffer.getInt();
         byte[] bytes = new byte[length];
-        buffer.get(length);
+        buffer.get(bytes);
         String string = new String(bytes, charset);
         return JsonIO.read(Rules.class, string);
     }

tests/src/test/java/IOTests.java

@@ -1,3 +1,4 @@
+import io.anuke.mindustry.game.*;
 import io.anuke.mindustry.io.TypeIO;
 import org.junit.jupiter.api.Test;
 
@@ -32,4 +33,21 @@ public class IOTests{
         assertNull(TypeIO.readString(buffer));
     }
 
+    @Test
+    void writeRules(){
+        ByteBuffer buffer = ByteBuffer.allocate(500);
+
+        Rules rules = new Rules();
+        rules.attackMode = true;
+        rules.buildSpeedMultiplier = 99f;
+
+        TypeIO.writeRules(buffer, rules);
+        buffer.position(0);
+        Rules res = TypeIO.readRules(buffer);
+
+        assertEquals(rules.buildSpeedMultiplier, res.buildSpeedMultiplier);
+        assertEquals(rules.attackMode, res.attackMode);
+    }
+
+
 }