fix(protocol): prevent BoardConverter from choking on faulty lines

Author: anarchuser

plugin/src/shared/sc/plugin2021/xstream/BoardConverter.kt

@@ -5,11 +5,16 @@ import com.thoughtworks.xstream.converters.MarshallingContext
 import com.thoughtworks.xstream.converters.UnmarshallingContext
 import com.thoughtworks.xstream.io.HierarchicalStreamReader
 import com.thoughtworks.xstream.io.HierarchicalStreamWriter
+import org.slf4j.LoggerFactory
 import sc.plugin2021.util.Constants
 import sc.plugin2021.Board
 import sc.plugin2021.FieldContent
 
 class BoardConverter: Converter {
+    companion object {
+        val logger = LoggerFactory.getLogger(BoardConverter::class.java)
+    }
+    
     override fun canConvert(type: Class<*>?): Boolean {
         return type == Board::class.java
     }
@@ -36,10 +41,14 @@ class BoardConverter: Converter {
 
         while (reader.hasMoreChildren()) {
             reader.moveDown()
-            val x = reader.getAttribute("x").toInt()
-            val y = reader.getAttribute("y").toInt()
-            val content = FieldContent.valueOf(reader.getAttribute("content"))
-            field[y][x] = content
+            try {
+                val x = reader.getAttribute("x").toInt()
+                val y = reader.getAttribute("y").toInt()
+                val content = FieldContent.valueOf(reader.getAttribute("content"))
+                field[y][x] = content
+            } catch (e: NullPointerException) {
+                logger.warn("Failed to read field")
+            }
             reader.moveUp()
         }