Fix as per CSV sheet tracking + creature explanation

module/models/weapon.mjs

@@ -13,7 +13,14 @@ export default class MGNEWeapon extends foundry.abstract.TypeDataModel {
       }),
       damage: stringField("1d4"),
       range: stringField("Touch"),
-      properties: stringField(""),
+      properties: new foundry.data.fields.SetField(
+        new foundry.data.fields.StringField({ required: true, nullable: false, blank: false }),
+        { required: true, nullable: false, initial: [] }
+      ),
+      weight: new foundry.data.fields.StringField({
+        required: true, nullable: false, initial: "normal",
+        choices: SYSTEM.weightCategories,
+      }),
       usageDie: new foundry.data.fields.StringField({
         required: true,
         nullable: false,
@@ -23,9 +30,29 @@ export default class MGNEWeapon extends foundry.abstract.TypeDataModel {
       quantity: numberField(1, 0),
       equipped: booleanField(false),
       broken: booleanField(false),
+      durabilityDie: new foundry.data.fields.StringField({
+        required: true, nullable: false, initial: "d6",
+        choices: SYSTEM.usageDieChoices,
+      }),
     }
   }
 
   /** @override */
   static LOCALIZATION_PREFIXES = ["MGNE.Weapon"]
+
+  /**
+   * Migrate old string-based properties field to the new SetField format.
+   * @override
+   */
+  static migrateData(source) {
+    // Old data stored properties as a plain string; convert to empty array
+    if (typeof source.properties === "string") {
+      source.properties = []
+    }
+    // Remove any null/undefined/blank entries that may have crept in
+    if (Array.isArray(source.properties)) {
+      source.properties = source.properties.filter(p => p != null && p !== "")
+    }
+    return super.migrateData(source)
+  }
 }