fix(core): preserve null gold in DonateGoldExecution constructor (#4092)

src/core/execution/DonateGoldExecution.ts

@@ -18,7 +18,7 @@ import {
 
 export class DonateGoldExecution implements Execution {
   private recipient: Player;
-  private gold: Gold;
+  private gold: Gold | null = null;
 
   private mg: Game;
   private random: PseudoRandom;
@@ -30,7 +30,7 @@ export class DonateGoldExecution implements Execution {
     private recipientID: PlayerID,
     goldNum: number | null,
   ) {
-    this.gold = toInt(goldNum ?? 0);
+    this.gold = goldNum !== null ? toInt(goldNum) : null;
   }
 
   init(mg: Game, ticks: number): void {

tests/Donate.test.ts

@@ -124,6 +124,27 @@ describe("Donate gold to an ally", () => {
     expect(donor.gold() < donorGoldBefore).toBe(true);
     expect(recipient.gold() > recipientGoldBefore).toBe(true);
   });
+
+  it("Gold should default to 1/3 when null is passed", async () => {
+    const game = await setup("ocean_and_land", { infiniteGold: false, donateGold: true });
+    const dInfo = new PlayerInfo("d", PlayerType.Human, null, "d_id");
+    const rInfo = new PlayerInfo("r", PlayerType.Human, null, "r_id");
+    game.addPlayer(dInfo);
+    game.addPlayer(rInfo);
+    const donor = game.player(dInfo.id), recipient = game.player(rInfo.id);
+    game.addExecution(
+      new SpawnExecution("g", dInfo, game.ref(0, 10)),
+      new SpawnExecution("g", rInfo, game.ref(0, 15)),
+    );
+    donor.createAllianceRequest(recipient)?.accept();
+    game.executeNextTick();
+    donor.addGold(9000n);
+    const goldBefore = donor.gold(), recBefore = recipient.gold();
+    game.addExecution(new DonateGoldExecution(donor, rInfo.id, null));
+    game.executeNextTick();
+    game.executeNextTick();
+    expect(recipient.gold() >= recBefore + goldBefore / 3n).toBe(true);
+  });
 });
 
 describe("Donate troops to a non ally", () => {