Fix: prevent a single fire command from spawning duplicate bullets with the same ID

robocode.battle/src/main/java/net/sf/robocode/battle/peer/RobotPeer.java

@@ -856,6 +856,12 @@ private void fireBullets(List<BulletCommand> bulletCommands) {
 				println("SYSTEM: You cannot call fire(NaN)");
 				continue;
 			}
+			// Skip commands that have already fired: the command list is shared
+			// across turns, so a robot that stops executing would otherwise
+			// re-fire the same command (and its bullet id) on every cooldown.
+			if (bulletCmd.isConsumed()) {
+				continue;
+			}
 			if (gunHeat > 0 || energy == 0) {
 				return;
 			}
@@ -877,6 +883,9 @@ private void fireBullets(List<BulletCommand> bulletCommands) {
 			}
 			newBullet.setX(x);
 			newBullet.setY(y);
+
+			// Mark consumed so this command cannot fire again on a later cooldown.
+			bulletCmd.consume();
 		}
 		// there is only last bullet in one turn
 		if (newBullet != null) {

robocode.core/src/main/java/net/sf/robocode/peer/BulletCommand.java

@@ -33,6 +33,19 @@ public BulletCommand(double power, boolean fireAssistValid, double fireAssistAng
 	private final double fireAssistAngle;
 	private final int bulletId;
 
+	// Battle-side only: marks that this command has already fired a bullet, so it
+	// is not fired again on a later cooldown when the command list persists across
+	// turns (e.g. after the robot stops executing). Not part of the wire format.
+	private transient boolean consumed;
+
+	public boolean isConsumed() {
+		return consumed;
+	}
+
+	public void consume() {
+		consumed = true;
+	}
+
 	public boolean isFireAssistValid() {
 		return fireAssistValid;
 	}