From d0be90012325021be31f9bfa3a0c62e47a9c3e48 Mon Sep 17 00:00:00 2001
From: Tuyen Nguyen <vutuyen2636@gmail.com>
Date: Mon, 14 Aug 2023 15:51:20 +0700
Subject: [PATCH] fix: handle no vote in prune()

---
 packages/fork-choice/src/forkChoice/forkChoice.ts | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/packages/fork-choice/src/forkChoice/forkChoice.ts b/packages/fork-choice/src/forkChoice/forkChoice.ts
index 62a8af368b62..6dda2c639df2 100644
--- a/packages/fork-choice/src/forkChoice/forkChoice.ts
+++ b/packages/fork-choice/src/forkChoice/forkChoice.ts
@@ -672,6 +672,11 @@ export class ForkChoice implements IForkChoice {
     const prunedNodes = this.protoArray.maybePrune(finalizedRoot);
     const prunedCount = prunedNodes.length;
     for (const vote of this.votes) {
+      // validator has never voted
+      if (vote === undefined) {
+        continue;
+      }
+
       if (vote.currentIndex !== null) {
         if (vote.currentIndex >= prunedCount) {
           vote.currentIndex -= prunedCount;
@@ -680,6 +685,7 @@ export class ForkChoice implements IForkChoice {
           vote.currentIndex = null;
         }
       }
+
       if (vote.nextIndex !== null) {
         if (vote.nextIndex >= prunedCount) {
           vote.nextIndex -= prunedCount;