From 367f39db90da35c2fa879a0d5470fb7b848c8e0d Mon Sep 17 00:00:00 2001
From: Judd Keppel <kepzorz@gmail.com>
Date: Tue, 13 Feb 2024 16:02:57 -0600
Subject: [PATCH] Handle signer checkpoint interval check case where index is 0

---
 src/bitcoin/signer.rs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/bitcoin/signer.rs b/src/bitcoin/signer.rs
index 8b220b7d..05eb9d7a 100644
--- a/src/bitcoin/signer.rs
+++ b/src/bitcoin/signer.rs
@@ -363,7 +363,11 @@ where
             let last_signed_btc_height: Option<u64> = self
                 .client()
                 .query(|app: InnerApp| {
-                    Ok(app.bitcoin.checkpoints.get(index - 1)?.signed_at_btc_height)
+                    Ok(app
+                        .bitcoin
+                        .checkpoints
+                        .get(index.saturating_sub(1))?
+                        .signed_at_btc_height)
                 })
                 .await?
                 .map(|v| v as u64);