From 64096246ef5689f797bfc54e568c4e55e345617a Mon Sep 17 00:00:00 2001
From: Keyvan Kambakhsh <keyvankambakhsh@gmail.com>
Date: Wed, 6 Sep 2023 20:18:06 +0330
Subject: [PATCH] Median returns None in case of empty lists

---
 src/node/heartbeat/sync_clock.rs | 5 +++--
 src/utils/mod.rs                 | 8 ++++++--
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/node/heartbeat/sync_clock.rs b/src/node/heartbeat/sync_clock.rs
index a202978d..a58a20b5 100644
--- a/src/node/heartbeat/sync_clock.rs
+++ b/src/node/heartbeat/sync_clock.rs
@@ -53,8 +53,9 @@ pub async fn sync_clock<K: KvStore, B: Blockchain<K>>(
             .unzip();
         if !timestamps.is_empty() {
             // Set timestamp_offset according to median timestamp of the network
-            let median_timestamp = utils::median(&timestamps);
-            let median_timestamp_offset = utils::median(&timestamp_offsets);
+            let median_timestamp = utils::median(&timestamps).expect("Timestamp list not empty!");
+            let median_timestamp_offset =
+                utils::median(&timestamp_offsets).expect("Timestamp list not empty!");
             ctx.timestamp_offset = median_timestamp as i32 - utils::local_timestamp() as i32;
             ctx.timestamp_offset -= median_timestamp_offset;
         }
diff --git a/src/utils/mod.rs b/src/utils/mod.rs
index 834b834b..0642c109 100644
--- a/src/utils/mod.rs
+++ b/src/utils/mod.rs
@@ -7,8 +7,12 @@ pub fn local_timestamp() -> u32 {
         .as_secs() as u32
 }
 
-pub fn median<T: Clone + std::cmp::Ord>(inps: &[T]) -> T {
+pub fn median<T: Clone + std::cmp::Ord>(inps: &[T]) -> Option<T> {
     let mut sorted = inps.to_vec();
     sorted.sort();
-    sorted[sorted.len() / 2].clone()
+    if sorted.len() > 0 {
+        Some(sorted[sorted.len() / 2].clone())
+    } else {
+        None
+    }
 }