diff --git a/pageserver/src/tenant.rs b/pageserver/src/tenant.rs
index 259fd25e6c8b1..cb3ca9c8b9bc6 100644
--- a/pageserver/src/tenant.rs
+++ b/pageserver/src/tenant.rs
@@ -7341,7 +7341,8 @@ mod tests {
 
     #[tokio::test]
     async fn test_simple_bottom_most_compaction_with_retain_lsns() -> anyhow::Result<()> {
-        let harness = TenantHarness::create("test_simple_bottom_most_compaction_with_retain_lsns").await?;
+        let harness =
+            TenantHarness::create("test_simple_bottom_most_compaction_with_retain_lsns").await?;
         let (tenant, ctx) = harness.load().await;
 
         fn get_key(id: u32) -> Key {
diff --git a/pageserver/src/tenant/timeline/compaction.rs b/pageserver/src/tenant/timeline/compaction.rs
index b1383a105eb5c..82b7845fde206 100644
--- a/pageserver/src/tenant/timeline/compaction.rs
+++ b/pageserver/src/tenant/timeline/compaction.rs
@@ -1281,7 +1281,11 @@ impl Timeline {
         if cfg!(debug_assertions) {
             assert_eq!(
                 lowest_retain_lsn,
-                *retain_lsns_below_horizon.iter().min().unwrap()
+                *retain_lsns_below_horizon
+                    .iter()
+                    .min()
+                    .copied()
+                    .unwrap_or(gc_cutoff)
             );
         }
         info!(