refactor(esplora): in debug build assert that latest_blocks is not empty

Author: ValuedMammal

crates/esplora/src/async_ext.rs

@@ -205,10 +205,16 @@ async fn fetch_block<S: Sleeper>(
 
     // We avoid fetching blocks higher than previously fetched `latest_blocks` as the local chain
     // tip is used to signal for the last-synced-up-to-height.
-    if let Some(tip_height) = latest_blocks.keys().last().copied() {
-        if height > tip_height {
+    match latest_blocks.keys().last().copied() {
+        None => {
+            debug_assert!(false, "`latest_blocks` should not be empty");
             return Ok(None);
         }
+        Some(tip_height) => {
+            if height > tip_height {
+                return Ok(None);
+            }
+        }
     }
 
     Ok(Some(client.get_block_hash(height).await?))

crates/esplora/src/blocking_ext.rs

@@ -190,10 +190,16 @@ fn fetch_block(
 
     // We avoid fetching blocks higher than previously fetched `latest_blocks` as the local chain
     // tip is used to signal for the last-synced-up-to-height.
-    if let Some(tip_height) = latest_blocks.keys().last().copied() {
-        if height > tip_height {
+    match latest_blocks.keys().last().copied() {
+        None => {
+            debug_assert!(false, "`latest_blocks` should not be empty");
             return Ok(None);
         }
+        Some(tip_height) => {
+            if height > tip_height {
+                return Ok(None);
+            }
+        }
     }
 
     Ok(Some(client.get_block_hash(height)?))