From 6d7d53f2e6c77a031af98f52ec884e570f5b846c Mon Sep 17 00:00:00 2001
From: Stanimal <sdbondi@users.noreply.github.com>
Date: Fri, 17 Jun 2022 14:59:22 +0200
Subject: [PATCH] fix(chain-storage): fetch_chain_headers should return empty
 vec if query is out of range

---
 .../src/grpc/base_node_grpc_server.rs            |  4 ++++
 .../src/chain_storage/blockchain_database.rs     | 16 +++++++++++++---
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/applications/tari_base_node/src/grpc/base_node_grpc_server.rs b/applications/tari_base_node/src/grpc/base_node_grpc_server.rs
index 8c7760ba97..97a0e75a98 100644
--- a/applications/tari_base_node/src/grpc/base_node_grpc_server.rs
+++ b/applications/tari_base_node/src/grpc/base_node_grpc_server.rs
@@ -1945,6 +1945,10 @@ impl tari_rpc::base_node_server::BaseNode for BaseNodeGrpcServer {
                     }
                 }
 
+                if headers.len() < BATCH_SIZE {
+                    break;
+                }
+
                 current_height += BATCH_SIZE + 1;
             }
         });
diff --git a/base_layer/core/src/chain_storage/blockchain_database.rs b/base_layer/core/src/chain_storage/blockchain_database.rs
index 991c07f207..4a6f3232e1 100644
--- a/base_layer/core/src/chain_storage/blockchain_database.rs
+++ b/base_layer/core/src/chain_storage/blockchain_database.rs
@@ -1372,9 +1372,19 @@ pub fn fetch_chain_headers<T: BlockchainBackend>(
         ));
     }
 
-    (start..=end_inclusive)
-        .map(|h| db.fetch_chain_header_by_height(h))
-        .collect()
+    #[allow(clippy::cast_possible_truncation)]
+    let mut headers = Vec::with_capacity((end_inclusive - start) as usize);
+    for h in start..=end_inclusive {
+        match db.fetch_chain_header_by_height(h) {
+            Ok(header) => {
+                headers.push(header);
+            },
+            Err(ChainStorageError::ValueNotFound { .. }) => break,
+            Err(e) => return Err(e),
+        }
+    }
+
+    Ok(headers)
 }
 
 fn insert_headers<T: BlockchainBackend>(db: &mut T, headers: Vec<ChainHeader>) -> Result<(), ChainStorageError> {