fix: correct feature handling

This is based on syntax-level understanding of the code, so please
tripple-check. It seems that the old code flipped the order of
if-branches: if the feature is not active at runtime, we should be doing
the same thing as if the features is not enabled at compile time.

Fix the issue by not repeating the code twice and leveraging the
feature-checking macro instead.

chain/chain/src/chain.rs

@@ -38,8 +38,6 @@ use near_primitives::types::{
     NumBlocks, NumShards, ShardId, StateChangesForSplitStates, StateRoot,
 };
 use near_primitives::unwrap_or_return;
-#[cfg(feature = "protocol_feature_block_header_v3")]
-use near_primitives::version::ProtocolFeature;
 use near_primitives::views::{
     ExecutionOutcomeWithIdView, ExecutionStatusView, FinalExecutionOutcomeView,
     FinalExecutionOutcomeWithReceiptView, FinalExecutionStatus, LightClientBlockView,
@@ -387,23 +385,20 @@ impl Chain {
         last_known_hash: &CryptoHash,
     ) -> Result<CryptoHash, Error> {
         let bps = runtime_adapter.get_epoch_block_producers_ordered(&epoch_id, last_known_hash)?;
-        #[cfg(not(feature = "protocol_feature_block_header_v3"))]
-        {
-            let validator_stakes = bps.into_iter().map(|(bp, _)| bp).collect();
-            Chain::compute_collection_hash(validator_stakes)
-        }
-        #[cfg(feature = "protocol_feature_block_header_v3")]
-        {
-            let protocol_version = runtime_adapter.get_epoch_protocol_version(&epoch_id)?;
-            let block_header_v3_version = ProtocolFeature::BlockHeaderV3.protocol_version();
-            if protocol_version < block_header_v3_version {
-                let validator_stakes = bps.into_iter().map(|(bp, _)| bp.into_v1()).collect();
-                Chain::compute_collection_hash(validator_stakes)
-            } else {
+        let protocol_version = runtime_adapter.get_epoch_protocol_version(&epoch_id)?;
+        checked_feature!(
+            "protocol_feature_block_header_v3",
+            BlockHeaderV3,
+            protocol_version,
+            {
                 let validator_stakes = bps.into_iter().map(|(bp, _)| bp).collect();
                 Chain::compute_collection_hash(validator_stakes)
+            },
+            {
+                let validator_stakes = bps.into_iter().map(|(bp, _)| bp.into_v1()).collect();
+                Chain::compute_collection_hash(validator_stakes)
             }
-        }
+        )
     }
 
     /// Creates a light client block for the last final block from perspective of some other block