feat: add empty payload building support (#2346)

crates/rpc/rpc-engine-api/src/engine_api.rs

@@ -125,11 +125,12 @@ where
     /// Note:
     /// > Client software MAY stop the corresponding build process after serving this call.
     pub async fn get_payload_v1(&self, payload_id: PayloadId) -> EngineApiResult<ExecutionPayload> {
-        self.payload_store
+        Ok(self
+            .payload_store
             .get_payload(payload_id)
             .await
-            .map(|payload| (*payload).clone().into_v1_payload())
-            .ok_or(EngineApiError::UnknownPayload)
+            .ok_or(EngineApiError::UnknownPayload)?
+            .map(|payload| (*payload).clone().into_v1_payload())?)
     }
 
     /// Returns the most recent version of the payload that is available in the corresponding
@@ -143,11 +144,12 @@ where
         &self,
         payload_id: PayloadId,
     ) -> EngineApiResult<ExecutionPayloadEnvelope> {
-        self.payload_store
+        Ok(self
+            .payload_store
             .get_payload(payload_id)
             .await
-            .map(|payload| (*payload).clone().into_v2_payload())
-            .ok_or(EngineApiError::UnknownPayload)
+            .ok_or(EngineApiError::UnknownPayload)?
+            .map(|payload| (*payload).clone().into_v2_payload())?)
     }
 
     /// Called to retrieve execution payload bodies by range.

crates/rpc/rpc-engine-api/src/error.rs

@@ -1,5 +1,6 @@
 use jsonrpsee_types::error::{INTERNAL_ERROR_CODE, INVALID_PARAMS_CODE};
 use reth_beacon_consensus::{BeaconEngineError, BeaconForkChoiceUpdateError};
+use reth_payload_builder::error::PayloadBuilderError;
 use reth_primitives::{H256, U256};
 use thiserror::Error;
 use tokio::sync::{mpsc, oneshot};
@@ -75,6 +76,9 @@ pub enum EngineApiError {
     /// Failed to send message due ot closed channel
     #[error("Closed channel")]
     ChannelClosed,
+    /// Fetching the payload failed
+    #[error(transparent)]
+    GetPayloadError(#[from] PayloadBuilderError),
 }
 
 impl<T> From<mpsc::error::SendError<T>> for EngineApiError {