Add payload to a cache for later signing

beacon_node/http_api/src/produce_block.rs

@@ -140,7 +140,8 @@ pub fn build_response_v4<T: BeaconChainTypes>(
         .to_ref()
         .fork_name(&chain.spec)
         .map_err(inconsistent_fork_rejection)?;
-    let consensus_block_value_wei = Uint256::from(consensus_block_value) * Uint256::from(1_000_000_000u64);
+    let consensus_block_value_wei =
+        Uint256::from(consensus_block_value) * Uint256::from(1_000_000_000u64);
 
     match accept_header {
         Some(api_types::Accept::Ssz) => Response::builder()

beacon_node/http_api/src/validator/mod.rs

@@ -1,4 +1,6 @@
-use crate::produce_block::{produce_blinded_block_v2, produce_block_v2, produce_block_v3, produce_block_v4};
+use crate::produce_block::{
+    produce_blinded_block_v2, produce_block_v2, produce_block_v3, produce_block_v4,
+};
 use crate::task_spawner::{Priority, TaskSpawner};
 use crate::utils::{
     AnyVersionFilter, ChainFilter, EthV1Filter, NetworkTxFilter, NotWhileSyncingFilter,

beacon_node/http_api/tests/tests.rs

@@ -3799,6 +3799,19 @@ impl ApiTester {
             );
             assert!(!metadata.consensus_block_value.is_zero());
 
+            // Verify that the execution payload envelope is cached for local building.
+            // The envelope is stored in the pending cache until publishing.
+            let block_root = block.tree_hash_root();
+            let envelope = self
+                .chain
+                .pending_payload_envelopes
+                .read()
+                .get(&block_root)
+                .cloned()
+                .expect("envelope should exist in pending cache for local building");
+            assert_eq!(envelope.beacon_block_root, block_root);
+            assert_eq!(envelope.slot, slot);
+
             // Sign and publish the block
             let signed_block = block.sign(&sk, &fork, genesis_validators_root, &self.chain.spec);
             let signed_block_request =