merge queue: checking #10061 on unstable (b1bdd31)

beacon_node/beacon_chain/src/payload_bid_verification/gossip_verified_bid.rs

@@ -432,9 +432,15 @@ impl<E: EthSpec> GossipVerifiedPayloadBid<E> {
 
         // [REJECT] `bid.prev_randao` is the correct RANDAO mix -- i.e. validate that
         // `bid.prev_randao == get_randao_mix(parent_state, get_current_epoch(parent_state))`
-        if signed_bid.message.prev_randao
-            != *head_state.get_randao_mix(current_slot.epoch(E::slots_per_epoch()))?
-        {
+        // TODO: Enable head-parent RANDAO gossip spec coverage:
+        // https://github.com/ethereum/consensus-specs/pull/5645
+        let expected_randao = if bid_parent_block_root == cached_head.head_block_root() {
+            cached_head.head_random()?
+        } else {
+            // Head compatibility also permits a bid on the head's parent.
+            cached_head.parent_random()?
+        };
+        if signed_bid.message.prev_randao != expected_randao {
             return Err(PayloadBidError::InvalidPrevRandao { slot: bid_slot });
         }
 

beacon_node/beacon_chain/src/payload_bid_verification/tests.rs

@@ -1111,6 +1111,42 @@ fn valid_bid_after_empty_genesis_uses_parent_payload_gas_limit() {
     );
 }
 
+#[test]
+fn valid_bid_with_parent_in_previous_epoch() {
+    if !fork_name_from_env().is_some_and(|fork| fork.gloas_enabled()) {
+        return;
+    }
+    let epoch_start = E::slots_per_epoch();
+    for (current_slot, bid_slot) in [
+        (epoch_start - 1, epoch_start),
+        (epoch_start, epoch_start),
+        (epoch_start + 1, epoch_start + 1),
+    ] {
+        let ctx = TestContext::new();
+        ctx.slot_clock.set_slot(current_slot);
+        let slot = Slot::new(bid_slot);
+        seed_preferences(&ctx, slot, Address::ZERO, 30_000_000);
+        let parent_state = &ctx.canonical_head.cached_head().snapshot.beacon_state;
+        let bid = ctx.sign_bid(ExecutionPayloadBid {
+            slot,
+            builder_index: 0,
+            fee_recipient: Address::ZERO,
+            gas_limit: 30_000_000,
+            parent_block_root: ctx.genesis_block_root,
+            parent_block_hash: ctx.execution_parent_hash(),
+            prev_randao: *parent_state
+                .get_randao_mix(parent_state.current_epoch())
+                .unwrap(),
+            ..ExecutionPayloadBid::default()
+        });
+        let result = GossipVerifiedPayloadBid::new(bid, &ctx.gossip_ctx());
+        assert!(
+            result.is_ok(),
+            "clock {current_slot}, bid {bid_slot}: {result:?}"
+        );
+    }
+}
+
 #[test]
 fn two_builders_coexist_in_cache() {
     if !fork_name_from_env().is_some_and(|f| f.gloas_enabled()) {