Reorder execution proof gossip checks

Author: frisitano

specs/_features/eip8025/p2p-interface.md

@@ -93,13 +93,31 @@ def validate_execution_proof_gossip(
     Raises GossipIgnore or GossipReject on validation failure.
     """
     proof_envelope = signed_proof_envelope.message
+
+    # [REJECT] The proof data is non-empty
+    if len(proof_envelope.proof_data) == 0:
+        raise GossipReject("execution proof envelope is invalid")
+
+    # [REJECT] The proof type is supported
+    if proof_envelope.proof_type not in get_supported_proof_types():
+        raise GossipReject("execution proof envelope is invalid")
+
     beacon_block_root = proof_envelope.beacon_block_root
+
+    # [IGNORE] The proof's beacon block has been seen
+    if beacon_block_root not in store.blocks:
+        raise GossipIgnore("execution proof's beacon block has not been seen")
+
     proof_root = hash_tree_root(proof_envelope)
 
     # [IGNORE] The proof has not already been processed
     if proof_root in seen.execution_proof_roots.get(beacon_block_root, set()):
         raise GossipIgnore("execution proof has already been processed")
 
+    # [IGNORE] No valid proof is known for this beacon block and proof type
+    if proof_envelope.proof_type in store.execution_proofs.get(beacon_block_root, {}):
+        raise GossipIgnore("verified proof already known for this beacon block and proof type")
+
     # [IGNORE] This is the prover's first valid or invalid proof for this key
     validator_index = signed_proof_envelope.validator_index
     prover_key = (beacon_block_root, proof_envelope.proof_type, validator_index)
@@ -108,20 +126,12 @@ def validate_execution_proof_gossip(
             "proof already seen from this prover for this beacon block and proof type"
         )
 
-    # [IGNORE] The proof's beacon block has been seen
-    if beacon_block_root not in store.blocks:
-        raise GossipIgnore("execution proof's beacon block has not been seen")
-
     # [IGNORE] The proof's execution payload is available
     if beacon_block_root not in store.payloads:
         raise GossipIgnore("execution proof's payload is unavailable")
 
     payload_envelope = store.payloads[beacon_block_root]
 
-    # [IGNORE] No valid proof is known for this beacon block and proof type
-    if proof_envelope.proof_type in store.execution_proofs.get(beacon_block_root, {}):
-        raise GossipIgnore("verified proof already known for this beacon block and proof type")
-
     # [REJECT] The execution proof envelope passes validation
     state = store.block_states[beacon_block_root]
     try:

tests/core/pyspec/eth_consensus_specs/test/eip8025/unittests/test_gossip_execution_proof.py

@@ -185,6 +185,67 @@ def test_gossip_handles_missing_execution_proof_block_context(spec, state):
     store.payloads[block_root] = payload
 
 
+@with_eip8025_and_later
+@spec_state_test
+def test_gossip_applies_cheap_checks_before_payload_lookup(spec, state):
+    """
+    Apply message-local and deduplication checks before requiring the payload.
+    """
+    store, block_root = setup_store_with_block(spec, state)
+    signed_proof = make_signed_execution_proof_envelope(spec, state, block_root)
+    store.payloads.pop(block_root)
+
+    # Reject message-local structural failures without block or payload context.
+    unknown_root = spec.Root(b"\xaa" * 32)
+    empty_proof = make_signed_execution_proof_envelope(spec, state, unknown_root, proof_data=b"")
+    assert validate(spec, get_seen(spec), store, empty_proof) == (
+        "reject",
+        "execution proof envelope is invalid",
+    )
+    unsupported_proof = make_signed_execution_proof_envelope(
+        spec, state, unknown_root, proof_type=UNSUPPORTED_LOW_PROOF_TYPE
+    )
+    assert validate(spec, get_seen(spec), store, unsupported_proof) == (
+        "reject",
+        "execution proof envelope is invalid",
+    )
+
+    # Ignore known duplicates without requiring the payload.
+    proof_root = signed_proof.message.hash_tree_root()
+    seen = get_seen(spec)
+    seen.execution_proof_roots[block_root] = {proof_root}
+    assert validate(spec, seen, store, signed_proof) == (
+        "ignore",
+        "execution proof has already been processed",
+    )
+
+    store.execution_proofs[block_root] = {signed_proof.message.proof_type: signed_proof.message}
+    assert validate(spec, get_seen(spec), store, signed_proof) == (
+        "ignore",
+        "verified proof already known for this beacon block and proof type",
+    )
+    store.execution_proofs.pop(block_root)
+
+    seen = get_seen(spec)
+    seen.execution_proof_provers.add(
+        (
+            block_root,
+            signed_proof.message.proof_type,
+            signed_proof.validator_index,
+        )
+    )
+    assert validate(spec, seen, store, signed_proof) == (
+        "ignore",
+        "proof already seen from this prover for this beacon block and proof type",
+    )
+
+    # A supported, unseen proof still requires the payload.
+    assert validate(spec, get_seen(spec), store, signed_proof) == (
+        "ignore",
+        "execution proof's payload is unavailable",
+    )
+
+
 @with_eip8025_and_later
 @spec_state_test
 @always_bls