rpc: emit non-nil LastCommit on Autobahn-routed blocks (CON-256)

sei-tendermint/internal/p2p/giga_router.go

@@ -184,7 +184,7 @@ func (r *GigaRouter) BlockByNumber(ctx context.Context, n atypes.GlobalBlockNumb
 // TODO(autobahn): replace this with a direct read from
 // sei-db/ledger_db/block.BlockDB.GetBlockByHash once a writer is wired into
 // block execution. The data.State-side index can also go away at that point.
-func (r *GigaRouter) BlockByHash(_ context.Context, hash atypes.BlockHeaderHash) (*coretypes.ResultBlock, error) {
+func (r *GigaRouter) BlockByHash(ctx context.Context, hash atypes.BlockHeaderHash) (*coretypes.ResultBlock, error) {
 	opt, err := r.data.GlobalBlockByHash(hash)
 	if err != nil {
 		return nil, fmt.Errorf("data.GlobalBlockByHash: %w", err)
@@ -203,12 +203,20 @@ func (r *GigaRouter) BlockByHash(_ context.Context, hash atypes.BlockHeaderHash)
 
 // translateGlobalBlock converts an Autobahn GlobalBlock to the CometBFT
 // coretypes.ResultBlock shape used by env.Block / env.BlockByHash and
-// downstream evmrpc consumers. Caller must pass a non-nil *GlobalBlock
-// with non-nil Header and Payload — that's the contract data.State
-// guarantees on a successful lookup, and matches how executeBlock
-// dereferences b.Header without a nil-check on the same type. The
-// "no such block" case is rejected at the BlockByHash call site
-// before delegating here.
+// downstream evmrpc consumers. Caller must pass a non-nil *GlobalBlock with
+// non-nil Header and Payload — that's the contract data.State guarantees on
+// a successful lookup, and matches how executeBlock dereferences b.Header
+// without a nil-check on the same type. The "no such block" case is
+// rejected at the BlockByHash call site before delegating here.
+//
+// LastCommit is non-nil with empty Signatures, mirroring executeBlock's
+// FinalizeBlock call which passes an empty abci.CommitInfo. Under Autobahn
+// the committee is fixed by genesis (no validator-set updates), so the
+// application is not in control of jailing — surfacing N "absent sig"
+// entries here would make trace replay's BeginBlock bump missed-block
+// counters and diverge from production. ToReqBeginBlock skips the per-
+// validator loop when Signatures is empty, so empty Votes flow into
+// distribution/slashing on both paths.
 func (r *GigaRouter) translateGlobalBlock(gb *atypes.GlobalBlock) *coretypes.ResultBlock {
 	srcTxs := gb.Payload.Txs()
 	tmTxs := make(types.Txs, len(srcTxs))
@@ -227,7 +235,8 @@ func (r *GigaRouter) translateGlobalBlock(gb *atypes.GlobalBlock) *coretypes.Res
 				Height: utils.Clamp[int64](gb.GlobalNumber),
 				Time:   gb.Timestamp,
 			},
-			Data: types.Data{Txs: tmTxs},
+			Data:       types.Data{Txs: tmTxs},
+			LastCommit: &types.Commit{},
 		},
 	}
 }

sei-tendermint/internal/p2p/giga_router_test.go

@@ -372,6 +372,14 @@ func TestGigaRouter_FinalizeBlocks(t *testing.T) {
 			require.Equal(t, committed, rb.Block.Height, "router[%v].BlockByNumber(%v) height", i, committed)
 			require.NotEmpty(t, rb.BlockID.Hash, "router[%v].BlockByNumber(%v) block hash", i, committed)
 			require.Equal(t, genDoc.ChainID, rb.Block.Header.ChainID, "router[%v].BlockByNumber(%v) chain id", i, committed)
+			// LastCommit is non-nil with empty Signatures — mirrors
+			// executeBlock's FinalizeBlock(DecidedLastCommit: empty)
+			// so trace replay and production both see "no votes" on
+			// the prior block. ToReqBeginBlock skips the per-val loop
+			// when Signatures is empty, so this is also enough to
+			// avoid the OOB deref the original PR was guarding against.
+			require.NotNil(t, rb.Block.LastCommit, "router[%v].BlockByNumber(%v) LastCommit", i, committed)
+			require.Empty(t, rb.Block.LastCommit.Signatures, "router[%v].BlockByNumber(%v) Signatures", i, committed)
 			// Round-trip the just-fetched block hash back through
 			// BlockByHash and assert we get the same ResultBlock back.
 			var hashKey atypes.BlockHeaderHash

sei-tendermint/types/block.go

@@ -251,13 +251,17 @@ func (b *Block) ToProto() (*tmproto.Block, error) {
 
 func (b *Block) ToReqBeginBlock(vals []*Validator) abci.RequestBeginBlock {
 	tmHeader := b.Header.ToProto()
-	votes := make([]abci.VoteInfo, 0, b.LastCommit.Size())
-	for i, val := range vals {
-		commitSig := b.LastCommit.Signatures[i]
-		votes = append(votes, abci.VoteInfo{
-			Validator:       TM2PB.Validator(val),
-			SignedLastBlock: commitSig.BlockIDFlag != BlockIDFlagAbsent,
-		})
+	// b.LastCommit.Signatures is only empty on the trace path.
+	var votes []abci.VoteInfo
+	if len(b.LastCommit.Signatures) > 0 {
+		votes = make([]abci.VoteInfo, 0, b.LastCommit.Size())
+		for i, val := range vals {
+			commitSig := b.LastCommit.Signatures[i]
+			votes = append(votes, abci.VoteInfo{
+				Validator:       TM2PB.Validator(val),
+				SignedLastBlock: commitSig.BlockIDFlag != BlockIDFlagAbsent,
+			})
+		}
 	}
 	abciEvidence := b.Evidence.ToABCI()
 	byzantineValidators := make([]abci.Evidence, 0, len(abciEvidence))