From 1fcb244b29467fcdb7972a724a1ace8b94a67eb8 Mon Sep 17 00:00:00 2001
From: David <david@taiko.xyz>
Date: Thu, 8 Jun 2023 14:30:53 +0800
Subject: [PATCH] feat(prover): check if a system proof has already been
 submitted by another system prover (#274)

---
 driver/state/state.go |  6 -----
 metrics/metrics.go    |  2 +-
 pkg/rpc/utils.go      | 57 +++++++++++++++++++++++++++++++++++++++++++
 prover/prover.go      | 18 ++++++++++++++
 4 files changed, 76 insertions(+), 7 deletions(-)

diff --git a/driver/state/state.go b/driver/state/state.go
index 4ae0aaae3..81fd67f75 100644
--- a/driver/state/state.go
+++ b/driver/state/state.go
@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"context"
 	"fmt"
-	"math"
 	"math/big"
 	"sync/atomic"
 
@@ -174,11 +173,6 @@ func (s *State) startSubscriptions(ctx context.Context) {
 				}
 			case e := <-s.blockVerifiedCh:
 				log.Info("📈 Block verified", "blockID", e.Id, "hash", common.Hash(e.BlockHash), "reward", e.Reward)
-				if e.Reward > math.MaxInt64 {
-					metrics.DriverProofRewardGauge.Update(math.MaxInt64)
-				} else {
-					metrics.DriverProofRewardGauge.Update(int64(e.Reward))
-				}
 			case e := <-s.crossChainSynced:
 				// Verify the protocol synced block, check if it exists in
 				// L2 execution engine.
diff --git a/metrics/metrics.go b/metrics/metrics.go
index 025837d94..a534a36e7 100644
--- a/metrics/metrics.go
+++ b/metrics/metrics.go
@@ -21,7 +21,6 @@ var (
 	DriverL1CurrentHeightGauge  = metrics.NewRegisteredGauge("driver/l1Current/height", nil)
 	DriverL2HeadIDGauge         = metrics.NewRegisteredGauge("driver/l2Head/id", nil)
 	DriverL2VerifiedHeightGauge = metrics.NewRegisteredGauge("driver/l2Verified/id", nil)
-	DriverProofRewardGauge      = metrics.NewRegisteredGauge("driver/proofReward", nil)
 
 	// Proposer
 	ProposerProposeEpochCounter    = metrics.NewRegisteredCounter("proposer/epoch", nil)
@@ -43,6 +42,7 @@ var (
 	ProverSentInvalidProofCounter     = metrics.NewRegisteredCounter("prover/proof/invalid/sent", nil)
 	ProverReceivedProposedBlockGauge  = metrics.NewRegisteredGauge("prover/proposed/received", nil)
 	ProverReceivedProvenBlockGauge    = metrics.NewRegisteredGauge("prover/proven/received", nil)
+	ProverProofRewardGauge            = metrics.NewRegisteredGauge("prover/proofReward", nil)
 )
 
 // Serve starts the metrics server on the given address, will be closed when the given
diff --git a/pkg/rpc/utils.go b/pkg/rpc/utils.go
index 6fe9e5337..39b8e0e4c 100644
--- a/pkg/rpc/utils.go
+++ b/pkg/rpc/utils.go
@@ -111,6 +111,63 @@ func GetReceiptsByBlock(ctx context.Context, cli *rpc.Client, block *types.Block
 	return receipts, nil
 }
 
+// NeedNewSystemProof checks whether the L2 block still needs a new system proof.
+func NeedNewSystemProof(ctx context.Context, cli *Client, id *big.Int, realProofSkipSize *big.Int) (bool, error) {
+	if realProofSkipSize == nil || realProofSkipSize.Uint64() <= 1 {
+		return false, nil
+	}
+	if id.Uint64()%realProofSkipSize.Uint64() == 0 {
+		log.Info(
+			"Skipping system block proof",
+			"blockID", id.Uint64(),
+			"skipSize", realProofSkipSize.Uint64(),
+		)
+
+		return false, nil
+	}
+
+	var parent *types.Header
+	if id.Cmp(common.Big1) == 0 {
+		header, err := cli.L2.HeaderByNumber(ctx, common.Big0)
+		if err != nil {
+			return false, err
+		}
+
+		parent = header
+	} else {
+		parentL1Origin, err := cli.WaitL1Origin(ctx, new(big.Int).Sub(id, common.Big1))
+		if err != nil {
+			return false, err
+		}
+
+		if parent, err = cli.L2.HeaderByHash(ctx, parentL1Origin.L2BlockHash); err != nil {
+			return false, err
+		}
+	}
+
+	fc, err := cli.TaikoL1.GetForkChoice(nil, id, parent.Hash(), uint32(parent.GasUsed))
+	if err != nil {
+		if !strings.Contains(encoding.TryParsingCustomError(err).Error(), "L1_FORK_CHOICE_NOT_FOUND") {
+			return false, encoding.TryParsingCustomError(err)
+		}
+
+		return true, nil
+	}
+
+	if fc.Prover == encoding.SystemProverAddress {
+		log.Info(
+			"📬 Block's system proof has already been submitted by another system prover",
+			"blockID", id,
+			"prover", fc.Prover,
+			"provenAt", fc.ProvenAt,
+		)
+
+		return false, nil
+	}
+
+	return true, nil
+}
+
 // NeedNewProof checks whether the L2 block still needs a new proof.
 func NeedNewProof(
 	ctx context.Context,
diff --git a/prover/prover.go b/prover/prover.go
index 0b2c5c585..2717b2c22 100644
--- a/prover/prover.go
+++ b/prover/prover.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"crypto/ecdsa"
 	"fmt"
+	"math"
 	"math/big"
 	"sync"
 	"time"
@@ -386,6 +387,17 @@ func (p *Prover) onBlockProposed(
 			}
 		}
 
+		if p.cfg.SystemProver {
+			needNewSystemProof, err := rpc.NeedNewSystemProof(ctx, p.rpc, event.Id, p.protocolConfigs.RealProofSkipSize)
+			if err != nil {
+				return fmt.Errorf("failed to check whether the L2 block needs a new system proof: %w", err)
+			}
+
+			if !needNewSystemProof {
+				return nil
+			}
+		}
+
 		// Check if the current prover has seen this block ID before, there was probably
 		// a L1 reorg, we need to cancel that reorged block's proof generation task at first.
 		if p.currentBlocksBeingProven[event.Meta.Id] != nil {
@@ -443,6 +455,12 @@ func (p *Prover) submitProofOp(ctx context.Context, proofWithHeader *proofProduc
 // the block being proven if it's verified.
 func (p *Prover) onBlockVerified(ctx context.Context, event *bindings.TaikoL1ClientBlockVerified) error {
 	metrics.ProverLatestVerifiedIDGauge.Update(event.Id.Int64())
+	if event.Reward > math.MaxInt64 {
+		metrics.ProverProofRewardGauge.Update(math.MaxInt64)
+	} else {
+		metrics.ProverProofRewardGauge.Update(int64(event.Reward))
+	}
+
 	p.latestVerifiedL1Height = event.Raw.BlockNumber
 
 	log.Info(