Add mock witness generation stable 2.0 (#1440)

* cherry-pick b0ceb0d

* chore: remove logging of index for mock witness generation

* feat: log start and end block number, instead of each block for mock witness

cmd/utils/flags.go

@@ -688,6 +688,11 @@ var (
 		Usage: "Seal the batch immediately when detecting a counter overflow",
 		Value: false,
 	}
+	MockWitnessGeneration = cli.BoolFlag{
+		Name:  "zkevm.mock-witness-generation",
+		Usage: "Mock the witness generation",
+		Value: false,
+	}
 	ACLPrintHistory = cli.IntFlag{
 		Name:  "acl.print-history",
 		Usage: "Number of entries to print from the ACL history on node start up",

eth/ethconfig/config_zkevm.go

@@ -86,6 +86,7 @@ type Zk struct {
 	InfoTreeUpdateInterval         time.Duration
 	BadBatches                     []uint64
 	SealBatchImmediatelyOnOverflow bool
+	MockWitnessGeneration          bool
 }
 
 var DefaultZkConfig = &Zk{}

turbo/cli/default_flags.go

@@ -239,4 +239,5 @@ var DefaultFlags = []cli.Flag{
 	&utils.InfoTreeUpdateInterval,
 	&utils.BadBatches,
 	&utils.SealBatchImmediatelyOnOverflow,
+	&utils.MockWitnessGeneration,
 }

turbo/cli/flags_zkevm.go

@@ -3,9 +3,8 @@ package cli
 import (
 	"fmt"
 	"math"
-
+	"strconv"
 	"strings"
-
 	"time"
 
 	libcommon "github.com/gateway-fm/cdk-erigon-lib/common"
@@ -14,7 +13,6 @@ import (
 	"github.com/ledgerwatch/erigon/zk/sequencer"
 	utils2 "github.com/ledgerwatch/erigon/zk/utils"
 	"github.com/urfave/cli/v2"
-	"strconv"
 )
 
 func ApplyFlagsForZkConfig(ctx *cli.Context, cfg *ethconfig.Config) {
@@ -197,6 +195,7 @@ func ApplyFlagsForZkConfig(ctx *cli.Context, cfg *ethconfig.Config) {
 		InfoTreeUpdateInterval:         ctx.Duration(utils.InfoTreeUpdateInterval.Name),
 		BadBatches:                     badBatches,
 		SealBatchImmediatelyOnOverflow: ctx.Bool(utils.SealBatchImmediatelyOnOverflow.Name),
+		MockWitnessGeneration:          ctx.Bool(utils.MockWitnessGeneration.Name),
 	}
 
 	utils2.EnableTimer(cfg.DebugTimers)

zk/witness/witness.go

@@ -191,6 +191,12 @@ func (g *Generator) generateWitness(tx kv.Tx, ctx context.Context, batchNum uint
 		log.Info("Generating witness timing", "batch", batchNum, "blockFrom", blocks[0].NumberU64(), "blockTo", blocks[len(blocks)-1].NumberU64(), "taken", diff)
 	}()
 
+	areExecutorUrlsEmpty := len(g.zkConfig.ExecutorUrls) == 0 || g.zkConfig.ExecutorUrls[0] == ""
+	shouldGenerateMockWitness := g.zkConfig.MockWitnessGeneration && areExecutorUrlsEmpty
+	if shouldGenerateMockWitness {
+		return g.generateMockWitness(batchNum, blocks, debug)
+	}
+
 	endBlock := blocks[len(blocks)-1].NumberU64()
 	startBlock := blocks[0].NumberU64()
 
@@ -325,7 +331,6 @@ func (g *Generator) generateWitness(tx kv.Tx, ctx context.Context, batchNum uint
 		chainReader := stagedsync.NewChainReaderImpl(g.chainCfg, tx, nil)
 
 		_, err = core.ExecuteBlockEphemerallyZk(g.chainCfg, &vmConfig, getHashFn, engine, block, tds, trieStateWriter, chainReader, nil, hermezDb, &prevStateRoot)
-
 		if err != nil {
 			return nil, err
 		}
@@ -363,3 +368,21 @@ func getWitnessBytes(witness *trie.Witness, debug bool) ([]byte, error) {
 	}
 	return buf.Bytes(), nil
 }
+
+func (g *Generator) generateMockWitness(batchNum uint64, blocks []*eritypes.Block, debug bool) ([]byte, error) {
+	mockWitness := []byte("mockWitness")
+	startBlockNumber := blocks[0].NumberU64()
+	endBlockNumber := blocks[len(blocks)-1].NumberU64()
+
+	if debug {
+		log.Info(
+			"Generated mock witness",
+			"witness", mockWitness,
+			"batch", batchNum,
+			"startBlockNumber", startBlockNumber,
+			"endBlockNumber", endBlockNumber,
+		)
+	}
+
+	return mockWitness, nil
+}