Check codehash changes synchronously (#251)

Author: hazim-j

pkg/modules/checks/codehash.go

@@ -3,44 +3,26 @@ package checks
 import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/crypto"
-	"golang.org/x/sync/errgroup"
 )
 
 type codeHash struct {
 	Address common.Address `json:"address"`
 	Hash    common.Hash    `json:"hash"`
 }
 
-func getCodeHashAsync(addr common.Address, gc GetCodeFunc, c chan codeHash) func() error {
-	return func() error {
+func getCodeHashes(ic []common.Address, gc GetCodeFunc) ([]codeHash, error) {
+	ret := []codeHash{}
+
+	for _, addr := range ic {
 		bytecode, err := gc(addr)
 		if err != nil {
-			c <- codeHash{}
-			return err
+			return ret, err
 		}
 
-		ch := codeHash{
+		ret = append(ret, codeHash{
 			Address: addr,
 			Hash:    crypto.Keccak256Hash(bytecode),
-		}
-		c <- ch
-		return nil
-	}
-}
-
-func getCodeHashes(ic []common.Address, gc GetCodeFunc) ([]codeHash, error) {
-	g := new(errgroup.Group)
-	c := make(chan codeHash)
-	ret := []codeHash{}
-
-	for _, addr := range ic {
-		g.Go(getCodeHashAsync(addr, gc, c))
-	}
-	for range ic {
-		ret = append(ret, <-c)
-	}
-	if err := g.Wait(); err != nil {
-		return ret, err
+		})
 	}
 
 	return ret, nil

pkg/modules/checks/standalone.go

@@ -4,7 +4,6 @@ package checks
 
 import (
 	"math/big"
-	"sync"
 	"time"
 
 	"github.com/dgraph-io/badger/v3"
@@ -137,32 +136,24 @@ func (s *Standalone) SimulateOp() modules.UserOpHandlerFunc {
 func (s *Standalone) CodeHashes() modules.BatchHandlerFunc {
 	return func(ctx *modules.BatchHandlerCtx) error {
 		gc := getCodeWithEthClient(s.eth)
-		g := new(errgroup.Group)
-		mu := &sync.Mutex{}
-		fn := func(i int, op *userop.UserOperation) func() error {
-			return func() error {
-				chs, err := getSavedCodeHashes(s.db, op.GetUserOpHash(ctx.EntryPoint, ctx.ChainID))
-				if err != nil {
-					return err
-				}
 
-				changed, err := hasCodeHashChanges(chs, gc)
-				if err != nil {
-					return err
-				}
-				if changed {
-					mu.Lock()
-					ctx.MarkOpIndexForRemoval(i)
-					mu.Unlock()
-				}
-				return nil
+		end := len(ctx.Batch) - 1
+		for i := end; i >= 0; i-- {
+			op := ctx.Batch[i]
+			chs, err := getSavedCodeHashes(s.db, op.GetUserOpHash(ctx.EntryPoint, ctx.ChainID))
+			if err != nil {
+				return err
 			}
-		}
 
-		for i, op := range ctx.Batch {
-			g.Go(fn(i, op))
+			changed, err := hasCodeHashChanges(chs, gc)
+			if err != nil {
+				return err
+			}
+			if changed {
+				ctx.MarkOpIndexForRemoval(i)
+			}
 		}
-		return g.Wait()
+		return nil
 	}
 }