From 6b299402184a6c5a65889acf8be97b64b22bf924 Mon Sep 17 00:00:00 2001
From: Marius van der Wijden <m.vanderwijden@live.de>
Date: Mon, 8 Jan 2024 16:16:09 +0100
Subject: [PATCH] eth/catalyst: apply lightclients suggestions moves the
 loopOnDemand outside making it part of the api

---
 eth/catalyst/simulated_beacon.go     | 40 +++++-----------------------
 eth/catalyst/simulated_beacon_api.go | 31 ++++++++++++++++++---
 ethclient/simulated/backend.go       |  3 +--
 3 files changed, 36 insertions(+), 38 deletions(-)

diff --git a/eth/catalyst/simulated_beacon.go b/eth/catalyst/simulated_beacon.go
index 291f91874c..3c081074cc 100644
--- a/eth/catalyst/simulated_beacon.go
+++ b/eth/catalyst/simulated_beacon.go
@@ -19,14 +19,12 @@ package catalyst
 import (
 	"crypto/rand"
 	"errors"
-	"math"
 	"math/big"
 	"sync"
 	"time"
 
 	"github.com/ethereum/go-ethereum/beacon/engine"
 	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/eth"
 	"github.com/ethereum/go-ethereum/log"
@@ -88,7 +86,6 @@ type SimulatedBeacon struct {
 // Period sets the period in which blocks should be produced.
 //
 //   - If period is set to 0, a block is produced on every transaction.
-//   - If period is set to math.MaxUint64, blocks can only be produced
 //     via Commit, Fork and AdjustTime.
 func NewSimulatedBeacon(period uint64, eth *eth.Ethereum) (*SimulatedBeacon, error) {
 	block := eth.BlockChain().CurrentBlock()
@@ -125,9 +122,7 @@ func (c *SimulatedBeacon) setFeeRecipient(feeRecipient common.Address) {
 // Start invokes the SimulatedBeacon life-cycle function in a goroutine.
 func (c *SimulatedBeacon) Start() error {
 	if c.period == 0 {
-		go c.loopOnDemand()
-	} else if c.period == math.MaxUint64 {
-		// if period is set to MaxUint, do not mine at all
+		// if period is set to 0, do not mine at all
 		// this is used in the simulated backend where blocks
 		// are explicitly mined via Commit, AdjustTime and Fork
 	} else {
@@ -204,32 +199,6 @@ func (c *SimulatedBeacon) sealBlock(withdrawals []*types.Withdrawal, timestamp u
 	return nil
 }
 
-// loopOnDemand runs the block production loop for "on-demand" configuration (period = 0)
-func (c *SimulatedBeacon) loopOnDemand() {
-	var (
-		newTxs = make(chan core.NewTxsEvent)
-		sub    = c.eth.TxPool().SubscribeTransactions(newTxs, true)
-	)
-	defer sub.Unsubscribe()
-
-	for {
-		select {
-		case <-c.shutdownCh:
-			return
-		case w := <-c.withdrawals.pending:
-			withdrawals := append(c.withdrawals.gatherPending(9), w)
-			if err := c.sealBlock(withdrawals, uint64(time.Now().Unix())); err != nil {
-				log.Warn("Error performing sealing work", "err", err)
-			}
-		case <-newTxs:
-			withdrawals := c.withdrawals.gatherPending(10)
-			if err := c.sealBlock(withdrawals, uint64(time.Now().Unix())); err != nil {
-				log.Warn("Error performing sealing work", "err", err)
-			}
-		}
-	}
-}
-
 // loop runs the block production loop for non-zero period configuration
 func (c *SimulatedBeacon) loop() {
 	timer := time.NewTimer(0)
@@ -318,10 +287,15 @@ func (c *SimulatedBeacon) AdjustTime(adjustment time.Duration) error {
 }
 
 func RegisterSimulatedBeaconAPIs(stack *node.Node, sim *SimulatedBeacon) {
+	api := &api{sim}
+	if sim.period == 0 {
+		// mine on demand if period is set to 0
+		go api.loop()
+	}
 	stack.RegisterAPIs([]rpc.API{
 		{
 			Namespace: "dev",
-			Service:   &api{sim},
+			Service:   api,
 			Version:   "1.0",
 		},
 	})
diff --git a/eth/catalyst/simulated_beacon_api.go b/eth/catalyst/simulated_beacon_api.go
index 93670257f6..73d0a5921d 100644
--- a/eth/catalyst/simulated_beacon_api.go
+++ b/eth/catalyst/simulated_beacon_api.go
@@ -18,19 +18,44 @@ package catalyst
 
 import (
 	"context"
+	"time"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/log"
 )
 
 type api struct {
-	simBeacon *SimulatedBeacon
+	sim *SimulatedBeacon
+}
+
+func (a *api) loop() {
+	var (
+		newTxs = make(chan core.NewTxsEvent)
+		sub    = a.sim.eth.TxPool().SubscribeTransactions(newTxs, true)
+	)
+	defer sub.Unsubscribe()
+
+	for {
+		select {
+		case <-a.sim.shutdownCh:
+			return
+		case w := <-a.sim.withdrawals.pending:
+			withdrawals := append(a.sim.withdrawals.gatherPending(9), w)
+			if err := a.sim.sealBlock(withdrawals, uint64(time.Now().Unix())); err != nil {
+				log.Warn("Error performing sealing work", "err", err)
+			}
+		case <-newTxs:
+			a.sim.Commit()
+		}
+	}
 }
 
 func (a *api) AddWithdrawal(ctx context.Context, withdrawal *types.Withdrawal) error {
-	return a.simBeacon.withdrawals.add(withdrawal)
+	return a.sim.withdrawals.add(withdrawal)
 }
 
 func (a *api) SetFeeRecipient(ctx context.Context, feeRecipient common.Address) {
-	a.simBeacon.setFeeRecipient(feeRecipient)
+	a.sim.setFeeRecipient(feeRecipient)
 }
diff --git a/ethclient/simulated/backend.go b/ethclient/simulated/backend.go
index 68b69c0aad..aeec973647 100644
--- a/ethclient/simulated/backend.go
+++ b/ethclient/simulated/backend.go
@@ -17,7 +17,6 @@
 package simulated
 
 import (
-	"math"
 	"time"
 
 	"github.com/ethereum/go-ethereum"
@@ -90,7 +89,7 @@ func New(alloc core.GenesisAlloc, gasLimit uint64) *Backend {
 	conf.Genesis = &genesis
 	conf.SyncMode = downloader.FullSync
 	conf.TxPool.NoLocals = true
-	sim, err := newWithNode(stack, &conf, math.MaxUint64)
+	sim, err := newWithNode(stack, &conf, 0)
 	if err != nil {
 		// This should never happen, if it does, please open an issue
 		panic(err)