miner: Interrupt first payload building job

Also added interrupt test.
Had to add sleep to make non-interrupt test work.

miner/payload_building.go

@@ -186,6 +186,10 @@ func (payload *Payload) resolve(onlyFull bool) *engine.ExecutionPayloadEnvelope
 	payload.lock.Lock()
 	defer payload.lock.Unlock()
 
+	// We interrupt any active building block to prevent it from adding more transactions,
+	// and if it is an update, don't attempt to seal the block.
+	payload.interruptBuilding()
+
 	if payload.full == nil && (onlyFull || payload.empty == nil) {
 		select {
 		case <-payload.stop:
@@ -198,6 +202,7 @@ func (payload *Payload) resolve(onlyFull bool) *engine.ExecutionPayloadEnvelope
 		payload.cond.Wait()
 	}
 
+	// Now we can signal the building routine to stop.
 	payload.stopBuilding()
 
 	if payload.full != nil {
@@ -210,14 +215,32 @@ func (payload *Payload) resolve(onlyFull bool) *engine.ExecutionPayloadEnvelope
 	return nil
 }
 
-// stopBuilding sets an interrupt for any potentially ongoing
-// block building process and signals stop to the block updating routine.
+// interruptBuilding sets an interrupt for a potentially ongoing
+// block building process.
+// This will prevent it from adding new transactions to the block, and if it is
+// building an update, the block will also not be sealed, as we would discard
+// the update anyways.
+// interruptBuilding is safe to be called concurrently.
+func (payload *Payload) interruptBuilding() {
+	// Set the interrupt if not interrupted already.
+	// It's ok if it has either already been interrupted by payload resolution earlier,
+	// or by the timeout timer set to commitInterruptTimeout.
+	if payload.interrupt.CompareAndSwap(commitInterruptNone, commitInterruptResolve) {
+		log.Debug("Interrupted payload building.", "id", payload.id)
+	} else {
+		log.Debug("Payload building already interrupted.",
+			"id", payload.id, "interrupt", payload.interrupt.Load())
+	}
+}
+
+// stopBuilding signals to the block updating routine to stop. An ongoing payload
+// building job will still complete. It can be interrupted to stop filling new
+// transactions with interruptBuilding.
 // stopBuilding is safe to be called concurrently.
 func (payload *Payload) stopBuilding() {
 	// Concurrent Resolve calls should only stop once.
 	payload.stopOnce.Do(func() {
-		log.Debug("Interrupt payload building.", "id", payload.id)
-		payload.interrupt.Store(commitInterruptResolve)
+		log.Debug("Stop payload building.", "id", payload.id)
 		close(payload.stop)
 	})
 }

miner/payload_building_test.go

@@ -17,6 +17,7 @@
 package miner
 
 import (
+	"math/big"
 	"reflect"
 	"testing"
 	"time"
@@ -30,18 +31,29 @@ import (
 )
 
 func TestBuildPayload(t *testing.T) {
-	t.Run("with-tx-pool", func(t *testing.T) { testBuildPayload(t, false) })
-	t.Run("no-tx-pool", func(t *testing.T) { testBuildPayload(t, true) })
+	t.Run("no-tx-pool", func(t *testing.T) { testBuildPayload(t, true, false) })
+	// no-tx-pool case with interrupt not interesting because no-tx-pool doesn't run
+	// the builder routine
+	t.Run("with-tx-pool", func(t *testing.T) { testBuildPayload(t, false, false) })
+	t.Run("with-tx-pool-interrupt", func(t *testing.T) { testBuildPayload(t, false, true) })
 }
 
-func testBuildPayload(t *testing.T, noTxPool bool) {
+func testBuildPayload(t *testing.T, noTxPool, interrupt bool) {
 	var (
 		db        = rawdb.NewMemoryDatabase()
 		recipient = common.HexToAddress("0xdeadbeef")
 	)
 	w, b := newTestWorker(t, params.TestChainConfig, ethash.NewFaker(), db, 0)
 	defer w.close()
 
+	const numInterruptTxs = 256
+	if interrupt {
+		// when donig interrupt testing, create a large pool so interruption will
+		// definitely be visible.
+		txs := genTxs(1, numInterruptTxs)
+		b.txPool.Add(txs, true, false)
+	}
+
 	timestamp := uint64(time.Now().Unix())
 	args := &BuildPayloadArgs{
 		Parent:       b.chain.CurrentBlock().Hash(),
@@ -74,8 +86,10 @@ func testBuildPayload(t *testing.T, noTxPool bool) {
 		if payload.FeeRecipient != recipient {
 			t.Fatal("Unexpect fee recipient")
 		}
-		if len(payload.Transactions) != txs {
+		if !interrupt && len(payload.Transactions) != txs {
 			t.Fatalf("Unexpect transaction set: got %d, expected %d", len(payload.Transactions), txs)
+		} else if interrupt && len(payload.Transactions) >= txs {
+			t.Fatalf("Unexpect transaction set: got %d, expected less than %d", len(payload.Transactions), txs)
 		}
 	}
 
@@ -85,7 +99,13 @@ func testBuildPayload(t *testing.T, noTxPool bool) {
 		verify(empty, 0)
 		full := payload.ResolveFull()
 		verify(full, 0)
-	} else {
+	} else if interrupt {
+		full := payload.ResolveFull()
+		verify(full, len(pendingTxs)+numInterruptTxs)
+	} else { // tx-pool and no interrupt
+		// wait to fully build the first block
+		// if we call ResolveFull too fast, it interrupts it and doesn't add any tx
+		time.Sleep(time.Second)
 		full := payload.ResolveFull()
 		verify(full, len(pendingTxs))
 	}
@@ -99,6 +119,22 @@ func testBuildPayload(t *testing.T, noTxPool bool) {
 	}
 }
 
+func genTxs(startNonce, count uint64) types.Transactions {
+	txs := make(types.Transactions, 0, count)
+	signer := types.LatestSigner(params.TestChainConfig)
+	for nonce := startNonce; nonce < startNonce+count; nonce++ {
+		txs = append(txs, types.MustSignNewTx(testBankKey, signer, &types.AccessListTx{
+			ChainID:  params.TestChainConfig.ChainID,
+			Nonce:    nonce,
+			To:       &testUserAddress,
+			Value:    big.NewInt(1000),
+			Gas:      params.TxGas,
+			GasPrice: big.NewInt(params.InitialBaseFee),
+		}))
+	}
+	return txs
+}
+
 func TestPayloadId(t *testing.T) {
 	ids := make(map[string]int)
 	for i, tt := range []*BuildPayloadArgs{