fix(miner): payload building writing to closed channel (ethereum#91)

miner/payload_building.go

@@ -69,6 +69,7 @@ type Payload struct {
 	stop     chan struct{}
 	lock     sync.Mutex
 	cond     *sync.Cond
+	done     chan struct{} // CHANGE(taiko): done channel to communicate we shouldnt write to stop chan
 }
 
 // newPayload initializes the payload object.
@@ -77,6 +78,7 @@ func newPayload(empty *types.Block, id engine.PayloadID) *Payload {
 		id:    id,
 		empty: empty,
 		stop:  make(chan struct{}),
+		done:  make(chan struct{}, 1), // CHANGE(taiko): buffered channel to communicate done to taiko payload builder
 	}
 	log.Info("Starting work on payload", "id", payload.id)
 	payload.cond = sync.NewCond(&payload.lock)
@@ -117,6 +119,7 @@ func (payload *Payload) Resolve() *engine.ExecutionPayloadEnvelope {
 	select {
 	case <-payload.stop:
 	default:
+		payload.done <- struct{}{} // CHANGE(taiko): signal to taiko payload builder to not write to payload.stop channel
 		close(payload.stop)
 	}
 	if payload.full != nil {

miner/taiko_payload_building.go

@@ -18,6 +18,8 @@ func (payload *Payload) SetFullBlock(block *types.Block, fees *big.Int) {
 		defer payload.lock.Unlock()
 
 		select {
+		case <-payload.done:
+			log.Info("SetFullBlock payload done received", "id", payload.id)
 		case payload.stop <- struct{}{}:
 		default:
 		}

miner/taiko_payload_building_test.go

@@ -0,0 +1,83 @@
+package miner
+
+import (
+	"math/big"
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/consensus/ethash"
+	"github.com/ethereum/go-ethereum/core/rawdb"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/params"
+	"github.com/ethereum/go-ethereum/trie"
+	"github.com/stretchr/testify/assert"
+)
+
+func newTestBlock() *types.Block {
+	tx1 := types.NewTransaction(1, common.BytesToAddress([]byte{0x11}), big.NewInt(111), 1111, big.NewInt(11111), []byte{0x11, 0x11, 0x11})
+	txs := []*types.Transaction{tx1}
+
+	block := types.NewBlock(&types.Header{Number: big.NewInt(314)}, txs, nil, nil, trie.NewStackTrie(nil))
+	return block
+}
+
+func Test_SetFullBlock_AvoidPanic(t *testing.T) {
+	var (
+		db        = rawdb.NewMemoryDatabase()
+		recipient = common.HexToAddress("0xdeadbeef")
+	)
+	w, b := newTestWorker(t, params.TestChainConfig, ethash.NewFaker(), db, 0)
+	defer w.close()
+
+	timestamp := uint64(time.Now().Unix())
+	args := &BuildPayloadArgs{
+		Parent:       b.chain.CurrentBlock().Hash(),
+		Timestamp:    timestamp,
+		Random:       common.Hash{},
+		FeeRecipient: recipient,
+	}
+	payload, err := w.buildPayload(args)
+	if err != nil {
+		t.Fatalf("Failed to build payload %v", err)
+	}
+
+	fees := big.NewInt(1)
+
+	payload.done <- struct{}{}
+	close(payload.stop)
+
+	block := newTestBlock()
+	// expect not to panic sending to payload.stop
+	// now that done is closed
+	payload.SetFullBlock(block, fees)
+}
+
+func Test_SetFullBlock(t *testing.T) {
+	var (
+		db        = rawdb.NewMemoryDatabase()
+		recipient = common.HexToAddress("0xdeadbeef")
+	)
+	w, b := newTestWorker(t, params.TestChainConfig, ethash.NewFaker(), db, 0)
+	defer w.close()
+
+	timestamp := uint64(time.Now().Unix())
+	args := &BuildPayloadArgs{
+		Parent:       b.chain.CurrentBlock().Hash(),
+		Timestamp:    timestamp,
+		Random:       common.Hash{},
+		FeeRecipient: recipient,
+	}
+	payload, err := w.buildPayload(args)
+	if err != nil {
+		t.Fatalf("Failed to build payload %v", err)
+	}
+
+	fees := big.NewInt(1)
+
+	block := newTestBlock()
+	payload.SetFullBlock(block, fees)
+
+	assert.Equal(t, block, payload.full)
+	assert.Equal(t, fees, payload.fullFees)
+}