shuffle pending accounts in the transaction pool

common/random/shuffle.go

@@ -0,0 +1,28 @@
+package random
+
+import (
+	"math/rand"
+)
+
+func Shuffle[T any](slice []T) {
+	//nolint:gosec
+	r := rand.New(CryptoSource{}) //CryptoSource is a cryptographic source of randomness
+
+	r.Shuffle(len(slice), func(i, j int) {
+		slice[i], slice[j] = slice[j], slice[i]
+	})
+}
+
+// ShuffleMap returns a shuffled slice of keys to iterate by
+func ShuffleMap[K comparable, V any](m map[K]V) []K {
+	keys := make([]K, len(m))
+
+	i := 0
+
+	for key := range m {
+		keys[i] = key
+		i++
+	}
+
+	return keys
+}

common/random/source.go

@@ -0,0 +1,20 @@
+package random
+
+import (
+	"crypto/rand"
+	"encoding/binary"
+)
+
+type CryptoSource struct{}
+
+func (CryptoSource) Seed(_ int64) {}
+
+func (s CryptoSource) Int63() int64 {
+	return int64(s.Uint64() & ^uint64(1<<63))
+}
+
+func (CryptoSource) Uint64() (v uint64) {
+	_ = binary.Read(rand.Reader, binary.BigEndian, &v)
+
+	return v
+}

core/tx_pool.go

@@ -27,6 +27,7 @@ import (
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/prque"
+	"github.com/ethereum/go-ethereum/common/random"
 	"github.com/ethereum/go-ethereum/consensus/misc"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
@@ -538,7 +539,11 @@ func (pool *TxPool) Pending(enforceTips bool) map[common.Address]types.Transacti
 	defer pool.mu.Unlock()
 
 	pending := make(map[common.Address]types.Transactions)
-	for addr, list := range pool.pending {
+	addresses := random.ShuffleMap(pool.pending)
+
+	for _, addr := range addresses {
+		list := pool.pending[addr]
+
 		txs := list.Flatten()
 
 		// If the miner requests tip enforcement, cap the lists now
@@ -554,6 +559,7 @@ func (pool *TxPool) Pending(enforceTips bool) map[common.Address]types.Transacti
 			pending[addr] = txs
 		}
 	}
+
 	return pending
 }