miner: use empty zero randomness for pending blocks after the merge

miner/worker.go

@@ -20,7 +20,6 @@ import (
 	"errors"
 	"fmt"
 	"math/big"
-	"math/rand"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -998,17 +997,9 @@ func (w *worker) prepareWork(genParams *generateParams) (*environment, error) {
 	if !genParams.noExtra && len(w.extra) != 0 {
 		header.Extra = w.extra
 	}
-	// Set the randomness field for post-merge blocks, either fed by beacon chain
-	// or generated locally.
+	// Set the randomness field from the beacon chain if it's available.
 	if genParams.random != (common.Hash{}) {
 		header.MixDigest = genParams.random
-	} else if w.isTTDReached(header) {
-		random := make([]byte, common.HashLength)
-		_, err := rand.Read(random)
-		if err != nil {
-			return nil, err
-		}
-		header.MixDigest = common.BytesToHash(random)
 	}
 	// Set baseFee and GasLimit if we are on an EIP-1559 chain
 	if w.chainConfig.IsLondon(header.Number) {

miner/worker_test.go

@@ -580,11 +580,7 @@ func testGetSealingWork(t *testing.T, chainConfig *params.ChainConfig, engine co
 				t.Error("Unexpected coinbase")
 			}
 		}
-		if postMerge && random == (common.Hash{}) {
-			if block.MixDigest() == (common.Hash{}) {
-				t.Error("Unexpected mix digest")
-			}
-		} else if !isClique {
+		if !isClique {
 			if block.MixDigest() != random {
 				t.Error("Unexpected mix digest")
 			}