eth: remove usage of tdd

eth/ethconfig/config.go

@@ -18,7 +18,6 @@
 package ethconfig
 
 import (
-	"errors"
 	"math/big"
 	"time"
 
@@ -238,11 +237,5 @@ func CreateConsensusEngine(chainConfig *params.ChainConfig, ethConfig *Config, d
 			return bor.New(chainConfig, db, blockchainAPI, spanner, heimdallClient, genesisContractsClient, false), nil
 		}
 	}
-	// If defaulting to proof-of-work, enforce an already merged network since
-	// we cannot run PoW algorithms anymore, so we cannot even follow a chain
-	// not coordinated by a beacon node.
-	if !chainConfig.TerminalTotalDifficultyPassed {
-		return nil, errors.New("ethash is only supported as a historical component of already merged networks")
-	}
 	return beacon.New(ethash.NewFaker()), nil
 }

eth/fetcher/block_fetcher.go

@@ -576,7 +576,7 @@ func (f *BlockFetcher) loop() {
 					case res := <-resCh:
 						res.Done <- nil
 						// Ignoring withdrawals here, since the block fetcher is not used post-merge.
-						txs, uncles, _, _ := res.Res.(*eth.BlockBodiesResponse).Unpack()
+						txs, uncles, _ := res.Res.(*eth.BlockBodiesResponse).Unpack()
 						f.FilterBodies(peer, txs, uncles, time.Now(), announcedAt)
 
 					case <-timeout.C:

eth/handler.go

@@ -203,20 +203,7 @@ func newHandler(config *handlerConfig) (*handler, error) {
 	}
 	// Construct the downloader (long sync)
 	h.downloader = downloader.New(config.Database, h.eventMux, h.chain, nil, h.removePeer, h.enableSyncedFeatures, config.checker)
-	if ttd := h.chain.Config().TerminalTotalDifficulty; ttd != nil {
-		if h.chain.Config().TerminalTotalDifficultyPassed {
-			log.Info("Chain post-merge, sync via beacon client")
-		} else {
-			head := h.chain.CurrentBlock()
-			if td := h.chain.GetTd(head.Hash(), head.Number.Uint64()); td.Cmp(ttd) >= 0 {
-				log.Info("Chain post-TTD, sync via beacon client")
-			} else {
-				log.Warn("Chain pre-merge, sync via PoW (ensure beacon client is ready)")
-			}
-		}
-	} else if h.chain.Config().TerminalTotalDifficultyPassed {
-		log.Error("Chain configured post-merge, but without TTD. Are you debugging sync?")
-	}
+
 	// Construct the fetcher (short sync)
 	validator := func(header *types.Header) error {
 		// Reject all the PoS style headers in the first place. No matter

eth/protocols/eth/handler_test.go

@@ -96,7 +96,6 @@ func newTestBackendWithGenerator(blocks int, shanghai bool, generator func(int,
 			MergeNetsplitBlock:      big.NewInt(0),
 			ShanghaiBlock:           big.NewInt(0),
 			TerminalTotalDifficulty: big.NewInt(0),
-			TerminalTotalDifficultyPassed: true,
 			Ethash:                  new(params.EthashConfig),
 			Bor:                     params.TestChainConfig.Bor,
 		}

eth/sync.go

@@ -146,17 +146,6 @@ func (cs *chainSyncer) nextSyncOp() *chainSyncOp {
 	if cs.doneCh != nil {
 		return nil // Sync already running
 	}
-	// If a beacon client once took over control, disable the entire legacy sync
-	// path from here on end. Note, there is a slight "race" between reaching TTD
-	// and the beacon client taking over. The downloader will enforce that nothing
-	// above the first TTD will be delivered to the chain for import.
-	//
-	// An alternative would be to check the local chain for exceeding the TTD and
-	// avoid triggering a sync in that case, but that could also miss sibling or
-	// other family TTD block being accepted.
-	if cs.handler.chain.Config().TerminalTotalDifficultyPassed {
-		return nil
-	}
 	// Ensure we're at minimum peer count.
 	minPeers := defaultMinSyncPeers
 	if cs.forced {