eth: explicitly commented the code were bor could get into snap-sync …

…mode (#1243)

* eth: explicitly commented the code were bor could get into snap-sync mode

* addressed comment

eth/handler.go

@@ -178,7 +178,9 @@ func newHandler(config *handlerConfig) (*handler, error) {
 			h.snapSync.Store(true)
 			log.Warn("Switch sync mode from full sync to snap sync", "reason", "snap sync incomplete")
 		} else if !h.chain.HasState(fullBlock.Root) {
-			h.snapSync.Store(true)
+			// TODO - uncomment when we (Polygon-PoS, bor) have snap sync/pbss
+			// For more info - https://github.com/ethereum/go-ethereum/pull/28171
+			// h.snapSync.Store(true)
 			log.Warn("Switch sync mode from full sync to snap sync", "reason", "head state missing")
 		}
 	} else {

eth/sync.go

@@ -200,59 +200,47 @@ func peerToSyncOp(mode downloader.SyncMode, p *eth.Peer) *chainSyncOp {
 }
 
 func (cs *chainSyncer) modeAndLocalHead() (downloader.SyncMode, *big.Int) {
-	// If we're in snap sync mode, return that directly
-	if cs.handler.snapSync.Load() {
-		block := cs.handler.chain.CurrentSnapBlock()
-		td := cs.handler.chain.GetTd(block.Hash(), block.Number.Uint64())
-		return downloader.SnapSync, td
-	}
+	// TODO - uncomment when we (Polygon-PoS, bor) have snap sync/pbss
+	/*
+		// If we're in snap sync mode, return that directly
+		if cs.handler.snapSync.Load() {
+			block := cs.handler.chain.CurrentSnapBlock()
+			td := cs.handler.chain.GetTd(block.Hash(), block.Number.Uint64())
+			return downloader.SnapSync, td
+		}
+	*/
+
 	// We are probably in full sync, but we might have rewound to before the
 	// snap sync pivot, check if we should re-enable snap sync.
 	head := cs.handler.chain.CurrentBlock()
-	if pivot := rawdb.ReadLastPivotNumber(cs.handler.database); pivot != nil {
-		if head.Number.Uint64() < *pivot {
+	// TODO - uncomment when we (Polygon-PoS, bor) have snap sync/pbss
+	/*
+		if pivot := rawdb.ReadLastPivotNumber(cs.handler.database); pivot != nil {
+			if head.Number.Uint64() < *pivot {
+				block := cs.handler.chain.CurrentSnapBlock()
+				td := cs.handler.chain.GetTd(block.Hash(), block.Number.Uint64())
+				return downloader.SnapSync, td
+			}
+		}
+	*/
+
+	// TODO - uncomment when we (Polygon-PoS, bor) have snap sync/pbss
+	// For more info - https://github.com/ethereum/go-ethereum/pull/28171
+	/*
+		// We are in a full sync, but the associated head state is missing. To complete
+		// the head state, forcefully rerun the snap sync. Note it doesn't mean the
+		// persistent state is corrupted, just mismatch with the head block.
+		if !cs.handler.chain.HasState(head.Root) {
 			block := cs.handler.chain.CurrentSnapBlock()
 			td := cs.handler.chain.GetTd(block.Hash(), block.Number.Uint64())
+			log.Info("Reenabled snap sync as chain is stateless")
 			return downloader.SnapSync, td
 		}
-	}
-	// We are in a full sync, but the associated head state is missing. To complete
-	// the head state, forcefully rerun the snap sync. Note it doesn't mean the
-	// persistent state is corrupted, just mismatch with the head block.
-	if !cs.handler.chain.HasState(head.Root) {
-		block := cs.handler.chain.CurrentSnapBlock()
-		td := cs.handler.chain.GetTd(block.Hash(), block.Number.Uint64())
-		log.Info("Reenabled snap sync as chain is stateless")
-		return downloader.SnapSync, td
-	}
+	*/
 	// Nope, we're really full syncing
 	td := cs.handler.chain.GetTd(head.Hash(), head.Number.Uint64())
 
 	return downloader.FullSync, td
-	// TODO(snap): Uncomment when we have snap sync working
-	// If we're in snap sync mode, return that directly
-	//
-	//	if atomic.LoadUint32(&cs.handler.snapSync) == 1 {
-	//		block := cs.handler.chain.CurrentFastBlock()
-	//		td := cs.handler.chain.GetTd(block.Hash(), block.NumberU64())
-	//		return downloader.SnapSync, td
-	//	}
-	//
-	// // We are probably in full sync, but we might have rewound to before the
-	// // snap sync pivot, check if we should reenable
-	//
-	//	if pivot := rawdb.ReadLastPivotNumber(cs.handler.database); pivot != nil {
-	//		if head := cs.handler.chain.CurrentBlock(); head.NumberU64() < *pivot {
-	//			block := cs.handler.chain.CurrentFastBlock()
-	//			td := cs.handler.chain.GetTd(block.Hash(), block.NumberU64())
-	//			return downloader.SnapSync, td
-	//		}
-	//	}
-	//
-	// // Nope, we're really full syncing
-	// head := cs.handler.chain.CurrentBlock()
-	// td := cs.handler.chain.GetTd(head.Hash(), head.NumberU64())
-	// return downloader.FullSync, td
 }
 
 // startSync launches doSync in a new goroutine.