Merge pull request ethereum#25 from karalabe/merge-interop-spec-sync6

core: overwrite head header and fast block too on block sethead

Author: MariusVanDerWijden

core/blockchain.go

@@ -717,32 +717,24 @@ func (bc *BlockChain) ExportN(w io.Writer, first uint64, last uint64) error {
 //
 // Note, this function assumes that the `mu` mutex is held!
 func (bc *BlockChain) writeHeadBlock(block *types.Block) {
-	// If the block is on a side chain or an unknown one, force other heads onto it too
-	updateHeads := rawdb.ReadCanonicalHash(bc.db, block.NumberU64()) != block.Hash()
-
 	// Add the block to the canonical chain number scheme and mark as the head
 	batch := bc.db.NewBatch()
+	rawdb.WriteHeadHeaderHash(batch, block.Hash())
+	rawdb.WriteHeadFastBlockHash(batch, block.Hash())
 	rawdb.WriteCanonicalHash(batch, block.Hash(), block.NumberU64())
 	rawdb.WriteTxLookupEntriesByBlock(batch, block)
 	rawdb.WriteHeadBlockHash(batch, block.Hash())
 
-	// If the block is better than our head or is on a different chain, force update heads
-	// TODO(rjl493456442) What if the (header head/fast block head) is lower than the chain
-	// head? Is it possible in practise?
-	if updateHeads {
-		rawdb.WriteHeadHeaderHash(batch, block.Hash())
-		rawdb.WriteHeadFastBlockHash(batch, block.Hash())
-	}
 	// Flush the whole batch into the disk, exit the node if failed
 	if err := batch.Write(); err != nil {
 		log.Crit("Failed to update chain indexes and markers", "err", err)
 	}
 	// Update all in-memory chain markers in the last step
-	if updateHeads {
-		bc.hc.SetCurrentHeader(block.Header())
-		bc.currentFastBlock.Store(block)
-		headFastBlockGauge.Update(int64(block.NumberU64()))
-	}
+	bc.hc.SetCurrentHeader(block.Header())
+
+	bc.currentFastBlock.Store(block)
+	headFastBlockGauge.Update(int64(block.NumberU64()))
+
 	bc.currentBlock.Store(block)
 	headBlockGauge.Update(int64(block.NumberU64()))
 }