core, eth, internal, les, light: consistent error handling

core/blockchain.go

@@ -195,7 +195,9 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, chainConfig *par
 			// make sure the headerByNumber (if present) is in our current canonical chain
 			if headerByNumber != nil && headerByNumber.Hash() == header.Hash() {
 				log.Error("Found bad hash, rewinding chain", "number", header.Number, "hash", header.ParentHash)
-				bc.SetHead(header.Number.Uint64() - 1)
+				if err := bc.SetHead(header.Number.Uint64() - 1); err != nil {
+					return nil, err
+				}
 				log.Error("Chain rewind was successful, resuming normal operation")
 			}
 		}

eth/api_backend.go

@@ -51,9 +51,9 @@ func (b *EthAPIBackend) CurrentBlock() *types.Block {
 	return b.eth.blockchain.CurrentBlock()
 }
 
-func (b *EthAPIBackend) SetHead(number uint64) {
+func (b *EthAPIBackend) SetHead(number uint64) error {
 	b.eth.protocolManager.downloader.Cancel()
-	b.eth.blockchain.SetHead(number)
+	return b.eth.blockchain.SetHead(number)
 }
 
 func (b *EthAPIBackend) HeaderByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*types.Header, error) {

eth/backend.go

@@ -171,7 +171,9 @@ func New(ctx *node.ServiceContext, config *Config) (*Ethereum, error) {
 	// Rewind the chain in case of an incompatible config upgrade.
 	if compat, ok := genesisErr.(*params.ConfigCompatError); ok {
 		log.Warn("Rewinding chain to upgrade configuration", "err", compat)
-		eth.blockchain.SetHead(compat.RewindTo)
+		if err := eth.blockchain.SetHead(compat.RewindTo); err != nil {
+			return nil, err
+		}
 		rawdb.WriteChainConfig(chainDb, genesisHash, chainConfig)
 	}
 	eth.bloomIndexer.Start(eth.blockchain)
@@ -315,8 +317,8 @@ func (s *Ethereum) APIs() []rpc.API {
 	}...)
 }
 
-func (s *Ethereum) ResetWithGenesisBlock(gb *types.Block) {
+func (s *Ethereum) ResetWithGenesisBlock(gb *types.Block) error {
-	s.blockchain.ResetWithGenesisBlock(gb)
+	return s.blockchain.ResetWithGenesisBlock(gb)
 }
 
 func (s *Ethereum) Etherbase() (eb common.Address, err error) {

internal/ethapi/api.go

@@ -1574,8 +1574,8 @@ func (api *PrivateDebugAPI) ChaindbCompact() error {
 }
 
 // SetHead rewinds the head of the blockchain to a previous block.
-func (api *PrivateDebugAPI) SetHead(number hexutil.Uint64) {
+func (api *PrivateDebugAPI) SetHead(number hexutil.Uint64) error {
-	api.b.SetHead(uint64(number))
+	return api.b.SetHead(uint64(number))
 }
 
 // PublicNetAPI offers network related RPC methods

internal/ethapi/backend.go

@@ -46,7 +46,7 @@ type Backend interface {
 	AccountManager() *accounts.Manager
 
 	// BlockChain API
-	SetHead(number uint64)
+	SetHead(number uint64) error
 	HeaderByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*types.Header, error)
 	BlockByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*types.Block, error)
 	StateAndHeaderByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*state.StateDB, *types.Header, error)

les/api_backend.go

@@ -51,9 +51,9 @@ func (b *LesApiBackend) CurrentBlock() *types.Block {
 	return types.NewBlockWithHeader(b.eth.BlockChain().CurrentHeader())
 }
 
-func (b *LesApiBackend) SetHead(number uint64) {
+func (b *LesApiBackend) SetHead(number uint64) error {
 	b.eth.protocolManager.downloader.Cancel()
-	b.eth.blockchain.SetHead(number)
+	return b.eth.blockchain.SetHead(number)
 }
 
 func (b *LesApiBackend) HeaderByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*types.Header, error) {

les/backend.go

@@ -135,7 +135,9 @@ func New(ctx *node.ServiceContext, config *eth.Config) (*LightEthereum, error) {
 	// Rewind the chain in case of an incompatible config upgrade.
 	if compat, ok := genesisErr.(*params.ConfigCompatError); ok {
 		log.Warn("Rewinding chain to upgrade configuration", "err", compat)
-		leth.blockchain.SetHead(compat.RewindTo)
+		if err := leth.blockchain.SetHead(compat.RewindTo); err != nil {
+			return nil, err
+		}
 		rawdb.WriteChainConfig(chainDb, genesisHash, chainConfig)
 	}
 
@@ -238,8 +240,8 @@ func (s *LightEthereum) APIs() []rpc.API {
 	}...)
 }
 
-func (s *LightEthereum) ResetWithGenesisBlock(gb *types.Block) {
+func (s *LightEthereum) ResetWithGenesisBlock(gb *types.Block) error {
-	s.blockchain.ResetWithGenesisBlock(gb)
+	return s.blockchain.ResetWithGenesisBlock(gb)
 }
 
 func (s *LightEthereum) BlockChain() *light.LightChain      { return s.blockchain }

light/lightchain.go

@@ -109,7 +109,9 @@ func NewLightChain(odr OdrBackend, config *params.ChainConfig, engine consensus.
 	for hash := range core.BadHashes {
 		if header := bc.GetHeaderByHash(hash); header != nil {
 			log.Error("Found bad hash, rewinding chain", "number", header.Number, "hash", header.ParentHash)
-			bc.SetHead(header.Number.Uint64() - 1)
+			if err := bc.SetHead(header.Number.Uint64() - 1); err != nil {
+				return nil, err
+			}
 			log.Error("Chain rewind was successful, resuming normal operation")
 		}
 	}
@@ -146,7 +148,9 @@ func (lc *LightChain) Odr() OdrBackend {
 func (lc *LightChain) loadLastState() error {
 	if head := rawdb.ReadHeadHeaderHash(lc.chainDb); head == (common.Hash{}) {
 		// Corrupt or empty database, init from scratch
-		lc.Reset()
+		if err := lc.Reset(); err != nil {
+			return err
+		}
 	} else {
 		if header := lc.GetHeaderByHash(head); header != nil {
 			lc.hc.SetCurrentHeader(header)
@@ -163,12 +167,12 @@ func (lc *LightChain) loadLastState() error {
 
 // SetHead rewinds the local chain to a new head. Everything above the new
 // head will be deleted and the new one set.
-func (lc *LightChain) SetHead(head uint64) {
+func (lc *LightChain) SetHead(head uint64) error {
 	lc.chainmu.Lock()
 	defer lc.chainmu.Unlock()
 
 	lc.hc.SetHead(head, nil)
-	lc.loadLastState()
+	return lc.loadLastState()
 }
 
 // GasLimit returns the gas limit of the current HEAD block.
@@ -177,16 +181,17 @@ func (lc *LightChain) GasLimit() uint64 {
 }
 
 // Reset purges the entire blockchain, restoring it to its genesis state.
-func (lc *LightChain) Reset() {
+func (lc *LightChain) Reset() error {
-	lc.ResetWithGenesisBlock(lc.genesisBlock)
+	return lc.ResetWithGenesisBlock(lc.genesisBlock)
 }
 
 // ResetWithGenesisBlock purges the entire blockchain, restoring it to the
 // specified genesis state.
-func (lc *LightChain) ResetWithGenesisBlock(genesis *types.Block) {
+func (lc *LightChain) ResetWithGenesisBlock(genesis *types.Block) error {
 	// Dump the entire block chain and purge the caches
-	lc.SetHead(0)
+	if err := lc.SetHead(0); err != nil {
-
+		return err
+	}
 	lc.chainmu.Lock()
 	defer lc.chainmu.Unlock()
 
@@ -197,6 +202,7 @@ func (lc *LightChain) ResetWithGenesisBlock(genesis *types.Block) {
 	lc.genesisBlock = genesis
 	lc.hc.SetGenesis(lc.genesisBlock.Header())
 	lc.hc.SetCurrentHeader(lc.genesisBlock.Header())
+	return nil
 }
 
 // Accessors