fix pending block null issue (#358)

miner/miner.go

@@ -184,19 +184,21 @@ func (miner *Miner) SetRecommitInterval(interval time.Duration) {
 // Pending returns the currently pending block and associated state.
 func (miner *Miner) Pending() (*types.Block, *state.StateDB) {
  if miner.worker.isRunning() {
- return miner.worker.pending()
- } else {
- // fallback to latest block
- block := miner.worker.chain.CurrentBlock()
- if block == nil {
- return nil, nil
+ pendingBlock, pendingState := miner.worker.pending()
+ if pendingState != nil && pendingBlock != nil {
+ return pendingBlock, pendingState
  }
- stateDb, err := miner.worker.chain.StateAt(block.Root())
- if err != nil {
- return nil, nil
- }
- return block, stateDb
  }
+ // fallback to latest block
+ block := miner.worker.chain.CurrentBlock()
+ if block == nil {
+ return nil, nil
+ }
+ stateDb, err := miner.worker.chain.StateAt(block.Root())
+ if err != nil {
+ return nil, nil
+ }
+ return block, stateDb
 }
 
 // PendingBlock returns the currently pending block.
@@ -206,11 +208,13 @@ func (miner *Miner) Pending() (*types.Block, *state.StateDB) {
 // change between multiple method calls
 func (miner *Miner) PendingBlock() *types.Block {
  if miner.worker.isRunning() {
- return miner.worker.pendingBlock()
- } else {
- // fallback to latest block
- return miner.worker.chain.CurrentBlock()
+ pendingBlock := miner.worker.pendingBlock()
+  if pendingBlock != nil {
+  return pendingBlock
+ }
  }
+ // fallback to latest block
+ return miner.worker.chain.CurrentBlock()
 }
 
 func (miner *Miner) SetEtherbase(addr common.Address) {