Merge pull request #990 from silasdavis/hotfix-checkpoint

Reinstate initial version save to maintain compatibility!

core/kernel.go

@@ -109,7 +109,7 @@ func NewKernel(ctx context.Context, keyClient keys.KeyClient, privValidator tmTy
 	// These should be in sync unless we are at the genesis block
 	if kern.Blockchain.LastBlockHeight() > 0 {
 		kern.Logger.InfoMsg("Loading application state")
-		kern.State, err = execution.LoadState(stateDB, int64(kern.Blockchain.LastBlockHeight()))
+		kern.State, err = execution.LoadState(stateDB, int64(kern.Blockchain.LastBlockHeight()+execution.VersionOffset))
 		if err != nil {
 			return nil, fmt.Errorf("could not load persisted execution state at hash 0x%X: %v",
 				kern.Blockchain.AppHashAfterLastBlock(), err)

execution/execution.go

@@ -343,8 +343,9 @@ func (exe *executor) Commit(blockHash []byte, blockTime time.Time, header *abciT
 		"total_validator_power", exe.blockchain.CurrentValidators().TotalPower(),
 		"total_validator_power_change", totalPowerChange,
 		"total_validator_flow", totalFlow)
-	if uint64(version) != exe.blockchain.LastBlockHeight() {
-		return nil, fmt.Errorf("state tree version %d does not equal blockchain height %d but their equality "+
+	// TODO: revert this to straight equality by removing the initial write on MakeGenesisState
+	if uint64(version) != exe.blockchain.LastBlockHeight()+VersionOffset {
+		return nil, fmt.Errorf("state tree version %d does not equal blockchain height %d + 1 but that "+
 			"is meant to be a guaranteed invariant", version, exe.blockchain.LastBlockHeight())
 	}
 

execution/execution_test.go

@@ -1560,7 +1560,7 @@ type testExecutor struct {
 
 func makeExecutor(state *State) *testExecutor {
 	blockchain := newBlockchain(testGenesisDoc)
-	blockchain.CommitBlockAtHeight(time.Now(), []byte("hashily"), state.Hash(), uint64(state.Version()))
+	blockchain.CommitBlockAtHeight(time.Now(), []byte("hashily"), state.Hash(), uint64(state.Version())-VersionOffset)
 	return &testExecutor{
 		executor: newExecutor("makeExecutorCache", true, state, blockchain, event.NewNoOpPublisher(),
 			logger),

execution/state.go

@@ -38,8 +38,9 @@ import (
 )
 
 const (
-	defaultCacheCapacity = 1024
-	uint64Length         = 8
+	VersionOffset        uint64 = 1
+	defaultCacheCapacity        = 1024
+	uint64Length                = 8
 
 	// Prefix under which the versioned merkle state tree resides - tracking previous versions of history
 	treePrefix = "m"
@@ -164,6 +165,12 @@ func MakeGenesisState(db dbm.DB, genesisDoc *genesis.GenesisDoc) (*State, error)
 		return nil, err
 	}
 
+	// TODO: remove this in order to synchronise version and height
+	// We need to save at least once so that readTree points at a non-working-state tree
+	_, _, err = s.writeState.commit()
+	if err != nil {
+		return nil, err
+	}
 	return s, nil
 }