blockchainer: drop the package completely

It's not an ideal solution, but at least it solves the problem for
now. Caveats:
 * consensus only needs one method, so it's mirrored to Blockchain
 * rpcsrv uses core.* definition of the StateRoot (so technically it might as
   well not have an internal Ledger), but it uses core already unfortunately

internal/fakechain/fakechain.go

@@ -9,7 +9,6 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/config"
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
-	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
 	"github.com/nspcc-dev/neo-go/pkg/core/mempool"
 	"github.com/nspcc-dev/neo-go/pkg/core/mpt"
@@ -293,11 +292,6 @@ func (chain *FakeChain) GetEnrollments() ([]state.Validator, error) {
 	panic("TODO")
 }
 
-// GetStateModule implements the Blockchainer interface.
-func (chain *FakeChain) GetStateModule() blockchainer.StateRoot {
-	return nil
-}
-
 // GetStorageItem implements the Blockchainer interface.
 func (chain *FakeChain) GetStorageItem(id int32, key []byte) state.StorageItem {
 	panic("TODO")

pkg/consensus/consensus.go

@@ -13,9 +13,9 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/config"
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
 	coreb "github.com/nspcc-dev/neo-go/pkg/core/block"
-	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
 	"github.com/nspcc-dev/neo-go/pkg/core/mempool"
+	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
@@ -50,7 +50,7 @@ type Ledger interface {
 	GetConfig() config.ProtocolConfiguration
 	GetMemPool() *mempool.Pool
 	GetNextBlockValidators() ([]*keys.PublicKey, error)
-	GetStateModule() blockchainer.StateRoot
+	GetStateRoot(height uint32) (*state.MPTRoot, error)
 	GetTransaction(util.Uint256) (*transaction.Transaction, uint32, error)
 	GetValidators() ([]*keys.PublicKey, error)
 	PoolTx(t *transaction.Transaction, pools ...*mempool.Pool) error
@@ -250,7 +250,7 @@ func (s *service) newPrepareRequest() payload.PrepareRequest {
 	r := new(prepareRequest)
 	if s.ProtocolConfiguration.StateRootInHeader {
 		r.stateRootEnabled = true
-		if sr, err := s.Chain.GetStateModule().GetStateRoot(s.dbft.BlockIndex - 1); err == nil {
+		if sr, err := s.Chain.GetStateRoot(s.dbft.BlockIndex - 1); err == nil {
 			r.stateRoot = sr.Root
 		} else {
 			panic(err)
@@ -535,7 +535,7 @@ func (s *service) verifyRequest(p payload.ConsensusPayload) error {
 		return errInvalidVersion
 	}
 	if s.ProtocolConfiguration.StateRootInHeader {
-		sr, err := s.Chain.GetStateModule().GetStateRoot(s.dbft.BlockIndex - 1)
+		sr, err := s.Chain.GetStateRoot(s.dbft.BlockIndex - 1)
 		if err != nil {
 			return err
 		} else if sr.Root != req.stateRoot {
@@ -689,7 +689,7 @@ func (s *service) newBlockFromContext(ctx *dbft.Context) block.Block {
 	block.Block.Nonce = ctx.Nonce
 	block.Block.Index = ctx.BlockIndex
 	if s.ProtocolConfiguration.StateRootInHeader {
-		sr, err := s.Chain.GetStateModule().GetStateRoot(ctx.BlockIndex - 1)
+		sr, err := s.Chain.GetStateRoot(ctx.BlockIndex - 1)
 		if err != nil {
 			s.log.Fatal(fmt.Sprintf("failed to get state root: %s", err.Error()))
 		}

pkg/consensus/consensus_test.go

@@ -321,7 +321,7 @@ func TestService_PrepareRequest(t *testing.T) {
 		prevHash:         prevHash,
 	})
 
-	sr, err := srv.Chain.GetStateModule().GetStateRoot(srv.dbft.BlockIndex - 1)
+	sr, err := srv.Chain.GetStateRoot(srv.dbft.BlockIndex - 1)
 	require.NoError(t, err)
 
 	checkRequest(t, errInvalidTransactionsCount, &prepareRequest{stateRootEnabled: true,

pkg/core/blockchain.go

@@ -15,7 +15,6 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/config"
 	"github.com/nspcc-dev/neo-go/pkg/config/limits"
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
-	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer"
 	"github.com/nspcc-dev/neo-go/pkg/core/dao"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/contract"
@@ -181,6 +180,18 @@ type Blockchain struct {
 	unsubCh chan interface{}
 }
 
+// StateRoot represents local state root module.
+type StateRoot interface {
+	CurrentLocalHeight() uint32
+	CurrentLocalStateRoot() util.Uint256
+	CurrentValidatedHeight() uint32
+	FindStates(root util.Uint256, prefix, start []byte, max int) ([]storage.KeyValue, error)
+	GetState(root util.Uint256, key []byte) ([]byte, error)
+	GetStateProof(root util.Uint256, key []byte) ([][]byte, error)
+	GetStateRoot(height uint32) (*state.MPTRoot, error)
+	GetLatestStateHeight(root util.Uint256) (uint32, error)
+}
+
 // bcEvent is an internal event generated by the Blockchain and then
 // broadcasted to other parties. It joins the new block and associated
 // invocation logs, all the other events visible from outside can be produced
@@ -995,8 +1006,13 @@ func (bc *Blockchain) addHeaders(verify bool, headers ...*block.Header) error {
 	return nil
 }
 
+// GetStateRoot returns state root for the given height.
+func (bc *Blockchain) GetStateRoot(height uint32) (*state.MPTRoot, error) {
+	return bc.stateRoot.GetStateRoot(height)
+}
+
 // GetStateModule returns state root service instance.
-func (bc *Blockchain) GetStateModule() blockchainer.StateRoot {
+func (bc *Blockchain) GetStateModule() StateRoot {
 	return bc.stateRoot
 }
 

pkg/core/blockchainer/state_root.go

@@ -1,19 +0,0 @@
-package blockchainer
-
-import (
-	"github.com/nspcc-dev/neo-go/pkg/core/state"
-	"github.com/nspcc-dev/neo-go/pkg/core/storage"
-	"github.com/nspcc-dev/neo-go/pkg/util"
-)
-
-// StateRoot represents local state root module.
-type StateRoot interface {
-	CurrentLocalHeight() uint32
-	CurrentLocalStateRoot() util.Uint256
-	CurrentValidatedHeight() uint32
-	FindStates(root util.Uint256, prefix, start []byte, max int) ([]storage.KeyValue, error)
-	GetState(root util.Uint256, key []byte) ([]byte, error)
-	GetStateProof(root util.Uint256, key []byte) ([][]byte, error)
-	GetStateRoot(height uint32) (*state.MPTRoot, error)
-	GetLatestStateHeight(root util.Uint256) (uint32, error)
-}

pkg/services/rpcsrv/server.go

@@ -25,7 +25,6 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
 	"github.com/nspcc-dev/neo-go/pkg/core"
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
-	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer"
 	"github.com/nspcc-dev/neo-go/pkg/core/fee"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/iterator"
@@ -87,7 +86,7 @@ type (
 		GetNextBlockValidators() ([]*keys.PublicKey, error)
 		GetNotaryContractScriptHash() util.Uint160
 		GetNotaryServiceFeePerKey() int64
-		GetStateModule() blockchainer.StateRoot
+		GetStateModule() core.StateRoot
 		GetStorageItem(id int32, key []byte) state.StorageItem
 		GetTestHistoricVM(t trigger.Type, tx *transaction.Transaction, b *block.Block) (*interop.Context, error)
 		GetTestVM(t trigger.Type, tx *transaction.Transaction, b *block.Block) *interop.Context