core: fix contract manifest unpacking in System.Contract.Create

It's just JSON, io.Serializable is only used for DB storage where the length
should be obtained from the stream. Fixes:

2020-06-18T22:14:10.571+0300    WARN    contract invocation failed      {"tx": "1ffd475a9c246495d6206cb80a9a78e9d14a433ded60cd37aa87d897655606e1", "block": 25893, "error": "error encountered at instruction 3696 (SYSCALL): failed to invoke syscall: invalid character ':' after top-level value"}

pkg/core/helper_test.go

@@ -234,7 +234,7 @@ func TestCreateBasicChain(t *testing.T) {
 	}
 	m.ABI.EntryPoint.ReturnType = smartcontract.BoolType
 	m.Features = smartcontract.HasStorage
-	bs, err := testserdes.EncodeBinary(m)
+	bs, err := m.MarshalJSON()
 	require.NoError(t, err)
 	emit.Bytes(script.BinWriter, bs)
 	emit.Bytes(script.BinWriter, avm)

pkg/core/interop_neo.go

@@ -8,7 +8,6 @@ import (
 
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
-	"github.com/nspcc-dev/neo-go/pkg/io"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/nspcc-dev/neo-go/pkg/vm"
@@ -76,10 +75,9 @@ func createContractStateFromVM(ic *interop.Context, v *vm.VM) (*state.Contract,
 		return nil, errGasLimitExceeded
 	}
 	var m manifest.Manifest
-	r := io.NewBinReaderFromBuf(manifestBytes)
-	m.DecodeBinary(r)
-	if r.Err != nil {
-		return nil, r.Err
+	err := m.UnmarshalJSON(manifestBytes)
+	if err != nil {
+		return nil, err
 	}
 	return &state.Contract{
 		Script:   script,

pkg/rpc/request/txBuilder.go

@@ -19,9 +19,10 @@ import (
 // with its metadata and system fee require for this.
 func CreateDeploymentScript(avm []byte, manif *manifest.Manifest) ([]byte, util.Fixed8, error) {
 	script := io.NewBufBinWriter()
-	w := io.NewBufBinWriter()
-	manif.EncodeBinary(w.BinWriter)
-	rawManifest := w.Bytes()
+	rawManifest, err := manif.MarshalJSON()
+	if err != nil {
+		return nil, 0, err
+	}
 	emit.Bytes(script.BinWriter, rawManifest)
 	emit.Bytes(script.BinWriter, avm)
 	emit.Syscall(script.BinWriter, "System.Contract.Create")

pkg/rpc/server/server_test.go

@@ -51,7 +51,7 @@ type rpcTestCase struct {
 }
 
 const testContractHash = "e65ff7b3a02d207b584a5c27057d4e9862ef01da"
-const deploymentTxHash = "5ce44eae362d3f81d440cb73cf4e4af71e69851bcd683b076aa08b7346d4e69b"
+const deploymentTxHash = "b0428600383ec7f7b06734978a24dbe81edc87b781f58c0614f122c735d8cf6a"
 
 var rpcTestCases = map[string][]rpcTestCase{
 	"getapplicationlog": {
@@ -148,7 +148,7 @@ var rpcTestCases = map[string][]rpcTestCase{
 						},
 						{
 							Asset:       e.chain.UtilityTokenHash(),
-							Amount:      "923.96934740",
+							Amount:      "923.96937740",
 							LastUpdated: 6,
 						}},
 					Address: testchain.PrivateKeyByID(0).GetScriptHash().StringLE(),