config: consolidate ProtocolConfiguration consistency checks

pkg/config/config.go

@@ -6,7 +6,6 @@ import (
 	"os"
 
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
-	"github.com/nspcc-dev/neo-go/pkg/core/native/nativenames"
 	"github.com/nspcc-dev/neo-go/pkg/rpc"
 	"gopkg.in/yaml.v2"
 )
@@ -63,10 +62,9 @@ func LoadFile(configPath string) (Config, error) {
 		return Config{}, fmt.Errorf("failed to unmarshal config YAML: %w", err)
 	}
 
-	for name := range config.ProtocolConfiguration.NativeUpdateHistories {
-		if !nativenames.IsValid(name) {
-			return Config{}, fmt.Errorf("NativeActivations configuration section contains unexpected native contract name: %s", name)
-		}
+	err = config.ProtocolConfiguration.Validate()
+	if err != nil {
+		return Config{}, err
 	}
 
 	return config, nil

pkg/config/protocol_config.go

@@ -1,7 +1,11 @@
 package config
 
 import (
+	"errors"
+	"fmt"
+
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
+	"github.com/nspcc-dev/neo-go/pkg/core/native/nativenames"
 	"github.com/nspcc-dev/neo-go/pkg/encoding/fixedn"
 )
 
@@ -59,3 +63,18 @@ type (
 		VerifyTransactions bool `yaml:"VerifyTransactions"`
 	}
 )
+
+// Validate checks ProtocolConfiguration for internal consistency and returns
+// error if anything inappropriate found. Other methods can rely on protocol
+// validity after this.
+func (p *ProtocolConfiguration) Validate() error {
+	if len(p.StandbyCommittee) < p.ValidatorsCount {
+		return errors.New("validators count can't exceed the size of StandbyCommittee")
+	}
+	for name := range p.NativeUpdateHistories {
+		if !nativenames.IsValid(name) {
+			return fmt.Errorf("NativeActivations configuration section contains unexpected native contract name: %s", name)
+		}
+	}
+	return nil
+}

pkg/config/protocol_config_test.go

@@ -0,0 +1,20 @@
+package config
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestProtocolConfigurationValidation(t *testing.T) {
+	p := &ProtocolConfiguration{
+		ValidatorsCount: 1,
+	}
+	require.Error(t, p.Validate())
+	p = &ProtocolConfiguration{
+		NativeUpdateHistories: map[string][]uint32{
+			"someContract": []uint32{0, 10},
+		},
+	}
+	require.Error(t, p.Validate())
+}

pkg/core/util.go

@@ -1,7 +1,6 @@
 package core
 
 import (
-	"errors"
 	"time"
 
 	"github.com/nspcc-dev/neo-go/pkg/config"
@@ -58,9 +57,6 @@ func validatorsFromConfig(cfg config.ProtocolConfiguration) ([]*keys.PublicKey,
 }
 
 func committeeFromConfig(cfg config.ProtocolConfiguration) ([]*keys.PublicKey, error) {
-	if len(cfg.StandbyCommittee) < cfg.ValidatorsCount {
-		return nil, errors.New("validators count can be less than the size of StandbyCommittee")
-	}
 	validators := make([]*keys.PublicKey, len(cfg.StandbyCommittee))
 	for i := range validators {
 		pubKey, err := keys.NewPublicKeyFromString(cfg.StandbyCommittee[i])