[#352] Add explicit max number of alphabet nodes

Signed-off-by: Alejandro Lopez <a.lopez@yadro.com>

cmd/frostfs-adm/internal/modules/morph/initialize.go

@@ -23,6 +23,13 @@ import (
 	"github.com/spf13/viper"
 )
 
+const (
+	// maxAlphabetNodes is the maximum number of candidates allowed, which is currently limited by the size
+	// of the invocation script.
+	// See: https://github.com/nspcc-dev/neo-go/blob/740488f7f35e367eaa99a71c0a609c315fe2b0fc/pkg/core/transaction/witness.go#L10
+	maxAlphabetNodes = 22
+)
+
 type cache struct {
 	nnsCs    *state.Contract
 	groupKey *keys.PublicKey
@@ -45,6 +52,8 @@ type initializeContext struct {
 	ContractPath string
 }
 
+var ErrTooManyAlphabetNodes = fmt.Errorf("too many alphabet nodes (maximum allowed is %d)", maxAlphabetNodes)
+
 func initializeSideChainCmd(cmd *cobra.Command, _ []string) error {
 	initCtx, err := newInitializeContext(cmd, viper.GetViper())
 	if err != nil {
@@ -111,6 +120,10 @@ func newInitializeContext(cmd *cobra.Command, v *viper.Viper) (*initializeContex
 		return nil, err
 	}
 
+	if len(wallets) > maxAlphabetNodes {
+		return nil, ErrTooManyAlphabetNodes
+	}
+
 	needContracts := cmd.Name() == "update-contracts" || cmd.Name() == "init"
 
 	var w *wallet.Wallet