wallet: make --wif optional in import-multisig command

We have a full list of public keys in the import-multisig command, so if
 we have a key in the wallet that corresponds to one of these keys
 (simple sig), just reuse it for the account automatically

Closes #3266

Signed-off-by: Ekaterina Pavlova <ekt@morphbits.io>

cli/wallet/wallet.go

@@ -236,8 +236,15 @@ func NewCommands() []cli.Command {
 			{
 				Name:  "import-multisig",
 				Usage: "import multisig contract",
-				UsageText: "import-multisig -w wallet [--wallet-config path] --wif <wif> [--name <account_name>] --min <n>" +
+				UsageText: "import-multisig -w wallet [--wallet-config path] [--wif <wif>] [--name <account_name>] --min <m>" +
 					" [<pubkey1> [<pubkey2> [...]]]",
+				Description: `Imports a standard multisignature contract with "m out of n" signatures required where "m" is
+       specified by --min flag and "n" is the length of provided set of public keys. If
+       --wif flag is provided, it's used to create an account with the given name (or
+       without a name if --name flag is not provided). Otherwise, the command tries to
+       find an account with one of the given public keys and convert it to multisig. If
+       no suitable account is found and no --wif flag is specified, an error is returned.
+`,
 				Action: importMultisig,
 				Flags: []cli.Flag{
 					walletPathFlag,
@@ -521,6 +528,12 @@ loop:
 }
 
 func importMultisig(ctx *cli.Context) error {
+	var (
+		label  *string
+		acc    *wallet.Account
+		accPub *keys.PublicKey
+	)
+
 	wall, pass, err := openWallet(ctx, true)
 	if err != nil {
 		return cli.NewExitError(err, 1)
@@ -542,12 +555,45 @@ func importMultisig(ctx *cli.Context) error {
 		}
 	}
 
-	var label *string
 	if ctx.IsSet("name") {
 		l := ctx.String("name")
 		label = &l
 	}
-	acc, err := newAccountFromWIF(ctx.App.Writer, ctx.String("wif"), wall.Scrypt, label, pass)
+
+loop:
+	for _, pub := range pubs {
+		for _, wallAcc := range wall.Accounts {
+			if wallAcc.ScriptHash().Equals(pub.GetScriptHash()) {
+				if acc != nil {
+					// Multiple matching accounts found, fallback to WIF-based conversion.
+					acc = nil
+					break loop
+				}
+				acc = new(wallet.Account)
+				*acc = *wallAcc
+				accPub = pub
+			}
+		}
+	}
+
+	if acc != nil {
+		err = acc.ConvertMultisigEncrypted(accPub, m, pubs)
+		if err != nil {
+			return cli.NewExitError(err, 1)
+		}
+		if label != nil {
+			acc.Label = *label
+		}
+		if err := addAccountAndSave(wall, acc); err != nil {
+			return cli.NewExitError(err, 1)
+		}
+		return nil
+	}
+
+	if !ctx.IsSet("wif") {
+		return cli.NewExitError(errors.New("none of the provided public keys correspond to an existing key in the wallet or multiple matching accounts found in the wallet, and no WIF is provided"), 1)
+	}
+	acc, err = newAccountFromWIF(ctx.App.Writer, ctx.String("wif"), wall.Scrypt, label, pass)
 	if err != nil {
 		return cli.NewExitError(err, 1)
 	}

cli/wallet/wallet_test.go

@@ -487,6 +487,58 @@ func TestWalletInit(t *testing.T) {
 					hex.EncodeToString(pubs[2].Bytes()),
 					hex.EncodeToString(pubs[3].Bytes()))...)
 			})
+
+			privs, pubs = testcli.GenerateKeys(t, 3)
+			script, err = smartcontract.CreateMultiSigRedeemScript(2, pubs)
+			require.NoError(t, err)
+			// Create a wallet and import a standard account
+			e.Run(t, "neo-go", "wallet", "init", "--wallet", walletPath)
+			e.In.WriteString("standardacc\rstdpass\rstdpass\r")
+			e.Run(t, "neo-go", "wallet", "import",
+				"--wallet", walletPath,
+				"--wif", privs[0].WIF())
+			w, err = wallet.NewWalletFromFile(walletPath)
+			require.NoError(t, err)
+			actual = w.GetAccount(privs[0].GetScriptHash())
+			require.NotNil(t, actual)
+			require.NotEqual(t, actual.Contract.Script, script)
+
+			// Test when a public key of an already imported account is present
+			t.Run("existing account public key, no WIF", func(t *testing.T) {
+				e.Run(t, "neo-go", "wallet", "import-multisig",
+					"--wallet", walletPath,
+					"--min", "2",
+					hex.EncodeToString(pubs[0].Bytes()), // Public key of the already imported account
+					hex.EncodeToString(pubs[1].Bytes()),
+					hex.EncodeToString(pubs[2].Bytes()))
+
+				w, err := wallet.NewWalletFromFile(walletPath)
+				require.NoError(t, err)
+				actual := w.GetAccount(hash.Hash160(script))
+				require.NotNil(t, actual)
+				require.Equal(t, actual.Contract.Script, script)
+				require.NoError(t, actual.Decrypt("stdpass", w.Scrypt))
+				require.NotEqual(t, actual.Address, w.GetAccount(privs[0].GetScriptHash()).Address)
+			})
+
+			// Test when no public key of an already imported account is present, and no WIF is provided
+			t.Run("no existing account public key, no WIF", func(t *testing.T) {
+				_, pubsNew := testcli.GenerateKeys(t, 3)
+				scriptNew, err := smartcontract.CreateMultiSigRedeemScript(2, pubsNew)
+				require.NoError(t, err)
+
+				e.RunWithError(t, "neo-go", "wallet", "import-multisig",
+					"--wallet", walletPath,
+					"--min", "2",
+					hex.EncodeToString(pubsNew[0].Bytes()),
+					hex.EncodeToString(pubsNew[1].Bytes()),
+					hex.EncodeToString(pubsNew[2].Bytes()))
+
+				w, err := wallet.NewWalletFromFile(walletPath)
+				require.NoError(t, err)
+				actual := w.GetAccount(hash.Hash160(scriptNew))
+				require.Nil(t, actual)
+			})
 		})
 	})
 }

pkg/wallet/account.go

@@ -283,8 +283,15 @@ func (a *Account) ConvertMultisig(m int, pubs []*keys.PublicKey) error {
 	if a.privateKey == nil {
 		return errors.New("account key is not available (need to decrypt?)")
 	}
-	var found bool
 	accKey := a.privateKey.PublicKey()
+	return a.ConvertMultisigEncrypted(accKey, m, pubs)
+}
+
+// ConvertMultisigEncrypted sets a's contract to an encrypted multisig contract
+// with m sufficient signatures. The encrypted private key is not modified and
+// remains the same.
+func (a *Account) ConvertMultisigEncrypted(accKey *keys.PublicKey, m int, pubs []*keys.PublicKey) error {
+	var found bool
 	for i := range pubs {
 		if accKey.Equal(pubs[i]) {
 			found = true