feat(x/bank/cli)!: Allow MultiSendTx to Support Transactions with a Single Recipient

x/bank/CHANGELOG.md

@@ -29,6 +29,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 * [#17569](https://github.com/cosmos/cosmos-sdk/pull/17569) Introduce a new message type, `MsgBurn`, to burn coins.
 * [#20014](https://github.com/cosmos/cosmos-sdk/pull/20014) Support app wiring for `SendRestrictionFn`.
+* [#21920](https://github.com/cosmos/cosmos-sdk/pull/21920) Allow `MultiSendTx` to support transactions with a single recipient.
 
 ### Improvements
 

x/bank/client/cli/tx.go

@@ -36,21 +36,21 @@ func NewTxCmd() *cobra.Command {
 }
 
 // NewMultiSendTxCmd returns a CLI command handler for creating a MsgMultiSend transaction.
-// For a better UX this command is limited to send funds from one account to two or more accounts.
+// This version allows sending funds from one account to one or more accounts.
 func NewMultiSendTxCmd() *cobra.Command {
 	cmd := &cobra.Command{
-		Use:   "multi-send <from_key_or_address> <to_address_1> <to_address_2>... <amount>",
-		Short: "Send funds from one account to two or more accounts.",
-		Long: `Send funds from one account to two or more accounts.
-By default, sends the [amount] to each address of the list.
+		Use:   "multi-send <from_key_or_address> <to_address_1>... <amount>",
+		Short: "Send funds from one account to one or more accounts.",
+		Long: `Send funds from one account to one or more accounts.
+By default, sends the [amount] to each address in the list.
 Using the '--split' flag, the [amount] is split equally between the addresses.
-Note, the '--from' flag is ignored as it is implied from [from_key_or_address] and 
+Note, the '--from' flag is ignored as it is implied from [from_key_or_address] and
 separate addresses with space.
 When using '--dry-run' a key name cannot be used, only a bech32 address.`,
-		Example: fmt.Sprintf("%s tx bank multi-send cosmos1... cosmos1... cosmos1... cosmos1... 10stake", version.AppName),
-		Args:    cobra.MinimumNArgs(4),
+		Example: fmt.Sprintf("%s tx bank multi-send cosmos1... cosmos1... cosmos1... 10stake", version.AppName),
+		Args:    cobra.MinimumNArgs(3), // Changed minimum argument count to 3
 		RunE: func(cmd *cobra.Command, args []string) error {
-			err := cmd.Flags().Set(flags.FlagFrom, args[0])
+			err := cmd.Flags().Set(flags.FlagFrom, args[0]) // Set the first argument as the sender
 			if err != nil {
 				return err
 			}
@@ -59,7 +59,7 @@ When using '--dry-run' a key name cannot be used, only a bech32 address.`,
 				return err
 			}
 
-			coins, err := sdk.ParseCoinsNormalized(args[len(args)-1])
+			coins, err := sdk.ParseCoinsNormalized(args[len(args)-1]) // The last argument is the amount
 			if err != nil {
 				return err
 			}
@@ -73,15 +73,15 @@ When using '--dry-run' a key name cannot be used, only a bech32 address.`,
 				return err
 			}
 
-			totalAddrs := sdkmath.NewInt(int64(len(args) - 2))
+			totalAddrs := sdkmath.NewInt(int64(len(args) - 2)) // Calculate the number of recipients
 			// coins to be received by the addresses
 			sendCoins := coins
 			if split {
-				sendCoins = coins.QuoInt(totalAddrs)
+				sendCoins = coins.QuoInt(totalAddrs) // Logic to split the amount among recipients
 			}
 
 			var output []types.Output
-			for _, arg := range args[1 : len(args)-1] {
+			for _, arg := range args[1 : len(args)-1] { // Process each recipient
 				_, err = clientCtx.AddressCodec.StringToBytes(arg)
 				if err != nil {
 					return err
@@ -90,11 +90,9 @@ When using '--dry-run' a key name cannot be used, only a bech32 address.`,
 				output = append(output, types.NewOutput(arg, sendCoins))
 			}
 
-			// amount to be send from the from address
+			// Calculate the total amount to be sent by the sender
 			var amount sdk.Coins
 			if split {
-				// user input: 1000stake to send to 3 addresses
-				// actual: 333stake to each address (=> 999stake actually sent)
 				amount = sendCoins.MulInt(totalAddrs)
 			} else {
 				amount = coins.MulInt(totalAddrs)

x/bank/client/cli/tx_test.go

@@ -51,7 +51,127 @@ func (s *CLITestSuite) SetupSuite() {
 		WithConsensusAddressCodec(addresscodec.NewBech32Codec("cosmosvalcons"))
 }
 
-func (s *CLITestSuite) TestMultiSendTxCmd() {
+func (s *CLITestSuite) TestMultiSendTxCmd_SingleRecipient() {
+	accounts := testutil.CreateKeyringAccounts(s.T(), s.kr, 2) // Create only 2 accounts: one sender and one recipient
+	accountStr := make([]string, len(accounts))
+	for i, acc := range accounts {
+		addrStr, err := s.baseCtx.AddressCodec.BytesToString(acc.Address)
+		s.Require().NoError(err)
+		accountStr[i] = addrStr
+	}
+
+	cmd := cli.NewMultiSendTxCmd()
+	cmd.SetOutput(io.Discard)
+
+	extraArgs := []string{
+		fmt.Sprintf("--%s=%s", flags.FlagBroadcastMode, flags.BroadcastSync),
+		fmt.Sprintf("--%s=true", flags.FlagSkipConfirmation),
+		fmt.Sprintf("--%s=%s", flags.FlagBroadcastMode, flags.BroadcastSync),
+		fmt.Sprintf("--%s=%s", flags.FlagFees, sdk.NewCoins(sdk.NewCoin("photon", sdkmath.NewInt(10))).String()),
+		fmt.Sprintf("--%s=test-chain", flags.FlagChainID),
+	}
+
+	testCases := []struct {
+		name         string
+		ctxGen       func() client.Context
+		from         string
+		to           []string
+		amount       sdk.Coins
+		extraArgs    []string
+		expectErrMsg string
+	}{
+		{
+			"valid transaction with single recipient",
+			func() client.Context {
+				return s.baseCtx
+			},
+			accountStr[0], // Sending account
+			[]string{
+				accountStr[1], // Only one recipient account
+			},
+			sdk.NewCoins(
+				sdk.NewCoin("stake", sdkmath.NewInt(10)),
+				sdk.NewCoin("photon", sdkmath.NewInt(40)),
+			),
+			extraArgs,
+			"",
+		},
+		{
+			"invalid from Address",
+			func() client.Context {
+				return s.baseCtx
+			},
+			"foo",
+			[]string{
+				accountStr[1],
+			},
+			sdk.NewCoins(
+				sdk.NewCoin("stake", sdkmath.NewInt(10)),
+				sdk.NewCoin("photon", sdkmath.NewInt(40)),
+			),
+			extraArgs,
+			"key not found",
+		},
+		{
+			"invalid recipient",
+			func() client.Context {
+				return s.baseCtx
+			},
+			accountStr[0],
+			[]string{
+				"bar",
+			},
+			sdk.NewCoins(
+				sdk.NewCoin("stake", sdkmath.NewInt(10)),
+				sdk.NewCoin("photon", sdkmath.NewInt(40)),
+			),
+			extraArgs,
+			"invalid bech32 string",
+		},
+		{
+			"invalid amount",
+			func() client.Context {
+				return s.baseCtx
+			},
+			accountStr[0],
+			[]string{
+				accountStr[1],
+			},
+			nil,
+			extraArgs,
+			"must send positive amount",
+		},
+	}
+
+	for _, tc := range testCases {
+		s.Run(tc.name, func() {
+			ctx := svrcmd.CreateExecuteContext(context.Background())
+
+			var args []string
+			args = append(args, tc.from)            // Sending account
+			args = append(args, tc.to...)           // Recipient account(s)
+			args = append(args, tc.amount.String()) // Amount
+			args = append(args, tc.extraArgs...)    // Additional flags
+
+			cmd.SetContext(ctx)
+			cmd.SetArgs(args)
+
+			s.Require().NoError(client.SetCmdClientContextHandler(tc.ctxGen(), cmd))
+
+			out, err := clitestutil.ExecTestCLICmd(tc.ctxGen(), cmd, args)
+			if tc.expectErrMsg != "" {
+				s.Require().Error(err)
+				s.Require().Contains(out.String(), tc.expectErrMsg)
+			} else {
+				s.Require().NoError(err)
+				msg := &sdk.TxResponse{}
+				s.Require().NoError(tc.ctxGen().Codec.UnmarshalJSON(out.Bytes(), msg), out.String())
+			}
+		})
+	}
+}
+
+func (s *CLITestSuite) TestMultiSendTxCmd_MultiRecipient() {
 	accounts := testutil.CreateKeyringAccounts(s.T(), s.kr, 3)
 	accountStr := make([]string, len(accounts))
 	for i, acc := range accounts {