cli: cancel transaction command

CLI side method for canceling not yet accepted transaction. It's
alternative to unsupported `canceltransaction` RPC method.

Close #3151.

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

cli/util/cancel.go

@@ -0,0 +1,74 @@
+package util
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/nspcc-dev/neo-go/cli/flags"
+	"github.com/nspcc-dev/neo-go/cli/options"
+	"github.com/nspcc-dev/neo-go/cli/smartcontract"
+	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient/actor"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
+	"github.com/urfave/cli"
+)
+
+func cancelTx(ctx *cli.Context) error {
+	args := ctx.Args()
+	if len(args) == 0 {
+		return cli.NewExitError("transaction hash is missing", 1)
+	} else if len(args) > 1 {
+		return cli.NewExitError("only one transaction hash is accepted", 1)
+	}
+
+	txHash, err := util.Uint256DecodeStringLE(strings.TrimPrefix(args[0], "0x"))
+	if err != nil {
+		return cli.NewExitError(fmt.Sprintf("invalid tx hash: %s", args[0]), 1)
+	}
+
+	gctx, cancel := options.GetTimeoutContext(ctx)
+	defer cancel()
+
+	c, err := options.GetRPCClient(gctx, ctx)
+	if err != nil {
+		return cli.NewExitError(fmt.Errorf("failed to create RPC client: %w", err), 1)
+	}
+
+	mainTx, _ := c.GetRawTransactionVerbose(txHash)
+	if mainTx != nil && !mainTx.Blockhash.Equals(util.Uint256{}) {
+		return cli.NewExitError(fmt.Errorf("transaction %s is already accepted at block %s", txHash, mainTx.Blockhash.StringLE()), 1)
+	}
+	acc, w, err := smartcontract.GetAccFromContext(ctx)
+	if err != nil {
+		return cli.NewExitError(fmt.Errorf("failed to get account from context to sign the conflicting transaction: %w", err), 1)
+	}
+	defer w.Close()
+
+	if mainTx != nil && !mainTx.HasSigner(acc.ScriptHash()) {
+		return cli.NewExitError(fmt.Errorf("account %s is not a signer of the conflicting transaction", acc.Address), 1)
+	}
+
+	a, err := actor.NewSimple(c, acc)
+	if err != nil {
+		return cli.NewExitError(fmt.Errorf("failed to create Actor: %w", err), 1)
+	}
+
+	resHash, _, err := a.SendTunedRun([]byte{byte(opcode.RET)}, []transaction.Attribute{{Type: transaction.ConflictsT, Value: &transaction.Conflicts{Hash: txHash}}}, func(r *result.Invoke, t *transaction.Transaction) error {
+		err := actor.DefaultCheckerModifier(r, t)
+		if err != nil {
+			return err
+		}
+		if mainTx != nil && t.NetworkFee < mainTx.NetworkFee+1 {
+			t.NetworkFee = mainTx.NetworkFee + 1
+		}
+		t.NetworkFee += int64(flags.Fixed8FromContext(ctx, "gas"))
+		return nil
+	})
+	if err != nil {
+		return cli.NewExitError(fmt.Errorf("failed to send conflicting transaction: %w", err), 1)
+	}
+	fmt.Fprintln(ctx.App.Writer, resHash.StringLE())
+	return nil
+}

cli/util/convert.go

@@ -6,7 +6,9 @@ import (
 	"fmt"
 	"os"
 
+	"github.com/nspcc-dev/neo-go/cli/flags"
 	"github.com/nspcc-dev/neo-go/cli/options"
+	"github.com/nspcc-dev/neo-go/cli/txctx"
 	vmcli "github.com/nspcc-dev/neo-go/cli/vm"
 	"github.com/nspcc-dev/neo-go/pkg/vm"
 	"github.com/urfave/cli"
@@ -15,6 +17,14 @@ import (
 // NewCommands returns util commands for neo-go CLI.
 func NewCommands() []cli.Command {
 	txDumpFlags := append([]cli.Flag{}, options.RPC...)
+	txCancelFlags := append([]cli.Flag{
+		flags.AddressFlag{
+			Name:  "address, a",
+			Usage: "address to use as conflicting transaction signee (and gas source)",
+		},
+		txctx.GasFlag,
+	}, options.RPC...)
+	txCancelFlags = append(txCancelFlags, options.Wallet...)
 	return []cli.Command{
 		{
 			Name:  "util",
@@ -41,6 +51,24 @@ func NewCommands() []cli.Command {
 					Action: sendTx,
 					Flags:  txDumpFlags,
 				},
+				{
+					Name:      "canceltx",
+					Usage:     "Cancel transaction by sending conflicting transaction",
+					UsageText: "canceltx <txid> -r <endpoint> --wallet <wallet> [--account <account>] [--wallet-config <path>] [--gas <gas>]",
+					Description: `Aims to prevent a transaction from being added to the blockchain by dispatching a more 
+prioritized conflicting transaction to the specified RPC node. The input for this command should 
+be the transaction hash. If another account is not specified, the conflicting transaction is 
+automatically generated and signed by the default account in the wallet. If the target transaction 
+is in the memory pool of the provided RPC node, the NetworkFee value of the conflicting transaction 
+is set to the target transaction's NetworkFee value plus one (if it's sufficient for the 
+conflicting transaction itself). If the target transaction is not in the memory pool, standard 
+NetworkFee calculations are performed based on the calculatenetworkfee RPC request. If the --gas 
+flag is included, the specified value is added to the resulting conflicting transaction network fee 
+in both scenarios.
+`,
+					Action: cancelTx,
+					Flags:  txCancelFlags,
+				},
 				{
 					Name:      "txdump",
 					Usage:     "Dump transaction stored in file",

cli/util/util_test.go

@@ -4,9 +4,12 @@ import (
 	"os"
 	"path/filepath"
 	"testing"
+	"time"
 
 	"github.com/nspcc-dev/neo-go/internal/testcli"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger"
 	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/wallet"
 	"github.com/stretchr/testify/require"
 )
 
@@ -63,3 +66,73 @@ func TestUtilOps(t *testing.T) {
 	e.Run(t, "neo-go", "util", "ops", "--hex", "--in", tmp) // hex from file
 	check(t)
 }
+
+func TestUtilCancelTx(t *testing.T) {
+	e := testcli.NewExecutorSuspended(t)
+
+	w, err := wallet.NewWalletFromFile("../testdata/testwallet.json")
+	require.NoError(t, err)
+
+	transferArgs := []string{
+		"neo-go", "wallet", "nep17", "transfer",
+		"--rpc-endpoint", "http://" + e.RPC.Addresses()[0],
+		"--wallet", testcli.ValidatorWallet,
+		"--to", w.Accounts[0].Address,
+		"--token", "NEO",
+		"--from", testcli.ValidatorAddr,
+		"--force",
+	}
+	args := []string{"neo-go", "util", "canceltx",
+		"-r", "http://" + e.RPC.Addresses()[0],
+		"--wallet", testcli.ValidatorWallet,
+		"--address", testcli.ValidatorAddr}
+
+	e.In.WriteString("one\r")
+	e.Run(t, append(transferArgs, "--amount", "1")...)
+	line := e.GetNextLine(t)
+	txHash, err := util.Uint256DecodeStringLE(line)
+	require.NoError(t, err)
+
+	_, ok := e.Chain.GetMemPool().TryGetValue(txHash)
+	require.True(t, ok)
+
+	t.Run("invalid", func(t *testing.T) {
+		t.Run("missing tx argument", func(t *testing.T) {
+			e.RunWithError(t, args...)
+		})
+		t.Run("excessive arguments", func(t *testing.T) {
+			e.RunWithError(t, append(args, txHash.StringLE(), txHash.StringLE())...)
+		})
+		t.Run("invalid hash", func(t *testing.T) {
+			e.RunWithError(t, append(args, "notahash")...)
+		})
+		t.Run("not signed by main signer", func(t *testing.T) {
+			e.In.WriteString("one\r")
+			e.RunWithError(t, "neo-go", "util", "canceltx",
+				"-r", "http://"+e.RPC.Addresses()[0],
+				"--wallet", testcli.ValidatorWallet,
+				"--address", testcli.MultisigAddr, txHash.StringLE())
+		})
+		t.Run("wrong rpc endpoint", func(t *testing.T) {
+			e.In.WriteString("one\r")
+			e.RunWithError(t, "neo-go", "util", "canceltx",
+				"-r", "http://localhost:20331",
+				"--wallet", testcli.ValidatorWallet, txHash.StringLE())
+		})
+	})
+
+	e.In.WriteString("one\r")
+	e.Run(t, append(args, txHash.StringLE())...)
+	resHash, err := util.Uint256DecodeStringLE(e.GetNextLine(t))
+	require.NoError(t, err)
+
+	_, _, err = e.Chain.GetTransaction(resHash)
+	require.NoError(t, err)
+	e.CheckEOF(t)
+	go e.Chain.Run()
+
+	require.Eventually(t, func() bool {
+		_, aerErr := e.Chain.GetAppExecResults(resHash, trigger.Application)
+		return aerErr == nil
+	}, time.Second*2, time.Millisecond*50)
+}

docs/rpc.md

@@ -214,7 +214,7 @@ and we're not accepting issues related to them.
 
 | Method  | Reason |
 | ------- | ------------|
-| `canceltransaction` | Doesn't fit neo-go wallet model |
+| `canceltransaction` | Doesn't fit neo-go wallet model, use CLI to do that (`neo-go util canceltx`) |
 | `closewallet` | Doesn't fit neo-go wallet model |
 | `dumpprivkey` | Shouldn't exist for security reasons, see `closewallet` comment also |
 | `getnewaddress` | See `closewallet` comment, use CLI to do that |