Merge PR #4384: allow splitting withdrawal txs

* allow splitting withdrawal txs

* updating .pending

* small cleanup

* fixing build issue

* Update x/distribution/client/cli/tx.go

Co-Authored-By: Alessio Treglia <quadrispro@ubuntu.com>

* updating usage text

* fixing merge issue

* changes based on the review

* adding unit tests

* Update x/distribution/client/cli/tx.go

Co-Authored-By: Alexander Bezobchuk <alexanderbez@users.noreply.github.com>

* adjustments from review

.pending/improvements/sdk/4384-WithdrawalTxSplitting

@@ -0,0 +1 @@
+#4384- Allow splitting withdrawal transaction in several chunks

x/distribution/client/cli/tx.go

@@ -26,6 +26,11 @@ var (
 	flagOnlyFromValidator = "only-from-validator"
 	flagIsValidator       = "is-validator"
 	flagComission         = "commission"
+	flagMaxMessagesPerTx  = "max-msgs"
+)
+
+const (
+	MaxMessagesPerTxDefault = 5
 )
 
 // GetTxCmd returns the transaction commands for this module
@@ -43,6 +48,38 @@ func GetTxCmd(storeKey string, cdc *amino.Codec) *cobra.Command {
 	return distTxCmd
 }
 
+type generateOrBroadcastFunc func(context.CLIContext, authtxb.TxBuilder, []sdk.Msg) error
+
+func splitAndApply(
+	generateOrBroadcast generateOrBroadcastFunc,
+	cliCtx context.CLIContext,
+	txBldr authtxb.TxBuilder,
+	msgs []sdk.Msg,
+	chunkSize int,
+) error {
+
+	if chunkSize == 0 {
+		return generateOrBroadcast(cliCtx, txBldr, msgs)
+	}
+
+	// split messages into slices of length chunkSize
+	totalMessages := len(msgs)
+	for i := 0; i < len(msgs); i += chunkSize {
+
+		sliceEnd := i + chunkSize
+		if sliceEnd > totalMessages {
+			sliceEnd = totalMessages
+		}
+
+		msgChunk := msgs[i:sliceEnd]
+		if err := generateOrBroadcast(cliCtx, txBldr, msgChunk); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 // command to withdraw rewards
 func GetCmdWithdrawRewards(cdc *codec.Codec) *cobra.Command {
 	cmd := &cobra.Command{
@@ -86,7 +123,7 @@ $ %s tx distr withdraw-rewards cosmosvaloper1gghjut3ccd8ay0zduzj64hwre2fxs9ldmqh
 
 // command to withdraw all rewards
 func GetCmdWithdrawAllRewards(cdc *codec.Codec, queryRoute string) *cobra.Command {
-	return &cobra.Command{
+	cmd := &cobra.Command{
 		Use:   "withdraw-all-rewards",
 		Short: "withdraw all delegations rewards for a delegator",
 		Long: strings.TrimSpace(
@@ -112,14 +149,17 @@ $ %s tx distr withdraw-all-rewards --from mykey
 				return err
 			}
 
-			return utils.GenerateOrBroadcastMsgs(cliCtx, txBldr, msgs)
+			chunkSize := viper.GetInt(flagMaxMessagesPerTx)
+			return splitAndApply(utils.GenerateOrBroadcastMsgs, cliCtx, txBldr, msgs, chunkSize)
 		},
 	}
+	cmd.Flags().Int(flagMaxMessagesPerTx, MaxMessagesPerTxDefault, "Limit the number of messages per tx (0 for unlimited)")
+	return cmd
 }
 
 // command to replace a delegator's withdrawal address
 func GetCmdSetWithdrawAddr(cdc *codec.Codec) *cobra.Command {
-	cmd := &cobra.Command{
+	return &cobra.Command{
 		Use:   "set-withdraw-addr [withdraw-addr]",
 		Short: "change the default withdraw address for rewards associated with an address",
 		Long: strings.TrimSpace(
@@ -149,7 +189,6 @@ $ %s tx set-withdraw-addr cosmos1gghjut3ccd8ay0zduzj64hwre2fxs9ld75ru9p --from m
 			return utils.GenerateOrBroadcastMsgs(cliCtx, txBldr, []sdk.Msg{msg})
 		},
 	}
-	return cmd
 }
 
 // GetCmdSubmitProposal implements the command to submit a community-pool-spend proposal

x/distribution/client/cli/tx_test.go

@@ -0,0 +1,77 @@
+package cli
+
+import (
+	"github.com/cosmos/cosmos-sdk/client/context"
+	"github.com/cosmos/cosmos-sdk/client/utils"
+	"github.com/cosmos/cosmos-sdk/codec"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	authtxb "github.com/cosmos/cosmos-sdk/x/auth/client/txbuilder"
+	"github.com/stretchr/testify/assert"
+	"github.com/tendermint/tendermint/crypto/secp256k1"
+	"testing"
+)
+
+func createFakeTxBuilder() authtxb.TxBuilder {
+	cdc := codec.New()
+	return authtxb.NewTxBuilder(
+		utils.GetTxEncoder(cdc),
+		123,
+		9876,
+		0,
+		1.2,
+		false,
+		"test_chain",
+		"hello",
+		sdk.NewCoins(sdk.NewCoin(sdk.DefaultBondDenom, sdk.NewInt(1))),
+		sdk.DecCoins{sdk.NewDecCoinFromDec(sdk.DefaultBondDenom, sdk.NewDecWithPrec(10000, sdk.Precision))},
+	)
+}
+
+func Test_splitAndCall_NoMessages(t *testing.T) {
+	ctx := context.CLIContext{}
+	txBldr := createFakeTxBuilder()
+
+	err := splitAndApply(nil, ctx, txBldr, nil, 10)
+	assert.NoError(t, err, "")
+}
+
+func Test_splitAndCall_Splitting(t *testing.T) {
+	ctx := context.CLIContext{}
+	txBldr := createFakeTxBuilder()
+
+	addr := sdk.AccAddress(secp256k1.GenPrivKey().PubKey().Address())
+
+	// Add five messages
+	msgs := []sdk.Msg{
+		sdk.NewTestMsg(addr),
+		sdk.NewTestMsg(addr),
+		sdk.NewTestMsg(addr),
+		sdk.NewTestMsg(addr),
+		sdk.NewTestMsg(addr),
+	}
+
+	// Keep track of number of calls
+	const chunkSize = 2
+
+	callCount := 0
+	err := splitAndApply(
+		func(ctx context.CLIContext, txBldr authtxb.TxBuilder, msgs []sdk.Msg) error {
+			callCount += 1
+
+			assert.NotNil(t, ctx)
+			assert.NotNil(t, txBldr)
+			assert.NotNil(t, msgs)
+
+			if callCount < 3 {
+				assert.Equal(t, len(msgs), 2)
+			} else {
+				assert.Equal(t, len(msgs), 1)
+			}
+
+			return nil
+		},
+		ctx, txBldr, msgs, chunkSize)
+
+	assert.NoError(t, err, "")
+	assert.Equal(t, 3, callCount)
+}