feat: tx with generate-only and offline shouldn't use chain id (#10710)

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## Description
chain-id shouldn't be required for creating a tx with --generate-only and --offline 

ref: #9407 

---

### Author Checklist

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please add links to any relevant follow up issues.*

I have...

- [ ] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] added `!` to the type prefix if API or client breaking change
- [ ] targeted the correct branch (see [PR Targeting](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#pr-targeting))
- [ ] provided a link to the relevant issue or specification
- [ ] followed the guidelines for [building modules](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules)
- [ ] included the necessary unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#testing)
- [ ] added a changelog entry to `CHANGELOG.md`
- [ ] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [ ] updated the relevant documentation or specification
- [ ] reviewed "Files changed" and left comments if necessary
- [ ] confirmed all CI checks have passed

### Reviewers Checklist

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your handle next to the items reviewed if you only reviewed selected items.*

I have...

- [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] confirmed `!` in the type prefix if API or client breaking change
- [ ] confirmed all author checklist items have been addressed 
- [ ] reviewed state machine logic
- [ ] reviewed API design and naming
- [ ] reviewed documentation is accurate
- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)

CHANGELOG.md

@@ -39,6 +39,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Features
 
+* [\#10710](https://github.com/cosmos/cosmos-sdk/pull/10710) Chain-id shouldn't be required for creating a transaction with both --generate-only and --offline flags.
 * [\#10703](https://github.com/cosmos/cosmos-sdk/pull/10703) Create a new grantee account, if the grantee of an authorization does not exist.
 * [\#10592](https://github.com/cosmos/cosmos-sdk/pull/10592) Add a `DecApproxEq` function that checks to see if `|d1 - d2| < tol` for some Dec `d1, d2, tol`.
 * [\#10393](https://github.com/cosmos/cosmos-sdk/pull/10393) Add `HasSupply` method to bank keeper to ensure that input denom actually exists on chain.

client/tx/factory.go

@@ -28,6 +28,8 @@ type Factory struct {
 	timeoutHeight      uint64
 	gasAdjustment      float64
 	chainID            string
+	offline            bool
+	generateOnly       bool
 	memo               string
 	fees               sdk.Coins
 	tip                *tx.Tip
@@ -64,6 +66,8 @@ func NewFactoryCLI(clientCtx client.Context, flagSet *pflag.FlagSet) Factory {
 		accountRetriever:   clientCtx.AccountRetriever,
 		keybase:            clientCtx.Keyring,
 		chainID:            clientCtx.ChainID,
+		offline:            clientCtx.Offline,
+		generateOnly:       clientCtx.GenerateOnly,
 		gas:                gasSetting.Gas,
 		simulateAndExecute: gasSetting.Simulate,
 		accountNumber:      accNum,
@@ -220,7 +224,11 @@ func (f Factory) WithTimeoutHeight(height uint64) Factory {
 // BuildUnsignedTx builds a transaction to be signed given a set of messages.
 // Once created, the fee, memo, and messages are set.
 func (f Factory) BuildUnsignedTx(msgs ...sdk.Msg) (client.TxBuilder, error) {
-	if f.chainID == "" {
+	if f.offline && f.generateOnly {
+		if f.chainID != "" {
+			return nil, fmt.Errorf("chain ID cannot be used when offline and generate-only flags are set")
+		}
+	} else if f.chainID == "" {
 		return nil, fmt.Errorf("chain ID required but not specified")
 	}
 

x/bank/client/testutil/suite.go

@@ -414,6 +414,23 @@ func (s *IntegrationTestSuite) TestNewSendTxCmd() {
 			},
 			false, 0, &sdk.TxResponse{},
 		},
+		{
+			"chain-id shouldn't be used with offline and generate-only flags",
+			val.Address,
+			val.Address,
+			sdk.NewCoins(
+				sdk.NewCoin(fmt.Sprintf("%stoken", val.Moniker), sdk.NewInt(10)),
+				sdk.NewCoin(s.cfg.BondDenom, sdk.NewInt(10)),
+			),
+			[]string{
+				fmt.Sprintf("--%s=true", flags.FlagSkipConfirmation),
+				fmt.Sprintf("--%s=%s", flags.FlagBroadcastMode, flags.BroadcastSync),
+				fmt.Sprintf("--%s=%s", flags.FlagFees, sdk.NewCoins(sdk.NewCoin(s.cfg.BondDenom, sdk.NewInt(10))).String()),
+				fmt.Sprintf("--%s=true", flags.FlagOffline),
+				fmt.Sprintf("--%s=true", flags.FlagGenerateOnly),
+			},
+			true, 0, &sdk.TxResponse{},
+		},
 		{
 			"not enough fees",
 			val.Address,