fix: Improve gentx validation & error messages (#11500)

## Description

Closes: #9304 



---

### Author Checklist

*All items are required. Please add a note to the item if the item is not applicable and
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

*All items are required. Please add a note if the item is not applicable and please add
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
 
+* (x/genutil) [\#11500](https://github.com/cosmos/cosmos-sdk/pull/11500) Fix GenTx validation and adjust error messages
 * [\#11430](https://github.com/cosmos/cosmos-sdk/pull/11430) Introduce a new `grpc-only` flag, such that when enabled, will start the node in a query-only mode. Note, gRPC MUST be enabled with this flag.
 * (x/upgrade) [\#11116](https://github.com/cosmos/cosmos-sdk/pull/11116) `MsgSoftwareUpgrade` and  has been added to support v1beta2 msgs-based gov proposals.
 * (x/bank) [\#11417](https://github.com/cosmos/cosmos-sdk/pull/11417) Introduce a new `SpendableBalances` gRPC query that retrieves an account's total (paginated) spendable balances.

x/genutil/collect.go

@@ -111,8 +111,8 @@ func CollectTxs(cdc codec.JSONCodec, txJSONDecoder sdk.TxDecoder, moniker, genTx
 			return appGenTxs, persistentPeers, err
 		}
 
-		var genTx sdk.Tx
-		if genTx, err = txJSONDecoder(jsonRawTx); err != nil {
+		genTx, err := types.ValidateAndGetGenTx(jsonRawTx, txJSONDecoder)
+		if err != nil {
 			return appGenTxs, persistentPeers, err
 		}
 

x/genutil/gentx.go

@@ -100,17 +100,17 @@ func DeliverGenTxs(
 	for _, genTx := range genTxs {
 		tx, err := txEncodingConfig.TxJSONDecoder()(genTx)
 		if err != nil {
-			panic(err)
+			return nil, fmt.Errorf("failed to decode GenTx '%s': %s", genTx, err)
 		}
 
 		bz, err := txEncodingConfig.TxEncoder()(tx)
 		if err != nil {
-			panic(err)
+			return nil, fmt.Errorf("failed to encode GenTx '%s': %s", genTx, err)
 		}
 
 		res := deliverTx(abci.RequestDeliverTx{Tx: bz})
 		if !res.IsOK() {
-			panic(res.Log)
+			return nil, fmt.Errorf("failed to execute DelverTx for '%s': %s", genTx, res.Log)
 		}
 	}
 

x/genutil/gentx_test.go

@@ -269,12 +269,12 @@ func (suite *GenTxTestSuite) TestDeliverGenTxs() {
 					)
 				})
 			} else {
-				suite.Require().Panics(func() {
-					genutil.DeliverGenTxs(
+				_, err := genutil.DeliverGenTxs(
 					suite.ctx, genTxs, suite.app.StakingKeeper, suite.app.BaseApp.DeliverTx,
 					suite.encodingConfig.TxConfig,
 				)
-				})
+
+				suite.Require().Error(err)
 			}
 		})
 	}

x/genutil/types/genesis_state.go

@@ -2,7 +2,6 @@ package types
 
 import (
 	"encoding/json"
-	"errors"
 	"fmt"
 
 	tmos "github.com/tendermint/tendermint/libs/os"
@@ -96,24 +95,36 @@ func GenesisStateFromGenFile(genFile string) (genesisState map[string]json.RawMe
 
 // ValidateGenesis validates GenTx transactions
 func ValidateGenesis(genesisState *GenesisState, txJSONDecoder sdk.TxDecoder) error {
-	for i, genTx := range genesisState.GenTxs {
-		var tx sdk.Tx
-		tx, err := txJSONDecoder(genTx)
+	for _, genTx := range genesisState.GenTxs {
+		_, err := ValidateAndGetGenTx(genTx, txJSONDecoder)
 		if err != nil {
 			return err
 		}
-
-		msgs := tx.GetMsgs()
-		if len(msgs) != 1 {
-			return errors.New(
-				"must provide genesis Tx with exactly 1 CreateValidator message")
-		}
-
-		// TODO: abstract back to staking
-		if _, ok := msgs[0].(*stakingtypes.MsgCreateValidator); !ok {
-			return fmt.Errorf(
-				"genesis transaction %v does not contain a MsgCreateValidator", i)
-		}
 	}
 	return nil
 }
+
+// ValidateAndGetGenTx validates the genesis transaction and returns GenTx if valid
+// it cannot verify the signature as it is stateless validation
+func ValidateAndGetGenTx(genTx json.RawMessage, txJSONDecoder sdk.TxDecoder) (sdk.Tx, error) {
+	tx, err := txJSONDecoder(genTx)
+	if err != nil {
+		return tx, fmt.Errorf("failed to decode gentx: %s, error: %s", genTx, err)
+	}
+
+	msgs := tx.GetMsgs()
+	if len(msgs) != 1 {
+		return tx, fmt.Errorf("unexpected number of GenTx messages; got: %d, expected: 1", len(msgs))
+	}
+
+	// TODO: abstract back to staking
+	if _, ok := msgs[0].(*stakingtypes.MsgCreateValidator); !ok {
+		return tx, fmt.Errorf("unexpected GenTx message type; expected: MsgCreateValidator, got: %T", msgs[0])
+	}
+
+	if err := msgs[0].ValidateBasic(); err != nil {
+		return tx, fmt.Errorf("invalid GenTx '%s': %s", msgs[0], err)
+	}
+
+	return tx, nil
+}