fix!: Remove onlyAminoSigners in sequence check (#10029)

## Description

Amino multisig update. It breaks the state machine and it's needed for the next SDK upgrade.

---

### 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...

- [x] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [x] added `!` to the type prefix if API or client breaking change
- [x] 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)

client/tx/legacy.go

@@ -5,7 +5,6 @@ import (
 
 	"github.com/cosmos/cosmos-sdk/client"
 	"github.com/cosmos/cosmos-sdk/codec"
-	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 	"github.com/cosmos/cosmos-sdk/x/auth/signing"
 )
@@ -65,24 +64,3 @@ func CopyTx(tx signing.Tx, builder client.TxBuilder, ignoreSignatureError bool)
 
 	return nil
 }
-
-// ConvertAndEncodeStdTx encodes the stdTx as a transaction in the format specified by txConfig
-func ConvertAndEncodeStdTx(txConfig client.TxConfig, stdTx legacytx.StdTx) ([]byte, error) {
-	builder := txConfig.NewTxBuilder()
-
-	var theTx sdk.Tx
-
-	// check if we need a StdTx anyway, in that case don't copy
-	if _, ok := builder.GetTx().(legacytx.StdTx); ok {
-		theTx = stdTx
-	} else {
-		err := CopyTx(stdTx, builder, false)
-		if err != nil {
-			return nil, err
-		}
-
-		theTx = builder.GetTx()
-	}
-
-	return txConfig.TxEncoder()(theTx)
-}

client/tx/legacy_test.go

@@ -15,7 +15,6 @@ import (
 	"github.com/cosmos/cosmos-sdk/types"
 	signing2 "github.com/cosmos/cosmos-sdk/types/tx/signing"
 	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
-	"github.com/cosmos/cosmos-sdk/x/auth/signing"
 	"github.com/cosmos/cosmos-sdk/x/auth/tx"
 	banktypes "github.com/cosmos/cosmos-sdk/x/bank/types"
 )
@@ -149,27 +148,6 @@ func (s *TestSuite) TestConvertTxToStdTx() {
 	s.Require().Equal(stdTx, stdTx2)
 }
 
-func (s *TestSuite) TestConvertAndEncodeStdTx() {
-	// convert amino -> proto -> amino
-	aminoBuilder := s.aminoCfg.NewTxBuilder()
-	buildTestTx(s.T(), aminoBuilder)
-	stdTx := aminoBuilder.GetTx().(legacytx.StdTx)
-	txBz, err := tx2.ConvertAndEncodeStdTx(s.protoCfg, stdTx)
-	s.Require().NoError(err)
-	decodedTx, err := s.protoCfg.TxDecoder()(txBz)
-	s.Require().NoError(err)
-	aminoBuilder2 := s.aminoCfg.NewTxBuilder()
-	s.Require().NoError(tx2.CopyTx(decodedTx.(signing.Tx), aminoBuilder2, false))
-	s.Require().Equal(stdTx, aminoBuilder2.GetTx())
-
-	// just use amino everywhere
-	txBz, err = tx2.ConvertAndEncodeStdTx(s.aminoCfg, stdTx)
-	s.Require().NoError(err)
-	decodedTx, err = s.aminoCfg.TxDecoder()(txBz)
-	s.Require().NoError(err)
-	s.Require().Equal(stdTx, decodedTx)
-}
-
 func TestTestSuite(t *testing.T) {
 	suite.Run(t, new(TestSuite))
 }

x/auth/ante/sigverify.go

@@ -265,18 +265,11 @@ func (svd SigVerificationDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simul
 		}
 
 		// Check account sequence number.
-		// When using Amino StdSignatures, we actually don't have the Sequence in
-		// the SignatureV2 struct (it's only in the SignDoc). In this case, we
-		// cannot check sequence directly, and must do it via signature
-		// verification (in the VerifySignature call below).
-		onlyAminoSigners := OnlyLegacyAminoSigners(sig.Data)
-		if !onlyAminoSigners {
-			if sig.Sequence != acc.GetSequence() {
-				return ctx, sdkerrors.Wrapf(
-					sdkerrors.ErrWrongSequence,
-					"account sequence mismatch, expected %d, got %d", acc.GetSequence(), sig.Sequence,
-				)
-			}
+		if sig.Sequence != acc.GetSequence() {
+			return ctx, sdkerrors.Wrapf(
+				sdkerrors.ErrWrongSequence,
+				"account sequence mismatch, expected %d, got %d", acc.GetSequence(), sig.Sequence,
+			)
 		}
 
 		// retrieve signer data
@@ -296,7 +289,7 @@ func (svd SigVerificationDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simul
 			err := authsigning.VerifySignature(pubKey, signerData, sig.Data, svd.signModeHandler, tx)
 			if err != nil {
 				var errMsg string
-				if onlyAminoSigners {
+				if OnlyLegacyAminoSigners(sig.Data) {
 					// If all signers are using SIGN_MODE_LEGACY_AMINO, we rely on VerifySignature to check account sequence number,
 					// and therefore communicate sequence number as a potential cause of error.
 					errMsg = fmt.Sprintf("signature verification failed; please verify account number (%d), sequence (%d) and chain-id (%s)", accNum, acc.GetSequence(), chainID)