refactor: Change SignerData.SignerIndex to PubKey (#10692)

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## Description

Closes: #10691 

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---

### Author Checklist

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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

@@ -114,6 +114,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * [\#10348](https://github.com/cosmos/cosmos-sdk/pull/10348) StdSignBytes takes a new argument of type `*tx.Tip` for signing over tips using LEGACY_AMINO_JSON.
 * [\#10208](https://github.com/cosmos/cosmos-sdk/pull/10208) The `x/auth/signing.Tx` interface now also includes a new `GetTip() *tx.Tip` method for verifying tipped transactions. The `x/auth/types` expected BankKeeper interface now expects the `SendCoins` method too.
 * [\#10612](https://github.com/cosmos/cosmos-sdk/pull/10612) `baseapp.NewBaseApp` constructor function doesn't take the `sdk.TxDecoder` anymore. This logic has been moved into the TxDecoderMiddleware.
+* [\#10692](https://github.com/cosmos/cosmos-sdk/pull/10612) `SignerData` takes 2 new fields, `Address` and `PubKey`, which need to get populated when using SIGN_MODE_DIRECT_AUX.
 
 ### Client Breaking Changes
 

client/tx/tx.go

@@ -247,24 +247,11 @@ func Sign(txf Factory, name string, txBuilder client.TxBuilder, overwriteSig boo
 		return err
 	}
 
-	pubkeys, err := txBuilder.GetTx().GetPubKeys()
-	if err != nil {
-		return err
-	}
-
-	signerIndex := 0
-	for i, p := range pubkeys {
-		if p.Equals(pubKey) {
-			signerIndex = i
-			break
-		}
-	}
-
 	signerData := authsigning.SignerData{
 		ChainID:       txf.chainID,
 		AccountNumber: txf.accountNumber,
 		Sequence:      txf.sequence,
-		SignerIndex:   signerIndex,
+		PubKey:        pubKey,
 		Address:       sdk.AccAddress(pubKey.Address()).String(),
 	}
 

server/rosetta/converter.go

@@ -720,7 +720,7 @@ func (c converter) SigningComponents(tx authsigning.Tx, metadata *ConstructionMe
 			ChainID:       metadata.ChainID,
 			AccountNumber: metadata.SignersData[i].AccountNumber,
 			Sequence:      metadata.SignersData[i].Sequence,
-			SignerIndex:   i,
+			PubKey:        pubKey,
 		}
 
 		// get signature bytes

simapp/helpers/test_helpers.go

@@ -61,7 +61,7 @@ func GenTx(gen client.TxConfig, msgs []sdk.Msg, feeAmt sdk.Coins, gas uint64, ch
 			ChainID:       chainID,
 			AccountNumber: accNums[i],
 			Sequence:      accSeqs[i],
-			SignerIndex:   i,
+			PubKey:        p.PubKey(),
 		}
 		signBytes, err := gen.SignModeHandler().GetSignBytes(signMode, signerData, tx.GetTx())
 		if err != nil {

x/auth/client/cli/tx_multisign.go

@@ -127,13 +127,13 @@ func makeMultiSignCmd() func(cmd *cobra.Command, args []string) (err error) {
 				return fmt.Errorf("set the chain id with either the --chain-id flag or config file")
 			}
 
-			for j, sig := range sigs {
+			for _, sig := range sigs {
 				signingData := signing.SignerData{
 					Address:       sdk.AccAddress(sig.PubKey.Address()).String(),
 					ChainID:       txFactory.ChainID(),
 					AccountNumber: txFactory.AccountNumber(),
 					Sequence:      txFactory.Sequence(),
-					SignerIndex:   j,
+					PubKey:        sig.PubKey,
 				}
 
 				err = signing.VerifySignature(sig.PubKey, signingData, sig.Data, txCfg.SignModeHandler(), txBuilder.GetTx())
@@ -328,7 +328,7 @@ func makeBatchMultisignCmd() func(cmd *cobra.Command, args []string) error {
 				ChainID:       txFactory.ChainID(),
 				AccountNumber: txFactory.AccountNumber(),
 				Sequence:      txFactory.Sequence(),
-				SignerIndex:   i,
+				PubKey:        pubKey,
 			}
 
 			for _, sig := range signatureBatch {

x/auth/client/cli/validate_sigs.go

@@ -110,7 +110,7 @@ func printAndValidateSigs(
 				ChainID:       chainID,
 				AccountNumber: accNum,
 				Sequence:      accSeq,
-				SignerIndex:   i,
+				PubKey:        pubKey,
 			}
 			err = authsigning.VerifySignature(pubKey, signingData, sig.Data, signModeHandler, sigTx)
 			if err != nil {

x/auth/middleware/feegrant_test.go

@@ -216,7 +216,7 @@ func genTxWithFeeGranter(gen client.TxConfig, msgs []sdk.Msg, feeAmt sdk.Coins,
 			ChainID:       chainID,
 			AccountNumber: accNums[i],
 			Sequence:      accSeqs[i],
-			SignerIndex:   i,
+			PubKey:        p.PubKey(),
 		}
 		signBytes, err := gen.SignModeHandler().GetSignBytes(signMode, signerData, tx.GetTx())
 		if err != nil {

x/auth/middleware/sigverify.go

@@ -487,7 +487,7 @@ func (svd sigVerificationTxHandler) sigVerify(ctx context.Context, req tx.Reques
 			ChainID:       chainID,
 			AccountNumber: accNum,
 			Sequence:      acc.GetSequence(),
-			SignerIndex:   i,
+			PubKey:        pubKey,
 		}
 
 		if !simulate {

x/auth/middleware/testutil_test.go

@@ -151,7 +151,7 @@ func (s *MWTestSuite) createTestTx(txBuilder client.TxBuilder, privs []cryptotyp
 			ChainID:       chainID,
 			AccountNumber: accNums[i],
 			Sequence:      accSeqs[i],
-			SignerIndex:   i,
+			PubKey:        priv.PubKey(),
 		}
 		sigV2, err := tx.SignWithPrivKey(
 			s.clientCtx.TxConfig.SignModeHandler().DefaultMode(), signerData,

x/auth/middleware/tips_test.go

@@ -191,7 +191,7 @@ func (s *MWTestSuite) mkFeePayerTxBuilder(
 		ChainID:       chainID,
 		AccountNumber: accNum,
 		Sequence:      accSeq,
-		SignerIndex:   1,
+		PubKey:        feePayerPriv.PubKey(),
 	}
 	feePayerSigV2, err = clienttx.SignWithPrivKey(
 		signMode, signerData,

x/auth/migrations/legacytx/amino_signing_test.go

@@ -50,7 +50,7 @@ func TestLegacyAminoJSONHandler_GetSignBytes(t *testing.T) {
 		ChainID:       chainId,
 		AccountNumber: accNum,
 		Sequence:      seqNum,
-		SignerIndex:   0,
+		PubKey:        priv1.PubKey(),
 	}
 	signBz, err := handler.GetSignBytes(signingtypes.SignMode_SIGN_MODE_LEGACY_AMINO_JSON, signingData, tx)
 	require.NoError(t, err)

x/auth/signing/handler_map_test.go

@@ -64,7 +64,7 @@ func TestHandlerMap_GetSignBytes(t *testing.T) {
 		ChainID:       chainId,
 		AccountNumber: accNum,
 		Sequence:      seqNum,
-		SignerIndex:   0,
+		PubKey:        priv1.PubKey(),
 	}
 	signBz, err := handler.GetSignBytes(signingtypes.SignMode_SIGN_MODE_LEGACY_AMINO_JSON, signingData, tx)
 	require.NoError(t, err)

x/auth/signing/sign_mode_handler.go

@@ -1,6 +1,7 @@
 package signing
 
 import (
+	cryptotypes "github.com/cosmos/cosmos-sdk/crypto/types"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/types/tx/signing"
 )
@@ -24,20 +25,29 @@ type SignModeHandler interface {
 // isn't included in the transaction body itself
 type SignerData struct {
 	// The address of the signer.
+	//
+	// In case of multisigs, this should be the multisig's address.
 	Address string
 
 	// ChainID is the chain that this transaction is targeted
 	ChainID string
 
-	// AccountNumber is the account number of the signer
+	// AccountNumber is the account number of the signer.
+	//
+	// In case of multisigs, this should be the multisig account number.
 	AccountNumber uint64
 
 	// Sequence is the account sequence number of the signer that is used
 	// for replay protection. This field is only useful for Legacy Amino signing,
 	// since in SIGN_MODE_DIRECT the account sequence is already in the signer
 	// info.
+	//
+	// In case of multisigs, this should be the multisig account number.
 	Sequence uint64
 
-	// SignerIndex index of signer in the signer_infos array.
-	SignerIndex int
+	// PubKey is the public key of the signer.
+	//
+	// In case of multisigs, this should be the pubkey of the member of the
+	// multisig that is signing the current sign doc.
+	PubKey cryptotypes.PubKey
 }

x/auth/signing/verify_test.go

@@ -53,7 +53,7 @@ func TestVerifySignature(t *testing.T) {
 		ChainID:       chainId,
 		AccountNumber: acc.GetAccountNumber(),
 		Sequence:      acc.GetSequence(),
-		SignerIndex:   0,
+		PubKey:        pubKey,
 	}
 	signBytes := legacytx.StdSignBytes(signerData.ChainID, signerData.AccountNumber, signerData.Sequence, 10, fee, msgs, memo, nil)
 	signature, err := priv.Sign(signBytes)

x/auth/testutil/suite.go

@@ -132,7 +132,7 @@ func (s *TxConfigTestSuite) TestTxBuilderSetSignatures() {
 		ChainID:       "test",
 		AccountNumber: 1,
 		Sequence:      seq1,
-		SignerIndex:   0,
+		PubKey:        pubkey,
 	}
 	signBytes, err := signModeHandler.GetSignBytes(signModeHandler.DefaultMode(), signerData, sigTx)
 	s.Require().NoError(err)
@@ -144,7 +144,7 @@ func (s *TxConfigTestSuite) TestTxBuilderSetSignatures() {
 		ChainID:       "test",
 		AccountNumber: 3,
 		Sequence:      mseq,
-		SignerIndex:   0,
+		PubKey:        multisigPk,
 	}
 	mSignBytes, err := signModeHandler.GetSignBytes(signModeHandler.DefaultMode(), signerData, sigTx)
 	s.Require().NoError(err)

x/auth/tx/aux_test.go

@@ -130,7 +130,13 @@ func TestBuilderWithAux(t *testing.T) {
 	})
 	signBz, err = encCfg.TxConfig.SignModeHandler().GetSignBytes(
 		signing.SignMode_SIGN_MODE_DIRECT,
-		authsigning.SignerData{Address: feepayerAddr.String(), ChainID: chainID, AccountNumber: 11, Sequence: 15, SignerIndex: 1},
+		authsigning.SignerData{
+			Address:       feepayerAddr.String(),
+			ChainID:       chainID,
+			AccountNumber: 11,
+			Sequence:      15,
+			PubKey:        feepayerPk,
+		},
 		w.GetTx(),
 	)
 	require.NoError(t, err)

x/auth/tx/direct_aux.go

@@ -3,6 +3,7 @@ package tx
 import (
 	"fmt"
 
+	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	types "github.com/cosmos/cosmos-sdk/types/tx"
@@ -39,9 +40,9 @@ func (signModeDirectAuxHandler) GetSignBytes(
 		return nil, fmt.Errorf("can only handle a protobuf Tx, got %T", tx)
 	}
 
-	signerInfo := protoTx.tx.AuthInfo.SignerInfos[data.SignerIndex]
-	if signerInfo == nil || signerInfo.PublicKey == nil {
-		return nil, sdkerrors.ErrInvalidRequest.Wrapf("got empty pubkey for signer #%d in %s handler", data.SignerIndex, signingtypes.SignMode_SIGN_MODE_DIRECT_AUX)
+	pkAny, err := codectypes.NewAnyWithValue(data.PubKey)
+	if err != nil {
+		return nil, err
 	}
 
 	addr := data.Address
@@ -61,9 +62,9 @@ func (signModeDirectAuxHandler) GetSignBytes(
 		BodyBytes:     protoTx.getBodyBytes(),
 		ChainId:       data.ChainID,
 		AccountNumber: data.AccountNumber,
-		Sequence:      signerInfo.Sequence,
+		Sequence:      data.Sequence,
 		Tip:           protoTx.tx.AuthInfo.Tip,
-		PublicKey:     signerInfo.PublicKey,
+		PublicKey:     pkAny,
 	}
 
 	return signDocDirectAux.Marshal()

x/auth/tx/direct_aux_test.go

@@ -66,13 +66,15 @@ func TestDirectAuxHandler(t *testing.T) {
 		Address:       addr.String(),
 		ChainID:       chainID,
 		AccountNumber: accNum,
-		SignerIndex:   0,
+		Sequence:      accSeq,
+		PubKey:        pubkey,
 	}
 	feePayerSigningData := signing.SignerData{
 		Address:       feePayerAddr.String(),
 		ChainID:       chainID,
 		AccountNumber: accNum,
-		SignerIndex:   1,
+		Sequence:      accSeq,
+		PubKey:        feePayerPubKey,
 	}
 
 	modeHandler := signModeDirectAuxHandler{}

x/auth/tx/direct_test.go

@@ -72,7 +72,7 @@ func TestDirectModeHandler(t *testing.T) {
 		Address:       addr.String(),
 		ChainID:       "test-chain",
 		AccountNumber: 1,
-		SignerIndex:   0,
+		PubKey:        pubkey,
 	}
 
 	signBytes, err := modeHandler.GetSignBytes(signingtypes.SignMode_SIGN_MODE_DIRECT, signingData, txBuilder.GetTx())

x/auth/tx/legacy_amino_json_test.go

@@ -15,8 +15,8 @@ import (
 )
 
 var (
-	_, _, addr1 = testdata.KeyTestPubAddr()
-	_, _, addr2 = testdata.KeyTestPubAddr()
+	_, pubkey1, addr1 = testdata.KeyTestPubAddr()
+	_, _, addr2       = testdata.KeyTestPubAddr()
 
 	coins   = sdk.Coins{sdk.NewInt64Coin("foocoin", 10)}
 	gas     = uint64(10000)
@@ -112,7 +112,7 @@ func TestLegacyAminoJSONHandler_GetSignBytes(t *testing.T) {
 		ChainID:       chainId,
 		AccountNumber: accNum,
 		Sequence:      seqNum,
-		SignerIndex:   0,
+		PubKey:        pubkey1,
 	}
 
 	// expect error with wrong sign mode