imp(erc20): align allowance adjustment errors with erc20 contracts (e…

…vmos#2075)

* align allowance adjustment errors with erc20

* add changelog entry

CHANGELOG.md

@@ -108,6 +108,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 - (stride-outpost) [#2069](https://github.com/evmos/evmos/pull/2069) Refactor `osmosis` and `stride` testing.
 - (erc20) [#2073](https://github.com/evmos/evmos/pull/2073) Align metadata query errors with ERC20 contracts.
 - (werc20) [#2074](https://github.com/evmos/evmos/pull/2074) Add `werc20` EVM Extension acceptance tests with `WEVMOS` contract.
+- (erc20) [#2075](https://github.com/evmos/evmos/pull/2075) Align allowance adjustment errors with ERC20 contracts.
 
 ### Bug Fixes
 

precompiles/erc20/approve.go

@@ -189,7 +189,7 @@ func (p Precompile) DecreaseAllowance(
 		err = fmt.Errorf(ErrNoAllowanceForToken, p.tokenPair.Denom)
 	case subtractedValue != nil && subtractedValue.Cmp(allowance) > 0:
 		// case 6. subtractedValue positive and subtractedValue higher than allowance -> return error
-		err = fmt.Errorf(ErrSubtractMoreThanAllowance, p.tokenPair.Denom, subtractedValue, allowance)
+		err = ConvertErrToERC20Error(fmt.Errorf(ErrSubtractMoreThanAllowance, p.tokenPair.Denom, subtractedValue, allowance))
 	}
 
 	if err != nil {
@@ -247,9 +247,9 @@ func (p Precompile) removeSpendLimitOrDeleteAuthorization(ctx sdk.Context, grant
 	newSpendLimit, hasNeg := sendAuthz.SpendLimit.SafeSub(denomCoins)
 	// NOTE: safety check only, this should never happen since we only subtract what was found in the slice.
 	if hasNeg {
-		return fmt.Errorf(ErrSubtractMoreThanAllowance,
+		return ConvertErrToERC20Error(fmt.Errorf(ErrSubtractMoreThanAllowance,
 			p.tokenPair.Denom, denomCoins, sendAuthz.SpendLimit,
-		)
+		))
 	}
 
 	if newSpendLimit.IsZero() {
@@ -276,7 +276,7 @@ func (p Precompile) increaseAllowance(
 	sdkAddedValue := sdk.NewIntFromBigInt(addedValue)
 	amount, overflow := cmn.SafeAdd(allowance, sdkAddedValue)
 	if overflow {
-		return nil, errors.New(cmn.ErrIntegerOverflow)
+		return nil, ConvertErrToERC20Error(errors.New(cmn.ErrIntegerOverflow))
 	}
 
 	if err := p.updateAuthorization(ctx, grantee, granter, amount, sendAuthz, expiration); err != nil {
@@ -306,7 +306,7 @@ func (p Precompile) decreaseAllowance(
 	amount = new(big.Int).Sub(allowance.Amount.BigInt(), subtractedValue)
 	// NOTE: Safety check only since this is checked in the DecreaseAllowance method already.
 	if amount.Sign() < 0 {
-		return nil, fmt.Errorf(ErrSubtractMoreThanAllowance, p.tokenPair.Denom, subtractedValue, allowance.Amount)
+		return nil, ConvertErrToERC20Error(fmt.Errorf(ErrSubtractMoreThanAllowance, p.tokenPair.Denom, subtractedValue, allowance.Amount))
 	}
 
 	if err := p.updateAuthorization(ctx, grantee, granter, amount, sendAuthz, expiration); err != nil {

precompiles/erc20/approve_test.go

@@ -1,6 +1,7 @@
 package erc20_test
 
 import (
+	"errors"
 	"fmt"
 	"math/big"
 
@@ -376,7 +377,7 @@ func (s *PrecompileTestSuite) TestIncreaseAllowance() {
 					s.keyring.GetAddr(1), big.NewInt(amount),
 				}
 			},
-			errContains: cmn.ErrIntegerOverflow,
+			errContains: erc20.ConvertErrToERC20Error(errors.New(cmn.ErrIntegerOverflow)).Error(),
 			postCheck: func() {
 				s.requireSendAuthz(
 					s.keyring.GetAccAddr(1),
@@ -664,7 +665,7 @@ func (s *PrecompileTestSuite) TestDecreaseAllowance() {
 					s.keyring.GetAddr(1), big.NewInt(amount + 1),
 				}
 			},
-			errContains: "subtracted value cannot be greater than existing allowance",
+			errContains: erc20.ConvertErrToERC20Error(errors.New("subtracted value cannot be greater than existing allowance")).Error(),
 		},
 		{
 			name: "fail - decrease allowance with existing authorization in different denomination",
@@ -703,7 +704,7 @@ func (s *PrecompileTestSuite) TestDecreaseAllowance() {
 					s.keyring.GetAddr(1), big.NewInt(decreaseAmount),
 				}
 			},
-			errContains: "subtracted value cannot be greater than existing allowance",
+			errContains: erc20.ConvertErrToERC20Error(errors.New("subtracted value cannot be greater than existing allowance")).Error(),
 			postCheck: func() {
 				// NOTE: Here we check that the authorization was not adjusted
 				s.requireSendAuthz(

precompiles/erc20/errors.go

@@ -11,6 +11,7 @@ import (
 	"github.com/ethereum/go-ethereum/accounts/abi"
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/crypto"
+	cmn "github.com/evmos/evmos/v15/precompiles/common"
 	evmtypes "github.com/evmos/evmos/v15/x/evm/types"
 )
 
@@ -32,11 +33,9 @@ var (
 	ErrNegativeAmount           = errors.New("cannot approve negative values")
 	ErrNoIBCVoucherDenom        = errors.New("denom is not an IBC voucher")
 
-	// ErrInsufficientAllowance is returned by ERC20 smart contracts in case
-	// no authorization is found or the granted amount is not sufficient.
-	ErrInsufficientAllowance = errors.New("ERC20: insufficient allowance")
-	// ErrTransferAmountExceedsBalance is returned by ERC20 smart contracts in
-	// case a transfer is attempted, that sends more than the sender's balance.
+	// ERC20 errors
+	ErrDecreasedAllowanceBelowZero  = errors.New("ERC20: decreased allowance below zero")
+	ErrInsufficientAllowance        = errors.New("ERC20: insufficient allowance")
 	ErrTransferAmountExceedsBalance = errors.New("ERC20: transfer amount exceeds balance")
 )
 
@@ -63,20 +62,24 @@ func BuildExecRevertedErr(reason string) (error, error) {
 	return evmtypes.NewExecErrorWithReason(reasonBytes), nil
 }
 
-// convertErrToERC20Error is a helper function which maps errors raised by the Cosmos SDK stack
+// ConvertErrToERC20Error is a helper function which maps errors raised by the Cosmos SDK stack
 // to the corresponding errors which are raised by an ERC20 contract.
 //
 // TODO: Create the full RevertError types instead of just the standard error type.
 //
 // TODO: Return ERC-6093 compliant errors.
-func convertErrToERC20Error(err error) error {
+func ConvertErrToERC20Error(err error) error {
 	switch {
 	case strings.Contains(err.Error(), "spendable balance"):
 		return ErrTransferAmountExceedsBalance
 	case strings.Contains(err.Error(), "requested amount is more than spend limit"):
 		return ErrInsufficientAllowance
 	case strings.Contains(err.Error(), authz.ErrNoAuthorizationFound.Error()):
 		return ErrInsufficientAllowance
+	case strings.Contains(err.Error(), "subtracted value cannot be greater than existing allowance"):
+		return ErrDecreasedAllowanceBelowZero
+	case strings.Contains(err.Error(), cmn.ErrIntegerOverflow):
+		return vm.ErrExecutionReverted
 	case errors.Is(err, ErrNoIBCVoucherDenom) ||
 		errors.Is(err, ErrDenomTraceNotFound) ||
 		strings.Contains(err.Error(), "invalid base denomination") ||

precompiles/erc20/query.go

@@ -59,7 +59,7 @@ func (p Precompile) Name(
 
 	baseDenom, err := p.getBaseDenomFromIBCVoucher(ctx, p.tokenPair.Denom)
 	if err != nil {
-		return nil, convertErrToERC20Error(err)
+		return nil, ConvertErrToERC20Error(err)
 	}
 
 	name := strings.ToUpper(string(baseDenom[1])) + baseDenom[2:]
@@ -83,7 +83,7 @@ func (p Precompile) Symbol(
 
 	baseDenom, err := p.getBaseDenomFromIBCVoucher(ctx, p.tokenPair.Denom)
 	if err != nil {
-		return nil, convertErrToERC20Error(err)
+		return nil, ConvertErrToERC20Error(err)
 	}
 
 	symbol := strings.ToUpper(baseDenom[1:])
@@ -104,7 +104,7 @@ func (p Precompile) Decimals(
 	if !found {
 		denomTrace, err := GetDenomTrace(p.transferKeeper, ctx, p.tokenPair.Denom)
 		if err != nil {
-			return nil, convertErrToERC20Error(err)
+			return nil, ConvertErrToERC20Error(err)
 		}
 
 		// we assume the decimal from the first character of the denomination
@@ -114,7 +114,7 @@ func (p Precompile) Decimals(
 		case "a": // atto (a) -> 18 decimals
 			return method.Outputs.Pack(uint8(18))
 		}
-		return nil, convertErrToERC20Error(fmt.Errorf(
+		return nil, ConvertErrToERC20Error(fmt.Errorf(
 			"invalid base denomination; should be either micro ('u[...]') or atto ('a[...]'); got: %q",
 			denomTrace.BaseDenom,
 		))
@@ -133,14 +133,14 @@ func (p Precompile) Decimals(
 	}
 
 	if !displayFound {
-		return nil, convertErrToERC20Error(fmt.Errorf(
+		return nil, ConvertErrToERC20Error(fmt.Errorf(
 			"display denomination not found for denom: %q",
 			p.tokenPair.Denom,
 		))
 	}
 
 	if decimals > math.MaxUint8 {
-		return nil, convertErrToERC20Error(fmt.Errorf(
+		return nil, ConvertErrToERC20Error(fmt.Errorf(
 			"uint8 overflow: invalid decimals: %d",
 			decimals,
 		))

precompiles/erc20/tx.go

@@ -90,7 +90,7 @@ func (p Precompile) transfer(
 	}
 
 	if err != nil {
-		err = convertErrToERC20Error(err)
+		err = ConvertErrToERC20Error(err)
 		// This should return an error to avoid the contract from being executed and an event being emitted
 		return nil, err
 	}