fix: Module sends with correct API

x/auction/keeper/auction.go

@@ -102,10 +102,7 @@
 
 	var proposerReward sdk.Coins
 	if params.ProposerFee.IsZero() {
-		// send the entire bid to the escrow account when no proposer fee is set
-		if err := k.bankKeeper.SendCoins(ctx, bidder, escrowAddress, sdk.NewCoins(bid)); err != nil {
-			return err
-		}
+		return k.SendBid(ctx, bidder, escrowAddress, sdk.NewCoins(bid))
 	} else {
 		rewardsAddress, err := k.rewardsAddressProvider.GetRewardsAddress(ctx)
 		if err != nil {
@@ -118,7 +115,7 @@
 		bid := sdk.NewDecCoinsFromCoins(bid)
 		proposerReward, _ = bid.MulDecTruncate(params.ProposerFee).TruncateDecimal()
 
-		if err := k.bankKeeper.SendCoins(ctx, bidder, rewardsAddress, proposerReward); err != nil {
+		if err := k.SendBid(ctx, bidder, rewardsAddress, proposerReward); err != nil {
 			return err
 		}
 
@@ -127,7 +124,7 @@
 		escrowTotal := bid.Sub(sdk.NewDecCoinsFromCoins(proposerReward...))
 		escrowReward, _ := escrowTotal.TruncateDecimal()
 
-		if err := k.bankKeeper.SendCoins(ctx, bidder, escrowAddress, escrowReward); err != nil {
+		if err := k.SendBid(ctx, bidder, escrowAddress, escrowReward); err != nil {
 			return err
 		}
 	}
@@ -206,6 +203,16 @@
 	return nil
 }
 
+// SendBid sends the bid from the bidder to the relevant address.
+func (k Keeper) SendBid(ctx sdk.Context, from, to sdk.AccAddress, bid sdk.Coins) error {
+	moduleAddress := k.accountKeeper.GetModuleAddress(types.ModuleName)
+	if moduleAddress.Equals(to) {
+		return k.bankKeeper.SendCoinsFromAccountToModule(ctx, from, types.ModuleName, bid)
+	}
+
+	return k.bankKeeper.SendCoins(ctx, from, to, bid)
+}
+
 // filterSigners removes any signers from the currentSigners map that are not in the txSigners map.
 func filterSigners(currentSigners, txSigners map[string]struct{}) {
 	for signer := range currentSigners {

x/auction/keeper/keeper.go

@@ -18,6 +18,7 @@ type Keeper struct {
 	cdc      codec.BinaryCodec
 	storeKey storetypes.StoreKey
 
+	accountKeeper          types.AccountKeeper
 	bankKeeper             types.BankKeeper
 	rewardsAddressProvider types.RewardsAddressProvider
 
@@ -73,6 +74,7 @@ func NewKeeperWithRewardsAddressProvider(
 	return Keeper{
 		cdc:                    cdc,
 		storeKey:               storeKey,
+		accountKeeper:          accountKeeper,
 		bankKeeper:             bankKeeper,
 		rewardsAddressProvider: rewardsAddressProvider,
 		authority:              authority,

x/auction/types/expected_keepers.go

@@ -16,6 +16,7 @@ type AccountKeeper interface {
 //
 //go:generate mockery --name BankKeeper --output ./mocks --outpkg mocks --case underscore
 type BankKeeper interface {
+	SendCoinsFromAccountToModule(ctx sdk.Context, senderAddr sdk.AccAddress, recipientModule string, amt sdk.Coins) error
 	SendCoins(ctx sdk.Context, fromAddr sdk.AccAddress, toAddr sdk.AccAddress, amt sdk.Coins) error
 	GetBalance(ctx sdk.Context, addr sdk.AccAddress, denom string) sdk.Coin
 }