fix: prevent panic in RedeemTokensForShares when too few tokens are redeemed

x/staking/keeper/msg_server.go

@@ -861,6 +861,11 @@ func (k msgServer) RedeemTokensForShares(goCtx context.Context, msg *types.MsgRe
 	}
 	tokens := validator.TokensFromShares(shares).TruncateInt()
 
+	// prevent redemption that returns a 0 amount
+	if tokens.IsZero() {
+		return nil, types.ErrTinyRedemptionAmount
+	}
+
 	// If this redemption is NOT from a liquid staking provider, decrement the total liquid staked
 	// If the redemption was from a liquid staking provider, the shares are still considered
 	// liquid, even in their non-tokenized form (since they are owned by a liquid staking provider)

x/staking/simulation/operations.go

@@ -923,8 +923,10 @@ func SimulateMsgRedeemTokensforShares(ak types.AccountKeeper, bk types.BankKeepe
 		}
 
 		// prevent redemption that returns a 0 amount
-		shareDenomSupply := bk.GetSupply(ctx, tokenizeShareRecord.GetShareTokenDenom())
-		shares := delegation.Shares.Mul(sdk.NewDecFromInt(redeemCoin.Amount)).QuoInt(shareDenomSupply.Amount)
+		shares := sdk.NewDecFromInt(redeemCoin.Amount)
+		if redeemCoin.Amount.Equal(delegation.Shares.TruncateInt()) {
+			shares = delegation.Shares
+		}
 
 		if validator.TokensFromShares(shares).TruncateInt().IsZero() {
 			return simtypes.NoOpMsg(types.ModuleName, types.TypeMsgRedeemTokensForShares, "zero tokens returned"), nil, nil

x/staking/types/errors.go

@@ -70,4 +70,5 @@ var (
 	ErrTokenizeSharesAlreadyDisabledForAccount  = sdkerrors.Register(ModuleName, 116, "tokenize shares is already disabled for this account")
 	ErrValidatorLiquidSharesUnderflow           = sdkerrors.Register(ModuleName, 117, "validator liquid shares underflow")
 	ErrTotalLiquidStakedUnderflow               = sdkerrors.Register(ModuleName, 118, "total liquid staked underflow")
+	ErrTinyRedemptionAmount                     = sdkerrors.Register(ModuleName, 119, "too few tokens to redeem (truncates to zero tokens)")
 )