Error Parsing Price for ManageSellOffer Operation

[qiwu7]

What version are you using?

5b5b4d6

What did you do?

use the following to retrieve envelope xdr

curl --location --request GET 'https://horizon-testnet.stellar.org/ledgers/142220/transactions' | jq '._embedded.records[1].envelope_xdr'

func main() {
	envelopeXDR := "AAAAAgAAAABDEP4VQWm3jomKahN5UCW4Bmxfym0cgn12vT4ThV81SgAAAGQAAiuJAAAAAgAAAAAAAAAAAAAAAQAAAAEAAAAAQxD+FUFpt46JimoTeVAluAZsX8ptHIJ9dr0+E4VfNUoAAAADAAAAAVNFQwAAAAAA4oSfAJtLwUw3su8iSHJB8refwQ45OL55+YxCq7vFHJEAAAAAAAAAADuaygAAAAABO5rKAAAAAAAAAAAAAAAAAAAAAAGFXzVKAAAAQLSJWk7CPp1N29pETu9uKYDJqqsHoH4LtsJV9aL6/nI5UNzcRGe0L4C0x47xMacezObrIw4N1Y6tbQ3LPla/sg4="
	genericTx, err := txnbuild.TransactionFromXDR(envelopeXDR)
	if err != nil {
		fmt.Println("error building generic transaction from envelope xdr")
	}
	// Unpacks the GenericTransaction instance into a txnbuild.Transaction
	tx, ok := genericTx.Transaction()
	if !ok {
		fmt.Println("error unpacking generic tx")
	}

	for _, op := range tx.Operations() {
		xdrOp, err := op.BuildXDR()
		if err != nil {
			fmt.Printf("error building xdrOp from txnbuild.Operation: %v\n", err)
		} else {
			fmt.Printf("successfully building xdrOp from txnbuild.Operation: %v\n", xdrOp)
		}
	}
}

then saw the following error

error building xdrOp from txnbuild.Operation: failed to parse 'Price': Couldn't find approximation

What did you expect to see?

I expect to build the xdr.Operation from the txnbuild.Operation successfully

What did you see instead?

But I saw an error while building it

error building xdrOp from txnbuild.Operation: failed to parse 'Price': Couldn't find approximation

Possible location that causes the failure

go/txnbuild/manage_offer.go

Lines 102 to 105 in 8c55e6b

	xdrPrice, err := price.Parse(mo.Price)
	if err != nil {
	return xdr.Operation{}, errors.Wrap(err, "failed to parse 'Price'")
	}

[ire-and-curses]

https://laboratory.stellar.org/#xdr-viewer?input=AAAAAgAAAABDEP4VQWm3jomKahN5UCW4Bmxfym0cgn12vT4ThV81SgAAAGQAAiuJAAAAAgAAAAAAAAAAAAAAAQAAAAEAAAAAQxD%2BFUFpt46JimoTeVAluAZsX8ptHIJ9dr0%2BE4VfNUoAAAADAAAAAVNFQwAAAAAA4oSfAJtLwUw3su8iSHJB8refwQ45OL55%2BYxCq7vFHJEAAAAAAAAAADuaygAAAAABO5rKAAAAAAAAAAAAAAAAAAAAAAGFXzVKAAAAQLSJWk7CPp1N29pETu9uKYDJqqsHoH4LtsJV9aL6%2FnI5UNzcRGe0L4C0x47xMacezObrIw4N1Y6tbQ3LPla%2Fsg4%3D&type=TransactionEnvelope&network=test

It seems to be a rounding problem in price.

Numerator: 1
Denominator: 1000000000
Result of price.StringFromFloat64(float64(result.Price.N) / float64(result.Price.D)): 0.0000000

//StringFromFloat64 will format a float64 to decimal representation with 7 digits after the decimal point
func StringFromFloat64(v float64) string {
	return strconv.FormatFloat(v, 'f', 7, 64)
}

[ire-and-curses]

Underlying issues that also need fixing: #2514, #2515

[bartekn]

Yes, looks like #2514 should fix this one. The code in

go/txnbuild/manage_offer.go

Lines 126 to 150 in 5b5b4d6

	func (mo *ManageSellOffer) FromXDR(xdrOp xdr.Operation) error {
	result, ok := xdrOp.Body.GetManageSellOfferOp()
	if !ok {
	return errors.New("error parsing manage_sell_offer operation from xdr")
	}
	mo.SourceAccount = accountFromXDR(xdrOp.SourceAccount)
	mo.OfferID = int64(result.OfferId)
	mo.Amount = amount.String(result.Amount)
	if result.Price != (xdr.Price{}) {
	mo.Price = price.StringFromFloat64(float64(result.Price.N) / float64(result.Price.D))
	}
	buyingAsset, err := assetFromXDR(result.Buying)
	if err != nil {
	return errors.Wrap(err, "error parsing buying_asset in manage_sell_offer operation")
	}
	mo.Buying = buyingAsset
	sellingAsset, err := assetFromXDR(result.Selling)
	if err != nil {
	return errors.Wrap(err, "error parsing selling_asset in manage_sell_offer operation")
	}
	mo.Selling = sellingAsset
	return nil
	}

tries to find a string/decimal representation of the price because manage offer builder accepts strings only. When #2514 is done we can simply pass N and D.

[qiwu7]

do we have an eta for this issue? Appreciated 🎉