bitcoin core send a -1 confirmations transaction...

[livte]

first , sorry my poor English and a newbie here :|

my bitcoin core server (v0.11.0 official from : https://bitcoin.org/zh_TW/download) send a transaction like this
(Linux SKIP 3.13.0-29-generic #53-Ubuntu SMP Wed Jun 4 21:00:20 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux)

Code:

bitcoin-cli gettransaction fbf40b5ee309576b052e482907b25d96b2c9c85b5947683b45e97d6d27395b63
{
    "amount" : -0.80392314,
    "fee" : -0.00010000,
    "confirmations" : -1,
    "txid" : "fbf40b5ee309576b052e482907b25d96b2c9c85b5947683b45e97d6d27395b63",
    "walletconflicts" : [
    ],
    "time" : 1444581926,
    "timereceived" : 1444581926,
    "details" : [
        {
            "account" : "",
            "address" : "1A9ANWVx9GaG29abAucMXgAsXL8ePxiUsA",
            "category" : "send",
            "amount" : -0.80392314,
            "vout" : 1,
            "fee" : -0.00010000
        }
    ],
    "hex" : SKIP
}

my question is "confirmations -1" will be very often? or just I unlucky?
and just skip it and re-send it?

and I get "confirmations -1" receive transaction too ...... so what can I do?

Code:

bitcoin-cli gettransaction 464103d3278f5e2cbb2afbf4280df6254a620de3b57a258d311c4f005b8a0bb1
{
    "amount" : 1.71121252,
    "confirmations" : -1,
    "txid" : "464103d3278f5e2cbb2afbf4280df6254a620de3b57a258d311c4f005b8a0bb1",
    "walletconflicts" : [
    ],
    "time" : 1444651482,
    "timereceived" : 1444651482,
    "details" : [
    ],
    "hex" : SKIP
}

and it's a bug from this? (has fixed)

https://bitcoin.org/en/alert/2015-10-12-upnp-vulnerability

[livte]

so I just skip it (receive transactions) or re-send it (send transactions) is okay when the transaction be -1 confirmation?

[achow101]

This is a result of the transaction malleability attack. Just wait.

[Hyena]

Many developers will shoot into their leg because of this -1  thing, mark my words.

if (conf != 0) send_the_money(); construct can no longer be used. Instead, developers should use if (conf > 0) send_the_money();

[livte]

we need show the transaction to customer when 0 confirm ... , so I don't know how to show when it be -1

and if I send a -1 transaction , can I just send again? , or wait a long time to check?

[fbueller]

-1 means there was a conflicting transaction.

Wait a long time. You see YOUR transaction as -1, but how do you know the malleated copy has not confirmed? Maybe check a few explorers for that address, to see if any still have transactions in the mempool, or if a payment confirmed with same value confirmed around the same time.

Malleabililty causes transactions to have different txids, so, if your wallet thinks it went out as aaba....., but it confirmed as d4d3... It will mark the first as -1, and deduct from your wallet anyway.

@livte - You are aware allowing 0 confirmation transactions to be spent is totally unsafe? If your product touches customer funds, you'll be inviting either (i) fraud, or (ii) customers wondering why their money isn't going through (iii) or it showing up twice....

Find me one place that says 0-conf is safe.

[livte]

Our service is 4+ confirm to success , but need show the transaction when 0 confirm for my customer

and I upgraded 0.11.1 and hope it work with less -1 confirm (send / receive) , thanx dev team

[onemorexmr]

-1 means there was a conflicting transaction.

Wait a long time. You see YOUR transaction as -1, but how do you know the malleated copy has not confirmed? Maybe check a few explorers for that address, to see if any still have transactions in the mempool, or if a payment confirmed with same value confirmed around the same time.

Malleabililty causes transactions to have different txids, so, if your wallet thinks it went out as aaba....., but it confirmed as d4d3... It will mark the first as -1, and deduct from your wallet anyway.

@livte - You are aware allowing 0 confirmation transactions to be spent is totally unsafe? If your product touches customer funds, you'll be inviting either (i) fraud, or (ii) customers wondering why their money isn't going through (iii) or it showing up twice....

Find me one place that says 0-conf is safe.

you can check if the outputs of your original transactions has been spent to the correct recipient.
if thats the case your transaction has been mallated and accepted by a miner...

hopefully this problem goes away fast (afaik as soon as all miners stop acception highS transactions)