Merge #10942: Eliminate fee overpaying edge case when subtracting fee from recipients

49d903e Eliminate fee overpaying edge case when subtracting fee from recipients (Alex Morcos)

Pull request description:

  I'm not sure if this is the cause of the issue in #10034 , but this was a known edge case.  I just didn't realize how simple the fix is.

  Could use a couple more eyes to make sure nothing silly can go wrong here, but if we all agree it's this simple, we can add this as another 0.15 bug fix.

Tree-SHA512: db1dd1e83363a3c231267b626d3a388893ee70ba1972056fe2c339c5c9e4fbfd30f7fe837c30cc7be884d454797fd4c619b9d631a8d5eeb55cdb07402a83acb3
This commit is contained in:
Wladimir J. van der Laan 2017-08-03 12:26:09 +02:00
commit 2e857bb619
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@ -2789,10 +2789,6 @@ bool CWallet::CreateTransaction(const std::vector<CRecipient>& vecSend, CWalletT
// selected to meet nFeeNeeded result in a transaction that
// requires less fee than the prior iteration.
// TODO: The case where nSubtractFeeFromAmount > 0 remains
// to be addressed because it requires returning the fee to
// the payees and not the change output.
// If we have no change and a big enough excess fee, then
// try to construct transaction again only without picking
// new inputs. We now know we only need the smaller fee
@ -2819,6 +2815,8 @@ bool CWallet::CreateTransaction(const std::vector<CRecipient>& vecSend, CWalletT
else if (!pick_new_inputs) {
// This shouldn't happen, we should have had enough excess
// fee to pay for the new output and still meet nFeeNeeded
// Or we should have just subtracted fee from recipients and
// nFeeNeeded should not have changed
strFailReason = _("Transaction fee and change calculation failed");
return false;
}
@ -2835,6 +2833,12 @@ bool CWallet::CreateTransaction(const std::vector<CRecipient>& vecSend, CWalletT
}
}
// If subtracting fee from recipients, we now know what fee we
// need to subtract, we have no reason to reselect inputs
if (nSubtractFeeFromAmount > 0) {
pick_new_inputs = false;
}
// Include more fee and try again.
nFeeRet = nFeeNeeded;
continue;