Promote old transaction instead of reattaching them

Question

After waiting a while, my wallet did no longer allow to promote my transaction and forced me to reattach.

That forced me into reattaching the transaction, in the process I "doomed" three other non-zero transactions attached to mine. I waited over an hour with reattaching...

Why does my wallet not allow me to promote? Is there any reason - as long as a transaction can still confirm - to not promote them, even if they are already a few hours/days old? After all this doesn't "doom" transactions and requires far less POW.

Answer 1

When you select a transction in your wallet, the wallet will ask your connected node if it considers the transaction bundle still consistent. A transaction bundle can become inconsistent if one of its two approving transactions (which were chosen at the time when you initially attached your transaction) are double-spends (or reattachments) of already confirmed transactions, or if they themselves are inconsistent because one of their appoving transactions are double-spends or attachmetns. That means that your transaction (and everything attached to it) is already "doomed" and the only way for you (and the other transactions attached to it) to get your transaction confirmed is to reattach.

(I have seen reports on slack where people claim that their transaction cannot be promoted although there was no obvious reattached transaction found in its approved transactions (down to the point where they got confirmed). So far I think this has not been able to be reproduced (since those people reattachedd their transaction before someone could have a look at it), but it could as well be that there is a bug in either the wallet or the full node that may result in wrong decisions in rare cases (perhaps try changing node when it happens the next time?). So far this is only speculation, though.)