[bug]: failed funding broadcast doesn't remove pending channels and unlock UTXOs

[Roasbeef]

Background

If we fail a broadcast, we don't do anything, and the channel just sits there. This still occupies the locked UTXOs, and also the pending channel entry in the database:

lnd/funding/manager.go

Lines 2448 to 2463 in 03b26bb

	err = f.cfg.PublishTransaction(fundingTx, label)
	if err != nil {
	log.Errorf("Unable to broadcast funding tx %x for "+
	"ChannelPoint(%v): %v", fundingTxBuf.Bytes(),
	completeChan.FundingOutpoint, err)
	// We failed to broadcast the funding transaction, but
	// watch the channel regardless, in case the
	// transaction made it to the network. We will retry
	// broadcast at startup.
	//
	// TODO(halseth): retry more often? Handle with CPFP?
	// Just delete from the DB?
	}
	}

Steps to reproduce

Double spend a UTXO in a funding transaction.

Expected behaviour

UTXO unlocked, and pending channel cleared.

Actual behaviour

UTXOs still locked, channel shows up in lncli pendingchannels.

[yyforyongyu]

related to this old PR?

• Close pending channel when unexpected error is returned from PublishTransaction #5158

[Roasbeef]

@yyforyongyu yep, I think let's re-open that PR and also its follow up (#6400)

[theborakompanioni]

This recently happened with a peer of mine, after abandonchannel (abandonchannel is a dangerous command and can lead to loss of funds if used incorrectly - ask in our slack channel if unsure) and a node restart, the channel is gone (as expected), but the UTXOs used for the funding TX are still not credited.

Maybe noteworty: The funding TX contained 4 UTXOs. 2 fully confirmed, one with 0 conf and one that got purged from (probably most) mempools.

Similar to #7502 I suppose. What is the suggested procedure here. Would lncli sendcoins --sweepall (as suggested in the linked ticket) pick up the UTXOs and lead to the desired outcome?

[guggero]

@theborakompanioni try starting lnd with the reset-wallet-transactions=true setting (make sure to let it fully sync as a restart won't resume it and leave the wallet in an incomplete state, check the log for progress).

[theborakompanioni]

@theborakompanioni try starting lnd with the reset-wallet-transactions=true setting (make sure to let it fully sync as a restart won't resume it and leave the wallet in an incomplete state, check the log for progress).

Got a reply from the peer. Unfortunately, that did not do the trick. Change Output from the "unbroadcasted" funding TX is still present in listunspent - UTXOs used as inputs for the funding TX not credited 😬

It feels, according to the docs, it should have worked, right? How can it be that the Change Output is still present in listunspent after --reset-wallet-transactions?

Any other things to try? Feeling a bit bad that I cannot help him.. was really confident that this would work.

[guggero]

Are they using Neutrino? Can you paste the output of listunspent please?

[theborakompanioni]

Are they using Neutrino? Can you paste the output of listunspent please?

I am sorry, I think I am not entitled to publish such private information of another noderunner here.
Wrote you a DM and connected you with the original peer. Thanks @guggero, highly appreciate your help 🙏
Hopefully some useful insights will come to light that will help you and the project as well.

Edit: This case is now resolved - chantools with doublespendinputs did the trick. 🙌