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tapchannel: use defer to ensure lease unlocked if funding failure #1033

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merged 1 commit into from
Jul 19, 2024
Merged

tapchannel: use defer to ensure lease unlocked if funding failure #1033

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74 changes: 50 additions & 24 deletions tapchannel/aux_funding_controller.go
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Original file line number Diff line number Diff line change
Expand Up @@ -505,6 +505,9 @@ func (p *pendingAssetFunding) unlockInputs(ctx context.Context,
func (p *pendingAssetFunding) unlockAssetInputs(ctx context.Context,
coinSelect tapfreighter.CoinSelector) error {

log.Debugf("unlocking asset inputs: %v",
spew.Sdump(p.lockedAssetInputs))

err := coinSelect.ReleaseCoins(ctx, p.lockedAssetInputs...)
if err != nil {
return fmt.Errorf("unable to unlock asset outpoints %v: %w",
Expand Down Expand Up @@ -1028,13 +1031,6 @@ func (f *FundingController) completeChannelFunding(ctx context.Context,
return nil, err
}

fundingState.lockedAssetInputs = fn.Map(
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@Roasbeef Roasbeef Jul 19, 2024 •
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I moved this down (called earlier) so we track the locked inputs as soon as the initial vPSBT funding finishes.

fundedVpkt.VPacket.Inputs,
func(in *tappsbt.VInput) wire.OutPoint {
return in.PrevID.OutPoint
},
)

// Now that we have the initial skeleton for our funding PSBT, we'll
// modify the output value to match the channel amt asked for, which
// lnd will expect.
Expand Down Expand Up @@ -1356,6 +1352,40 @@ func (f *FundingController) processFundingReq(fundingFlows fundingFlowIndex,
return fmt.Errorf("unable to fund vPacket: %w", err)
}

// Now that we've funded the vPk, keep track of the set of inputs we
// locked to ensure we unlock them later.
fundingState.lockedAssetInputs = fn.Map(
fundingVpkt.VPacket.Inputs,
func(in *tappsbt.VInput) wire.OutPoint {
return in.PrevID.OutPoint
},
)

// We'll use this closure to ensure that we'll always unlock the inputs
// if we encounter an error below.
unlockLeases := func() {
err := fundingState.unlockInputs(fundReq.ctx, f.cfg.ChainWallet)
if err != nil {
log.Errorf("unable to unlock inputs: %v", err)
}

err = fundingState.unlockAssetInputs(
fundReq.ctx, f.cfg.CoinSelector,
)
if err != nil {
log.Errorf("Unable to unlock asset inputs: %v", err)
}
}

// Register a defer to execute if none of the set up below succeeds.
// This ensure we always unlock the UTXO.
var setupSuccess bool
defer func() {
if !setupSuccess {
unlockLeases()
}
}()

// Now that we know the final funding asset root along with the splits,
// we can derive the tapscript root that'll be used alongside the
// internal key (which we'll only learn from lnd later as we finalize
Expand Down Expand Up @@ -1394,12 +1424,23 @@ func (f *FundingController) processFundingReq(fundingFlows fundingFlowIndex,
"proofs: %w", err)
}

setupSuccess = true

// With the ownership proof sent, we'll now spawn a goroutine to take
// care of the final funding steps.
f.Wg.Add(1)
go func() {
defer f.Wg.Done()

// If we've failed, then we'll unlock any of the locked
// UTXOs, so they're free again.
var completeSuccess bool
defer func() {
if !completeSuccess {
unlockLeases()
}
}()

log.Infof("Waiting for funding ack...")

// Before we proceed with the channel funding, we'll wait to
Expand All @@ -1426,23 +1467,6 @@ func (f *FundingController) processFundingReq(fundingFlows fundingFlowIndex,
fundReq.ctx, fundingState, fundingVpkt,
)
if err != nil {
// If we've failed, then we'll unlock any of the locked
// UTXOs, so they're free again.
uErr := fundingState.unlockInputs(
fundReq.ctx, f.cfg.ChainWallet,
)
if uErr != nil {
log.Errorf("unable to unlock inputs: %v", uErr)
}

uErr = fundingState.unlockAssetInputs(
fundReq.ctx, f.cfg.CoinSelector,
)
if uErr != nil {
log.Errorf("Unable to unlock asset inputs: %v",
uErr)
}

// If anything went wrong during the funding process,
// the remote side might have an in-memory state and
// wouldn't allow us to try again within the next 10
Expand All @@ -1460,6 +1484,8 @@ func (f *FundingController) processFundingReq(fundingFlows fundingFlowIndex,
return
}

completeSuccess = true

fundReq.respChan <- chanPoint
}()

Expand Down
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