This commit is a refactor of how we construct htlcs to make it possible
to pass in internal keys for the sender and receiver when creating P2TR
htlcs. Furthermore the commit also cleans up constructors to not pass in
script versions and output types to make the code more readable.
In this commit we deprecate the sighash field from the
MuSig2SignSweepReq request in favour of using a psbt serialized sweep
transaction instead. This way the sever gains full transparency about
client sweep requests and can assemble the sighash to sign on its own.
This commit adds optional cooperative musig2 sweep by calling the server
to create a partial signature for the sweep if we'd otherwise be allowed
to spend the htlc. If the cooperative musig2 spend fails, we always fall
back to use the scriptpath spend.
Taproot spends require a different sighash, so we update our HtlcScript
interface to provide the appropriate sighash when sweeping. We also add
distinct Timeout/Success Script functions to allow for tapleaf spends
which have different locking scripts for different paths. Note that the
timeout and success paths will be the same for segwit v0 htlcs, because
it has a single branched script containing all spend paths.
In future iterations, this differentiation of claim scripts can also
be used to use musig2 to collaboratively keyspend P2TR htlcs with the
server. This script can be expressed as PriorityScript (because we'll
try to keyspend as a priority, and then fall back to a tap leaf spend).
As we've done here, segwit v0 spends would just return their single
script for PriorityScript, and the claim would be no different from
our other claims.
Formatting our error was stifling any grpc error returned by the
server. Instead, we bubble up our grpc error, setting an unknown
code if the server did not specifically return an error code.
We're going to want more information about our failures going
forward, so we refactor payInvoice to return a full payment
status. The primary change in this commit is that we surface
both types of payment failures (result.err when we fail immediately,
and lnrpc.Failure when our payment is failed back) and return them
in the failure() method, rather than combining this information
at a lower level.
We update to the latest lndclient that now requires a label when
publishing an on-chain transaction. Instead of just adding an empty
string, we use the proper labels added in a previous commit.
Previously labels with reserved prefixes were added to provide us
with a way to identify automatically dispatched loops. This commit moves
the validation of these labels to the rpc level so that it will only
apply to user-initiated swaps.
This commit bumps the current protocol version and integrates htlc v2
with loop in/out for new swaps, while keeping htlc v1 for any pending
swaps with previous protocol versions.
To allow users to specify differing confirmation targets, we store the
swap conf target per-swap. This makes us restart safe, so we do not
forget confirmation values for swaps that are in flight when we restart.
This commits adds an optional label to our swaps, and writes it to
disk under a separate key in our swap bucket. This approach is chosen
rather than an on-the-fly addition to our existing swap contract field
so that we do not need to deal with EOF checking in the future. To allow
creation of unique internal labels, we add a reserved prefix which can
be used by the daemon to set labels that are distinct from client set
ones.
Once we have revealed our preimage to the world with a sweep attempt,
we can safely push our preimage to the server to speed up on chain
claim.
Rather than rely on the server, we use the state of our invoice in lnd
to determine whether we should continue trying to push the preimage to
the server.
This commit extends SwapResponse and SwapStatus with np2wsh and p2wsh
htlc output addresses to support both nested and native segwit htlcs
in loop-in.
Furthermore the commit adds support for native segwith loop-in htlcs.
When the htlc is paid internally, as of this commit we'll use NP2WSH,
otherwise users are free to select whether to pay the NP2WSH or the
P2WSH htlc.
