This commit adds two functional options to the zpay32.Decode function.
`WithKnownFeatureBits` allows the caller to overwrite the default set of
known feature bits used by the function.
`WithErrorOnUnknownFeatureBit` allows the caller to instruct the
function to error out if the invoice that is decoded contaijns unknown
feature bits. We then use this new error-out option from the
`rpcServer`'s `extractPaymentIntent` method.
In this commit, we update the Sig type to support ECDSA and schnorr
signatures. We need to do this as the HTLC signatures will become
schnorr sigs for taproot channels. The current spec draft opts to
overload this field since both the sigs are actually 64 bytes in length.
The only consideration with this move is that callers need to "coerce" a
sig to the proper type if they need schnorr signatures.
This commit was previously split into the following parts to ease
review:
- 2d746f68: replace imports
- 4008f0fd: use ecdsa.Signature
- 849e33d1: remove btcec.S256()
- b8f6ebbd: use v2 library correctly
- fa80bca9: bump go modules
The Core devs decided to us the same bech32 HRP for Signet as is used
for the current Testnet3. This might be okay for on-chain addresses
since they are compatible in theory. But for invoices we want to use a
distinct HRP to distinguish testnet from signet.
Also see spec PR
https://github.com/lightningnetwork/lightning-rfc/pull/844 for more
information about the reasoning.
As a preliminary step to isolating zpay32 in migrations 01-11, we'll
split out the encoding and decoding logic into separate files. Migration
11 only requires invoice decoding, so this prevents us from needing to
copy in the encoding logic that would otherwise be unused.
