This commit introduces a new test case that asserts all of the witness
size constants currently in the codebase. We also reintroduce the
AcceptedHtlcSuccessWitnessSize and OfferedHtlcTimeoutWitnessSize
constants that were recently removed for the sake of completeness.
In asserting the witnes sizes, there were three uncovered discrepancies:
* OfferedHtlcSuccessWitnessSize overestimated by about 30% because it
included an extra signature in the calculation.
* ToLocalPenaltyWitnessSize was underestimated by one byte, because it
was missing the length byte for the OP_TRUE. This has implications
the watchtower protocol since the client and server are assumed to
share the same weight estimates used for signing. This commit keeps
the current behavior, with the intention of rolling out negotiation
for which weight estimate to use for a given session.
* AcceptedHtlcScriptSize was underestimated by one byte because it was
missing a length byte for the value 32 pushed on the stack when
asserting the preimage's length. This affects all AcceptedHtlc*
witness sizes.
This commit introduces the Signature interface which will be used by our
witness construction methods instead of passing in raw byte slices. This
will be used later to inject various kinds of mock signatures, e.g.
73-byte signatures for simulating worst-case witness weight.
We also increase the witness size for these types to account for the 3
extra bytes. The size won't be correct in all cases, but it is just an
upper bound in any case.
To be able to change more than the witness used for each test case, we
extract commit and sweep tx generation into own methods that can be
called from each test case.
We do the same for TestHTLCReceiverSpendValidation
This fixes an error case that wouldn't have been caught, since
vm.Execute applies more rules than the individual steps (most notably
the clean stack rule).
Instead we execute the engine as normal, and only step through if we
decide that the outcome is unexpected.
Since we never attempt to sweep an HTLC we offered with the preimage on
the remote's commitment, we never use the constant
AcceptedHtlcSuccessWitnessSize for weight estimation. Similarly, we
never timout an HTLC offered by the remote on our own commitment, and
don't need the constant OfferedHtlcTimeoutWitnessSize.
This commit corrects a bug in TxWeightEstimator that could result in
underestimations for transactions involving NestedP2WPKH and NestedP2WSH
inputs. The scriptSig data push is now accounted for in a proper size
constant, and the input count is now incremented in both. This would
only be detectable in the event that the number of non-nested inputs and
the total number of inputs straddle the discontinuities in the
CompactSize encoding, e.g. 253, 2^16-1, or 2^32-1.
In this commit, we update the `CommitSpendNoDelay` method to be aware of
the alternate spending mechanism for commitments that don't have a tweak
for the remote party's non-delay output. We also add a new witness type
so callers can convey their expected signing path.
This commit is a step to split the lnwallet package. It puts the Input
interface and implementations in a separate package along with all their
dependencies from lnwallet.
