This commit removes shadowing of the currentHeight
variable when registering for neutrino spend
notifications. Currently, a locally scoped variable
is used when determining if the backend is fully
synced before attempting to call GetUtxo, which
means that the variable won't be updated after
breaking out of the loop. As a result, this could
cause us to scan unnecessarily if the backend is
catching up, e.g. after being offline for some time.
After joining the two forked chains, it is necessary to ensure they both agree on the same best hash before proceeding to UnsafeStart the notifier.
This is because when the BitcoindClient starts, it retrieves its best known block then calls GetBlockHeaderVerbose on the hash of the retrieved block. This block could be a reorged block if JoinNodes has not completed sync. If it is the case that the best block retrieved has been reorged out of the chain, GetBlockHeaderVerbose errors because bitcoind sets the number of confirmations to -1 on reorged blocks, and the btcd rpc client panics when parsing a block whose number of confirmations is negative.
This parsing error is expected to be fixed, and as a more permanent solution chain backends should ensure that the `best block` they retrieve during startup has not been reorged out of the chain.
In this commit, we address a bug where it's possible that we still
attempt to manually scan for a transaction to determine whether it's
been included in the chain even after successfully checking the txindex
and not finding it there. Now, we'll short-circuit this process by
exiting early if the txindex lookup was successful but the transaction
in question was not found. Otherwise, we'll fall back to the manual
scan.
In this commit, we extract some of the helper test variables and
functions into their own file and guard them under a build flag. This is
needed as some unit tests will be introduced in a future commit where
most of the same functions within the interface tests are reused. In
order to prevent these variables and functions from being exportable, we
guard them by the "debug" build tag.
rescanning
In this commit, we modify the rescan options Neutrino uses when
performing a rescan for historical chain events to disable disconnected
block notifications. This is needed as the Neutrino backend will mutate
its internal state while rewinding, which causes disconnected block
notifications to be sent. Since the notifier acts upon these
notifications, they would cause it to also rewind unnecessarily.
