While there is no great way to handle a true failure to persist a
`ChannelMonitorUpdate`, it is confusing for users for there to be
no error variant at all on an I/O operation.
Thus, here we re-add the error variant removed over the past
handful of commits, but rather than handle it in a truly unsafe
way, we simply panic, optimizing for maximum mutex poisoning to
ensure any future operations fail and return immediately.
In the future, we may consider changing the handling of this to
instead set some "disconnect all peers and fail all operations"
bool to give the user a better chance to shutdown in a semi-orderly
fashion, but there's only so much that can be done in lightning if
we truly cannot persist new updates.
When a `ChannelMonitorUpdate` fails to apply, it generally means
we cannot reach our storage backend. This, in general, is a
critical issue, but is often only a transient issue.
Sadly, users see the failure variant and return it on any I/O
error, resulting in channel force-closures due to transient issues.
Users don't generally expect force-closes in most cases, and
luckily with async `ChannelMonitorUpdate`s supported we don't take
any risk by "delaying" the `ChannelMonitorUpdate` indefinitely.
Thus, here we drop the `PermanentFailure` variant entirely, making
all failures instead be "the update is in progress, but won't ever
complete", which is equivalent if we do not close the channel
automatically.
Firstly, we switch our BP over to use `FilesystemStore`, which also gives us test
coverage and ensures the compatibility.
Then, we remove the superseded `KVStorePersister` trait and
the `FilesystemPersister` code.
Rather than using the std benchmark framework (which isn't
maintained and is unlikely to get any further maintenance), we swap
for criterion, which at least gets us a variable number of test
runs so our benchmarks don't take forever.
We also fix the RGS benchmark to pass now that the file in use is
stale compared to today's date.
`rust-bitcoin v0.30.0` introduces concrete variants for data members of
block `Header`s. To avoid having to update these across every use, we
introduce new helpers to create dummy blocks and headers, such that the
update process is a bit more straight-forward.
This is largely motivated by some follow-up work for anchors that will
introduce an event handler for `BumpTransaction` events, which we can
now include in this new top-level `events` module.
Currently, all that is required to force close a channel is to broadcast
either of the available commitment transactions, but this changes with
anchor outputs – commitment transactions may need to have
additional fees attached in order to confirm in a timely manner. While
we may be able to just queue a new update using the channel's next
available update ID, this may result in a violation of the
`ChannelMonitor` API (each update ID must strictly increase by 1) if the
channel had updates that were persisted by its `ChannelMonitor`, but not
the `ChannelManager`. Therefore, we choose to re-purpose the existing
`CLOSED_CHANNEL_UPDATE_ID` update ID to also apply to
`ChannelMonitorUpdate`s that will force close their respective channel
by broadcasting the holder's latest commitment transaction.
This is purely a refactor that does not change the InitFeatures
advertised by a ChannelManager. This allows users to configure which
features should be advertised based on the values of `UserConfig`. While
there aren't any existing features currently leveraging this behavior,
it will be used by the upcoming anchors_zero_fee_htlc_tx feature.
The UserConfig dependency on provided_init_features caused most
callsites of the main test methods responsible for opening channels to
be updated. This commit foregos that completely by no longer requiring
the InitFeatures of each side to be provided to these methods. The
methods already require a reference to each node's ChannelManager to
open the channel, so we use that same reference to obtain their
InitFeatures. A way to override such features was required for some
tests, so a new `override_init_features` config option now exists on
the test harness.
When a `chain::Watch` `ChannelMonitor` update method is called, the
user has three options:
(a) persist the monitor update immediately and return success,
(b) fail to persist the monitor update immediately and return
failure,
(c) return a flag indicating the monitor update is in progress and
will complete in the future.
(c) is rather harmless, and in some deployments should be expected
to be the return value for all monitor update calls, but currently
requires returning `Err(ChannelMonitorUpdateErr::TemporaryFailure)`
which isn't very descriptive and sounds scarier than it is.
Instead, here, we change the return type used to be a single enum
(rather than a Result) and rename `TemporaryFailure`
`UpdateInProgress`.
As we move towards specify supported/required feature bits in the
module(s) where they are supported, the global `known` feature set
constructors no longer make sense.
Here we stop relying on the `known` method in the
`lightning-background-processor` and `lightning-persister` crate
tests.
If a user restores from a backup that they know is stale, they'd
like to force-close all of their channels (or at least the ones
they know are stale) *without* broadcasting the latest state,
asking their peers to do so instead. This simply adds methods to do
so, renaming the existing `force_close_channel` and
`force_close_all_channels` methods to disambiguate further.
