v0.0.101

API Updates

• Custom message types are now supported directly in the PeerManager,
  allowing you to send and receive messages of any type that is not natively
  understood by LDK. This requires a new type bound on PeerManager, a
  CustomMessageHandler. IgnoringMessageHandler provides a simple default
  for this new bound for ignoring unknown messages (#1031, #1074).
• Route graph updates as a result of failed payments are no longer provided as
  MessageSendEvent::PaymentFailureNetworkUpdate but instead included in a
  new field in the Event::PaymentFailed events. Generally, this means route
  graph updates are no longer handled as a part of the PeerManager but
  instead through the new EventHandler implementation for
  NetGraphMsgHandler. To make this easy, a new parameter to
  lightning-background-processor::BackgroundProcessor::start is added, which
  contains an Optional NetGraphmsgHandler. If provided as Some, relevant
  events will be processed by the NetGraphMsgHandler prior to normal event
  handling (#1043).
• NetworkGraph is now, itself, thread-safe. Accordingly, most functions now
  take &self instead of &mut self and the graph data can be accessed
  through NetworkGraph.read_only (#1043).
• The balances available on-chain to claim after a channel has been closed are
  now exposed via ChannelMonitor::get_claimable_balances and
  ChainMonitor::get_claimable_balances. The second can be used to get
  information about all closed channels which still have on-chain balances
  associated with them. See enum variants of ln::channelmonitor::Balance and
  method documentation for the above methods for more information on the types
  of balances exposed (#1034).
• When one HTLC of a multi-path payment fails, the new field all_paths_failed
  in Event::PaymentFailed is set to false. This implies that the payment
  has not failed, but only one part. Payment resolution is only indicated by an
  Event::PaymentSent event or an Event::PaymentFailed with
  all_paths_failed set to true, which is also set for the last remaining
  part of a multi-path payment (#1053).
• To better capture the context described above, Event::PaymentFailed has
  been renamed to Event::PaymentPathFailed (#1084).
• A new event, ChannelClosed, is provided by ChannelManager when a channel
  is closed, including a reason and error message (if relevant, #997).
• lightning-invoice now considers invoices with sub-millisatoshi precision
  to be invalid, and requires millisatoshi values during construction (thus
  you must call amount_milli_satoshis instead of amount_pico_btc, #1057).
• The BaseSign interface now includes two new hooks which provide additional
  information about commitment transaction signatures and revocation secrets
  provided by our counterparty, allowing additional verification (#1039).
• The BaseSign interface now includes additional information for cooperative
  close transactions, making it easier for a signer to verify requests (#1064).
• Route has two additional helper methods to get fees and amounts (#1063).
• Txid and Transaction objects can now be deserialized from responses when
  using the HTTP client in the lightning-block-sync crate (#1037, #1061).

Bug Fixes

• Fix a panic when reading a lightning invoice with a non-recoverable
  signature. Further, restrict lightning invoice parsing to require payment
  secrets and better handle a few edge cases as required by BOLT 11 (#1057).
• Fix a panic when receiving multiple messages (such as HTLC fulfill messages)
  after a call to chain::Watch::update_channel returned
  Err(ChannelMonitorUpdateErr::TemporaryFailure) with no
  ChannelManager::channel_monitor_updated call in between (#1066).
• For multi-path payments, Event::PaymentSent is no longer generated
  multiple times, once for each independent part (#1053).
• Multi-hop route hints in invoices are now considered in the default router
  provided via get_route (#1040).
• The time peers have to respond to pings has been increased when building
  with debug assertions enabled. This avoids peer disconnections on slow hosts
  when running in debug mode (#1051).
• The timeout for the first byte of a response for requests from the
  lightning-block-sync crate has been increased to 300 seconds to better
  handle the long hangs in Bitcoin Core when it syncs to disk (#1090).

Serialization Compatibility

• Due to a bug in 0.0.100, Events written by 0.0.101 which are of a type not
  understood by 0.0.100 may lead to Err(DecodeError::InvalidValue) or corrupt
  deserialized objects in 0.100. Such Events will lead to an
  Err(DecodeError::InvalidValue) in versions prior to 0.0.100. The only such
  new event written by 0.0.101 is Event::ChannelClosed (#1087).
• Payments that were initiated in versions prior to 0.0.101 may still
  generate duplicate PaymentSent Events or may have spurious values for
  Event::PaymentPathFailed::all_paths_failed (#1053).
• The return values of ChannelMonitor::get_claimable_balances (and, thus,
  ChainMonitor::get_claimable_balances) may be spurious for channels where
  the spend of the funding transaction appeared on chain while running a
  version prior to 0.0.101. Balance information should only be relied upon
  for channels that were closed while running 0.0.101+ (#1034).
• Payments failed while running versions prior to 0.0.101 will never have a
  Some for the network_update field (#1043).

In total, this release features 67 files changed, 4980 insertions, 1888
deletions in 89 commits from 12 authors, in alphabetical order:

• Antoine Riard
• Devrandom
• Galder Zamarreño
• Giles Cope
• Jeffrey Czyz
• Joseph Goulden
• Matt Corallo
• Sergi Delgado Segura
• Tibo-lg
• Valentine Wallace
• abhik-99
• vss96