rust-lightning

Test restart-claim of two MPP holding cell HTLCs

Test that if we restart and had two inbound MPP-part HTLCs received over the
same channel in the holding cell prior to shutdown, and we lost the holding
cell prior to restart, those HTLCs will still be claimed backwards.

Test largely written by Claude

Fix missing user_channel_id in PaymentForwarded

Previously, if a forwarding node reloaded mid-HTLC-forward with a preimage in
the outbound edge monitor and the outbound edge channel still open, and
subsequently reclaimed the inbound HTLC backwards, the PaymentForwarded event
would be missing the next_user_channel_id field.

Rustfmt ChannelManager::internal_tx_signatures

Accept blinded paths built by a phantom node participant

In the next commit we'll add support for building a BOLT 12 offer
which can be paid to any one of a number of participant nodes. Here
we add support for validating blinded paths as coming from one of
the participating nodes by deriving a new key as a part of the
`ExpandedKey`.

We keep this separate from the existing `ReceiveAuthKey` which is
node-specific to ensure that we only allow this key to be used for
blinded payment paths and contexts in `invoice_request` messages.
This ensures that normal onion messages are still tied to specific
nodes.

Note that we will not yet use the blinded payment path phantom
support which requires additional future work. However, allowing
them to be authenticated in a phantom configuration should allow
for compatibility across versions once the building logic lands.

Add an `ExpandedKey` key for phantom blinded path authentication

In the coming commits we'll add support for building a blinded path
which can be received to any one of several nodes in a "phantom"
configuration (terminology we retain from BOLT 11 though there are
no longer any phantom nodes in the paths).

Here we adda new key in `ExpandedKey` which we can use to
authenticate blinded paths as coming from a phantom node
participant.

Trivial: use full path in test macros

Useful when using these macros in lightning-tests/upgrade_downgrade_tests

Add a read closure to the `legacy` TLV variant

Update the `legacy` TLV read/write variant signature from
`(legacy, $fieldty, $write)` to `(legacy, $fieldty, $read, $write)`,
adding a read closure parameter matching the `custom` variant's
signature.

The read closure is applied in `_check_missing_tlv!` after all TLV
fields are read but before `static_value` fields consume legacy
values. This preserves backwards compatibility with `static_value` and
`default_value` expressions that reference legacy field variables as
`Option<$fieldty>` during TLV reading.

The read closure signature differs from `custom`:
`FnOnce(Option<&$fieldty>) -> Result<(), DecodeError>`. All existing
usage sites return `Ok(())` as their read closure (no-op).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Fix thread starvation in test_single_channel_multiple_mpp

The busy-wait loop polling for PaymentClaimed events had no yield,
causing it to continuously acquire ChannelManager locks via
get_and_clear_pending_events(). This could starve the claim_funds
thread of lock access, preventing it from ever queuing the event.
Add a yield_now() call matching the pattern used by the other two
spin loops in this test.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Add `counterparty_node_id` to `TrackedSpendableOutput`

This adds an optional `counterparty_node_id` field to
`TrackedSpendableOutput` and updates the `track_spendable_outputs`
method signatures on both `OutputSweeper` and `OutputSweeperSync` to
accept this new parameter.

The field uses TLV type 3 (odd) for backwards compatibility. When
reading outputs tracked with LDK 0.2 and prior, this field will be
`None`.

Co-Authored-By: HAL 9000
Signed-off-by: Elias Rohrer <dev@tnull.de>

Make get_latest_mon_update_id a helper on TestChainMonitor

Rename test default channel config

Now that anchor channels are the default,
rename `test_default_anchors_channel_config` to
`test_default_channel_config` and the
previous default to legacy.

Remove automatic channel acceptance

Removes the `manually_accept_inbound_channels` config
option. In upcoming commit we will default to anchor
channels which requires users checking if they have
enough onchain funds to cover fees in case of a force
close. Hence, we move to always require users to
manually accept inbound channels.

Support async signing of interactive-tx initial commitment signatures

This commit allows for an async signer to immediately return upon a call
to `EcdsaChannelSigner::sign_counterparty_commitment` for the initial
commitment signatures of an interactively funded transaction, such that
they can call back in via `ChannelManager::signer_unblocked` once the
signatures are ready. This is done for both splices and dual-funded
channels, though note that the latter still require more work to be
integrated. Since `tx_signatures` must be sent only after exchanging
`commitment_signed`, we make sure to hold them back if they're ready to
be sent until our `commitment_signed` is also ready.

fuzz: fix ChaCha20 encrypt_single_block to preserve data

The fuzzing ChaCha20 implementation's encrypt_single_block was not
copying src to dest, causing encrypted data to be lost (dest remained
zeros). This broke payment flows where metadata is encrypted into
payment_secret - the receiver would decrypt zeros and detect the wrong
payment method (LdkPaymentHash instead of UserPaymentHash), causing
payments to fail with "mismatching preimage".

Fix by making encrypt_single_block copy src to dest (identity
encryption), matching the behavior of the process() method.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Use SignedAmount::unsigned_abs to avoid overflow

In debug mode, using SignedAmount::abs can lead to an integer overflow
when used with SignedAmount::MIN. Use SignedAmount::unsigned_abs to
avoid this.

Fix 0.2 CHANGELOG to note that offers will break on downgrade

It turns out we also switched the key we use to authenticate offers
*created* in the 0.2 upgrade and as a result downgrading to 0.2
will break any offers created on 0.2. This wasn't intentional but
it doesn't really seem worth fixing at this point, so just document
it.

Add AChainMonitor trait and use it in background processor

Add a new `AChainMonitor` trait following the same pattern as
`AChannelManager`. This trait provides associated types for all
generic parameters of `ChainMonitor` and a `get_cm()` method to
access the underlying `ChainMonitor`.

Update the background processor to use `AChainMonitor` trait bounds
instead of spelling out the full `ChainMonitor` generic parameters.
This simplifies the function signatures by removing 5-6 explicit
generic parameters (CF, T, F, P, ES) per function.

This is preparation for adding a flush method to the AChainMonitor
trait.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Add test coverage for `TransactionType::Splice`

Add parallel `txn_types` vector to `TestBroadcaster` to track
`TransactionType` alongside broadcast transactions. Existing
`txn_broadcast()` API remains unchanged for backward compatibility.
New `txn_broadcast_with_types()` API allows tests to verify transaction
types.

Also add a `clear()` helper method and update test files to use it
instead of directly manipulating `txn_broadcasted`, ensuring the two
vectors stay in sync.

Update splice tests to use the new API and verify that splice
transactions are broadcast with the correct `TransactionType`.

Co-Authored-By: HAL 9000
Signed-off-by: Elias Rohrer <dev@tnull.de>

Export `outbound_payments` directly rather than via re-exports

Every time we use re-exports to hide a module in the public API we
end up accidentally breaking the public API due to accidental
seals. We did this yet again in
e9c6bbccc3ccd4cb121a092229f50e29b3345552 where we moved to using a
`CustomTlvs` field in the public API for `RecipientOnionFields` but
forgot to re-export it, making it impossible to use downstream.

Instead, here, we just actually export `outbound_payments`.

Compilation fixes by Claude.

Introduce custom TLVs in `pay_for_bolt11_invoice`

Custom TLVs let the payer attach arbitrary data to the onion packet,
enabling everything from richer metadata to custom authentication on
the payee's side.

Until now, this flexibility existed only through `send_payment`. The
simpler `pay_for_bolt11_invoice` API offered no way to pass custom
TLVs, limiting its usefulness in flows that rely on additional context.

This commit adds custom TLV support to `pay_for_bolt11_invoice`,
bringing it to feature parity.

Drop Deref indirection for NodeSigner

Reduces generics and verbosity across the codebase, should provide equivalent
behavior.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Drop Deref indirection for EntropySource

Reduces generics and verbosity across the codebase, should provide equivalent
behavior.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Support funding_transaction_signed for unfunded dual-funded channels

Now that we require users to first call
`ChannelManager::funding_transaction_signed` before releasing any
signatures, it's possible that it is called before we receive the
initial commitment signed from our counterparty, which would transition
the channel to funded. Because of this, we need to support the API call
while the channel is still in the unfunded phase.

Note that this commit is mostly a code move of
`FundedChannel::funding_transaction_signed` to
`Channel::funding_transaction_signed` that doesn't alter the signing
logic.

Rework ChannelManager::funding_transaction_signed

Previously, we'd emit a FundingTransactionReadyForSigning event once the
initial commitment_signed is exchanged for a splicing/dual-funding
attempt and require users to call back with their signed inputs using
ChannelManager::funding_transaction_signed. While this approach worked
in practice, it prevents us from abandoning a splice if we cannot or no
longer wish to sign as the splice has already been committed to by this
point.

This commit reworks the API such that this is now possible. After
exchanging tx_complete, we will no longer immediately send our initial
commitment_signed. We will now emit the
FundingTransactionReadyForSigning event and wait for the user to call
back before releasing both our initial commitment_signed and our
tx_signatures. As a result, the event is now persisted, as there is only
one possible path in which it is generated. Note that we continue to
only emit the event if a local contribution to negotiated transaction
was made.

Future work will expose a cancellation API such that we can abandon
splice attempts safely (we can just force close the channel with
dual-funding).

fuzz: convert send helpers to closures with node indices

Replace the standalone `send_noret` and `send_hop_noret` functions with
closures defined inside the main loop. This allows them to capture the
`nodes` array and use simple node indices (0, 1, 2) instead of passing
`&nodes[x]` references at each call site.

The `send_payment` and `send_hop_payment` functions are modified to take
pre-computed `PaymentSecret`, `PaymentHash`, and `PaymentId` parameters,
with the closures handling the credential generation. This centralizes
where `PaymentId` is constructed, which will make it easier to add
payment tracking in a future change.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Co-Authored-By: Matt Corallo <git@bluematt.me>