Require `WithContext` log wrappers on `OutboundPayments` calls and pass payment hashes #4342

TheBlueMatt · 2026-01-25T16:18:58Z

In much of LDK we pass around `Logger` objects both to avoid having
to `Clone` `Logger` `Deref`s (soon to only be `Logger`s) and to
allow us to set context with a wrapper such that any log calls on
that wrapper get additional useful metadata in them.

Sadly, when we added a `Logger` type to `OutboundPayments` we broke
the ability to do the second thing - payment information logged
directly or indirectly via logic in the `OutboundPayments` has no
context making log-searching rather challenging.

Here we move to instead using the automated `add_logging`
proc-macro to require that `OutboundPayment` functions receive a
`WithContext` logger, appropriately setting (especially) the
`payment_hash` as we do so.

Fixes #4307

I believe the first three commits can/should be backported to 0.2. Ideally we'd also backports a variant to 0.1 to fix #4307 there but I'm not really sure its quite worth it to write a whole new version just for 0.1.

ldk-reviews-bot · 2026-01-25T16:19:01Z

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codecov · 2026-01-25T18:18:23Z

Codecov Report

❌ Patch coverage is 88.26087% with 27 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.09%. Comparing base (7fe3268) to head (91e4354).

Files with missing lines	Patch %	Lines
lightning/src/ln/outbound_payment.rs	85.40%	12 Missing and 8 partials ⚠️
lightning/src/ln/channelmanager.rs	86.53%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##           main    #4342       +/-   ##
=========================================
+ Coverage      0   86.09%   +86.09%     
=========================================
  Files         0      156      +156     
  Lines         0   102526   +102526     
  Branches      0   102526   +102526     
=========================================
+ Hits          0    88273    +88273     
- Misses        0    11757    +11757     
- Partials      0     2496     +2496

Flag	Coverage Δ
tests	`86.09% <88.26%> (?)`

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TheBlueMatt · 2026-01-26T13:06:29Z

Planning to backport to 0.2 in #4344

wpaulino

Code LGTM though I'm not really a fan of the hidden logger argument.

ldk-reviews-bot · 2026-01-26T18:35:14Z

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ldk-reviews-bot · 2026-01-26T18:35:28Z

✅ Added second reviewer: @valentinewallace

TheBlueMatt · 2026-01-26T19:14:47Z

I'm not really a fan of the hidden logger argument.

I could go either way. It seems like an easy way to ensure we always have the logger which will make @joostjager happy, and in this case its fairly straightforward (because we're not trying to automate passing the logger from ChannelManager).

valentinewallace

I'm not really into this juice vs squeeze ratio. I think @joostjager should take a look since it's supposed to make him happy :) If it really does, I guess it's fine.

Mentioned to Matt offline but Claude pointed out that the visit-mut syn feature allows removing ~all the boilerplate.

joostjager

Appreciate the attempt, but I don't think this is the right direction. The macro adds a layer of complexity, and the hidden logger argument that gets silently injected into every self.*() call isn't very intuitive. I agree with @wpaulino and @valentinewallace's hesitation.

My preference would still be to keep exploring something similar to what the tracing crate does with the context. For no-std the developer experience might not be optimal, but I still think that is a reasonable trade-off.

If that is unacceptable, I think we're better off sticking with explicit logger parameters and types. At least the code does what it says.

TheBlueMatt · 2026-01-27T20:08:26Z

Alrighty, explicit loggers it is.

In `ChannelMonitor` logging, we often wrap a logger with `WithChannelMonitor` to automatically include metadata in our structured logging. That's great, except having too many logger wrapping types flying around makes for less compatibility if we have methods that want to require a wrapped-logger. Here we change the `WithChannelMonitor` "constructors" to actually return a `WithContext` instead, making things more consistent.

In much of LDK we pass around `Logger` objects both to avoid having to `Clone` `Logger` `Deref`s (soon to only be `Logger`s) and to allow us to set context with a wrapper such that any log calls on that wrapper get additional useful metadata in them. Sadly, when we added a `Logger` type to `OutboundPayments` we broke the ability to do the second thing - payment information logged directly or indirectly via logic in the `OutboundPayments` has no context making log-searching rather challenging. Here we fix this by retunring to passing loggers explicitly to `OutboundPayments` methods that need them, specifically requiring `WithContext` wrappers to ensure the callsite sets appropriate context on the logger. Fixes lightningdevkit#4307

While `PaymentHash`es are great for searching logs, in the case of BOLT 12 the hash isn't selected until well into the payment process. Thus, its important that we allow for filtering by `PaymentId` as well to ensure payment-related logs are always reliably searchable.

TheBlueMatt · 2026-01-28T14:09:57Z

Had to rebase for a trivial conflict.

valentinewallace

LGTM. I think CI is still sad

valentinewallace · 2026-01-28T16:31:38Z

lightning/src/ln/channelmanager.rs


 	fn abandon_payment_with_reason(&self, payment_id: PaymentId, reason: PaymentFailureReason) {
 		let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);
+


nit: spurious newline

valentinewallace · 2026-01-28T16:33:21Z

lightning/src/ln/channelmanager.rs

 		// being fully configured. See the docs for `ChannelManagerReadArgs` for more.
 		match source {
 			HTLCSource::OutboundRoute { ref path, ref session_priv, ref payment_id, .. } => {
+				let logger = WithContext::from(&self.logger, None, None, Some(*payment_hash));


It might make sense to use the first-hop channel_id/peer here, similarly for claims below

Oh it is done but in the last commit.

valentinewallace · 2026-01-28T16:35:31Z

lightning/src/ln/channelmanager.rs

 									&prev_hop_data,
 									"HTLC already forwarded to the outbound edge",
-									&args.logger,
+									&&logger,


nit: here and some other places below don't really fit into this commit which is specific to outbound_payments calls

valentinewallace · 2026-01-28T16:58:08Z

lightning/src/util/logger.rs

+		if self.payment_id.is_some() {
+			record.payment_id = self.payment_id;
+		}


Somewhat pre-existing, but could it be worth checking that we're not overriding an already set field with a different field here?

TheBlueMatt added the backport 0.2 label Jan 25, 2026

ldk-reviews-bot requested a review from wpaulino January 25, 2026 16:29

TheBlueMatt force-pushed the 2026-01-decode-log-payment-hash branch from 3ca1fbd to ad93b8d Compare January 25, 2026 16:51

TheBlueMatt mentioned this pull request Jan 25, 2026

[0.1] Backport #4341 and cut 0.1.9 #4343

Merged

valentinewallace mentioned this pull request Jan 26, 2026

[0.2] Backports and cut 0.2.1 #4344

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TheBlueMatt dismissed wpaulino’s stale review via 5759a10 January 27, 2026 17:34

TheBlueMatt force-pushed the 2026-01-decode-log-payment-hash branch from ad93b8d to 5759a10 Compare January 27, 2026 17:34

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TheBlueMatt force-pushed the 2026-01-decode-log-payment-hash branch from 5759a10 to f50c6a6 Compare January 27, 2026 20:08

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TheBlueMatt force-pushed the 2026-01-decode-log-payment-hash branch 3 times, most recently from 8508cf3 to 5e5c54a Compare January 27, 2026 20:13

TheBlueMatt mentioned this pull request Jan 27, 2026

Drop Deref indirection for most trait parameters #4311

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		fn abandon_payment_with_reason(&self, payment_id: PaymentId, reason: PaymentFailureReason) {
		let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self);

Require WithContext log wrappers on OutboundPayments calls and pass payment hashes #4342

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Require `WithContext` log wrappers on `OutboundPayments` calls and pass payment hashes #4342

Require `WithContext` log wrappers on `OutboundPayments` calls and pass payment hashes #4342

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