Upgrade `uniffi` dependency to v0.29.5 switch to proc macros (mostly) by tnull · Pull Request #812 · lightningdevkit/ldk-node

tnull · 2026-02-27T11:27:50Z

We here upgrade to uniffi v0.29.5. This upgrade requires a few changes and workarounds, in particular UniffiCustomTypeConverter are gone and replaced with corresponding macros. (see uniffi-rs CHANGELOG). We also had to find workarounds for remote enum interface definitions, and discovered that uniffi lost the ability to use remote trait interfaces (see mozilla/uniffi-rs#2823).

The latter therefore requires us to add some duplicative code as we added a local copy of VssHeaderProvider/VssHeaderProviderError and used an adaptor to make it work for the bindings side of the builder.

Since we've now already utilized the newer proc macro approach to make this work, we also included a list of commits that switch over some types from the manual definitions in the UDL file to have the bindings auto-derived via the proc macros, which will reduce maintenance overhead going forward. It also means that we will finally get docstrings working in the target language, which is another big win.

Changeset looks large, but most of it are code moves (especially in the last commit) as we split some of the impl blocks into parts that are exposed and parts that are not exposed via uniffi-procmacros.

Best reviewed with:

git diff --diff-algorithm=patience --color-moved --color-moved-ws=ignore-all-space

(cc @vincenzopalazzo)

ldk-reviews-bot · 2026-02-27T11:27:53Z

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We here upgrade to `uniffi` v0.29.5. This upgrade requires a few changes and workarounds, in particular `UniffiCustomTypeConverter` are gone and replaced with corresponding macros. We also had to find workarounds for remote enum interface definitions, and discovered that `uniffi` lost the ability to use remote trait interfaces. The latter therefore requires us to add some duplicative code as we added a local copy of `VssHeaderProvider`/`VssHeaderProviderError` and used an adaptor to make it work for the bindings side of the builder.

Migrate `WordCount`, `PaymentDirection`, `PaymentStatus`, and `AsyncPaymentsRole` from UDL enum definitions to proc-macro `#[derive(uniffi::Enum)]` on their Rust source types, replacing the UDL definitions with `typedef enum` references. Generated with the help of AI (Claude Code). Co-Authored-By: HAL 9000

Add `#[derive(uniffi::Error)]` to `EntropyError` and `BuildError`, replacing their UDL definitions with `typedef enum` references. Generated with the help of AI (Claude Code). Co-Authored-By: HAL 9000

Migrate `MaxDustHTLCExposure`, `ConfirmationStatus`, `PaymentKind`, `LightningBalance`, and `PendingSweepBalance` enums, as well as the `LSPFeeLimits` record, from UDL definitions to proc-macro derives. Co-Authored-By: HAL 9000

Migrate `Config`, `AnchorChannelsConfig`, `BackgroundSyncConfig`, `SyncTimeoutsConfig`, `EsploraSyncConfig`, `ElectrumSyncConfig`, `ChannelConfig`, `CustomTlvRecord`, `PeerDetails`, `PaymentDetails`, `BalanceDetails`, `NodeStatus`, `LSPS2ServiceConfig`, and `ChannelDetails` from UDL dictionary definitions to `#[derive(uniffi::Record)]` proc-macro exports. Co-Authored-By: HAL 9000

Migrate `Bolt11InvoiceDescription`, `OfferAmount`, `UnifiedPaymentResult`, `RouteHintHop`, `LogRecord`, `LSPS1PaymentInfo`, `LSPS1Bolt11PaymentInfo`, `LSPS1OnchainPaymentInfo`, `ChannelInfo`, `ChannelUpdateInfo`, `NodeInfo`, `NodeAnnouncementInfo`, and `VssHeaderProviderError` from UDL definitions to proc-macro derives. Co-Authored-By: HAL 9000

…s to UniFFI proc-macro export Move these three simple Object types from UDL interface definitions to `#[derive(uniffi::Object)]` + `#[uniffi::export]` proc-macro annotations, replacing their UDL interface blocks with `typedef interface` references. Generated with the assistance of AI (Claude). Co-Authored-By: HAL 9000

Migrate `Bolt11Invoice`, `Offer`, `HumanReadableName`, `Refund`, and `Bolt12Invoice` from UDL interface definitions to proc-macro derives (`uniffi::Object`) with `#[uniffi::export]` on impl blocks and `#[uniffi::constructor]` on constructors. For types with `[Traits=(Debug, Display, Eq)]`, use `#[uniffi::export(Debug, Display, Eq)]` on the struct. Replace UDL interface definitions with `typedef interface` references. Co-Authored-By: HAL 9000

Migrate `Bolt11Payment`, `Bolt12Payment`, `SpontaneousPayment`, `OnchainPayment`, and `UnifiedPayment` from UDL interface definitions to UniFFI proc-macro export. For each payment struct, split the impl block so that `pub(crate)` and private helper methods remain in a plain impl block while all `pub fn` methods are placed in a `#[cfg_attr(feature = "uniffi", uniffi::export)]` impl block. For `Bolt12Payment`, the cfg-gated `set_paths_to_static_invoice_server` and `blinded_paths_for_async_recipient` methods are placed in separate `#[cfg(not(feature = "uniffi"))]` and `#[cfg(feature = "uniffi")] #[uniffi::export]` impl blocks to avoid proc-macro conflicts. Replace the full interface definitions in the UDL with `typedef interface` one-liners and remove the now-unused `UnifiedPaymentResult` re-export from `ffi/types.rs`. This commit was made with assistance from an AI tool (Claude Code). Co-Authored-By: HAL 9000

With the migration to UniFFI proc-macro exports, many typedefs in the UDL file are no longer needed as their types are only referenced by other proc-macro-defined types. Remove 30 non-custom typedefs that are not directly referenced by any fully UDL-defined type (interfaces, traits, remote types, or namespace functions). Note: `[Custom]` typedefs must be retained as the binding generator needs them regardless of whether the type appears in UDL signatures. Generated with the assistance of an AI coding tool. Co-Authored-By: HAL 9000

tnull · 2026-02-27T15:03:29Z

Failure of the VSS CI is pre-existing and hence expected.

jkczyz · 2026-02-27T23:04:14Z

src/ffi/types.rs

+/// Errors around providing headers for each VSS request.
+#[derive(Debug)]
+pub enum VssHeaderProviderError {


May want to leave a comment on why these are duplicated or if they need to be kept in sync. Or would we just get a compilation error? Likewise for other enums.

Doc changes won't be directly detected, but actual signature changes would due to the match statements below.

jkczyz · 2026-02-27T23:14:45Z

src/ffi/types.rs

+impl From<VssHeaderProviderError> for VssClientHeaderProviderError {
+	fn from(e: VssHeaderProviderError) -> Self {
+		match e {
+			VssHeaderProviderError::InvalidData { error } => {
+				VssClientHeaderProviderError::InvalidData { error }
+			},
+			VssHeaderProviderError::RequestError { error } => {
+				VssClientHeaderProviderError::RequestError { error }
+			},
+			VssHeaderProviderError::AuthorizationError { error } => {
+				VssClientHeaderProviderError::AuthorizationError { error }
+			},
+			VssHeaderProviderError::InternalError { error } => {
+				VssClientHeaderProviderError::InternalError { error }
+			},
+		}
+	}
+}


I take it wrapping the underlying enum and providing From doesn't really help clients needing to use a variant?

Ah, yes. I initially also attempted to just keep using the upstream/remote enum, but couldn't make it work for now. I hope we can drop all of the copied code as soon as mozilla/uniffi-rs#2823 is resolved.

jkczyz · 2026-02-27T23:23:48Z

src/payment/bolt11.rs

 		Ok(maybe_wrap(invoice))
 	}

-	pub(crate) fn receive_inner(


Could just use multiple impl blocks to avoid the code moves, fwiw.

True, though that might be more confusing w.r.t. what's exposed and what not going forward.

tnull · 2026-03-02T07:46:44Z

Going ahead an landing this to avoid any potential rebase conflicts, happy to address feedback in a follow-up if we think it should be addressed.

tnull force-pushed the 2026-01-bump-to-uniffi-0.29 branch from 8f4909a to a6f5d63 Compare February 27, 2026 13:49

tnull added 9 commits February 27, 2026 15:00

Migrate EntropyError and BuildError to UniFFI proc-macro export

0b180e9

Add `#[derive(uniffi::Error)]` to `EntropyError` and `BuildError`, replacing their UDL definitions with `typedef enum` references. Generated with the help of AI (Claude Code). Co-Authored-By: HAL 9000

tnull force-pushed the 2026-01-bump-to-uniffi-0.29 branch from a6f5d63 to 18699d3 Compare February 27, 2026 14:00

tnull requested a review from joostjager February 27, 2026 14:01

tnull changed the title ~~Upgrade uniffi dependency to v0.29.5~~ Upgrade uniffi dependency to v0.29.5 switch to proc macros (mostly) Feb 27, 2026

tnull requested review from jkczyz and removed request for joostjager February 27, 2026 14:56

jkczyz approved these changes Feb 27, 2026

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tnull merged commit 6ae19dd into lightningdevkit:main Mar 2, 2026
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Upgrade `uniffi` dependency to v0.29.5 switch to proc macros (mostly)#812

Upgrade `uniffi` dependency to v0.29.5 switch to proc macros (mostly)#812
tnull merged 10 commits intolightningdevkit:mainfrom
tnull:2026-01-bump-to-uniffi-0.29

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