Refactor interactive-tx construction and uses #4123
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
An upcoming commit will include the contributed inputs and outputs in an error whenever ConstructedTransaction::new fails. In order to DRY up that logic, this commit updates the constructor to create the resulting object prior to performing any checks. This way a conversion method can be added that extracts the necessary input and output data.
Both NegotiationContext::validate_tx and ConstructedTransaction::new contain validity checks. Move the former into the latter in order to consolidate the checks in a single place. This will also allow for reusing error construction in an upcoming commit.
|
👋 Thanks for assigning @wpaulino as a reviewer! |
jkczyz
force-pushed
the
2025-09-negotiation-error
branch
from
a7638af to
59f7deb
Compare
Codecov Report❌ Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## main #4123 +/- ##
==========================================
+ Coverage 88.50% 88.59% +0.08%
==========================================
Files 179 180 +1
Lines 134270 134977 +707
Branches 134270 134977 +707
==========================================
+ Hits 118837 119584 +747
+ Misses 12682 12631 -51
- Partials 2751 2762 +11
Flags with carried forward coverage won't be shown. Click here to find out more. ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
|
wpaulino
previously approved these changes
Sep 25, 2025
lightning/src/ln/channel.rs
Outdated
| None => Err(AbortReason::InternalError( | ||
| "Received unexpected interactive transaction negotiation message", | ||
| )), | ||
| None => Err(NegotiationError { |
There was a problem hiding this comment.
Relevant for the follow-up PR: we should be careful to not emit a SpliceFailed event here. We probably only should when pending_splice.is_some().
|
👋 The first review has been submitted! Do you think this PR is ready for a second reviewer? If so, click here to assign a second reviewer. |
Instead of popping each input and output to contribute during an interactive tx session, clone the necessary parts and keep around the original inputs and outputs. This will let us reuse them later when constructing an error. The tradeoff is using additional memory to avoid more code complexity required to extract the sent input and outputs from NegotiationContext.
Currently, only the shared input index is stored in ConstructedTransaction. This will be used later to filter out the shared input when constructing an error during interactive tx negotiation. Store the shared output index as well so that the shared output can be filtered out as well.
The number of inputs allowed during an interactive-tx construction session is limited to 4096, so a u16 can be used instead of u32 when serializing ConstructedTransaction.
jkczyz
force-pushed
the
2025-09-negotiation-error
branch
from
59f7deb to
18d3bd7
Compare
InteractiveTxConstructor contains the users contributed inputs. When an interactive tx sessions is aborted, the user will need to be notified with an event indicating which inputs and outputs were contributed. This allows them to re-use inputs that are no longer in use. This commit ensures the InteractiveTxConstructor is only consumed after all error checking. That way, in the case of a failure, we're able to produce an event from its input data.
jkczyz
force-pushed
the
2025-09-negotiation-error
branch
from
18d3bd7 to
0956efd
Compare
jkczyz
changed the title
NegotiationError for interactive-tx constructions
wpaulino
approved these changes
Oct 1, 2025
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Interactive transaction construction currently fails with an
AbortReason. However, in order to produceSpliceFailedevents in #4077, the contributed inputs and outputs need to be accessible. That is, they cannot be consumed if returning an error. This PR refactors interactive-tx construction code and uses to avoid consumingInteractiveTxConstructionuntil all error checking has completed.