rust-lightning Introduce interactive signing state flags for funded states.

This PR includes some deferred follow-ups extracted from #3423 and introduces new state flags to track interactive signing along with persistence of the minimum information needed from a signing session to reconstruct it.

A top-level state flag was avoided so that this work is compatible with splicing as well as V2 channel establishment (dual-funding).

Mar 03 '25 18:03 dunxen

👋 Thanks for assigning @jkczyz as a reviewer! I'll wait for their review and will help manage the review process. Once they submit their review, I'll check if a second reviewer would be helpful.

Mar 03 '25 18:03 ldk-reviews-bot

Did you want to include test coverage for restarts here?

Not yet. Tracked in #3636. Will need to be able to contribute inputs first to test a useful order of message exchange + restart.

Mar 04 '25 15:03 dunxen

Codecov Report

Attention: Patch coverage is 64.55026% with 67 lines in your changes missing coverage. Please review.

Project coverage is 90.01%. Comparing base (89f5217) to head (fb00cb6). Report is 19 commits behind head on main.

Files with missing lines	Patch %	Lines
lightning/src/ln/channel.rs	59.55%	49 Missing and 6 partials :warning:
lightning/src/ln/interactivetxs.rs	46.66%	8 Missing :warning:
lightning/src/ln/channelmanager.rs	90.90%	1 Missing and 1 partial :warning:
lightning/src/ln/dual_funding_tests.rs	87.50%	1 Missing :warning:
lightning/src/util/ser.rs	85.71%	0 Missing and 1 partial :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3637      +/-   ##
==========================================
+ Coverage   89.37%   90.01%   +0.63%     
==========================================
  Files         157      157              
  Lines      124095   129376    +5281     
  Branches   124095   129376    +5281     
==========================================
+ Hits       110915   116452    +5537     
+ Misses      10469    10187     -282     
- Partials     2711     2737      +26

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Mar 05 '25 10:03 codecov[bot]

@dunxen re-request when this is ready for review again, feel free to squash as well

Mar 05 '25 21:03 wpaulino

🔔 1st Reminder

Hey @TheBlueMatt @jkczyz @wpaulino! This PR has been waiting for your review. Please take a look when you have a chance. If you're unable to review, please let us know so we can find another reviewer.

Mar 06 '25 12:03 ldk-reviews-bot

Taking myself off since @wpaulino and @jkczyz are on this one. Aside from my first comment I don't have any more high-level feedback.

Mar 06 '25 23:03 TheBlueMatt

🔔 1st Reminder

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Mar 15 '25 14:03 ldk-reviews-bot

🔔 2nd Reminder

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Mar 17 '25 14:03 ldk-reviews-bot

Just pushed the change for full persistence of InteractiveTxConstructor. Still addressing other feedback.

Mar 19 '25 10:03 dunxen

@dunxen let us know when this is ready for another round

Mar 24 '25 17:03 wpaulino

@wpaulino, @jkczyz, sorry for the delay. This is ready for another round.

Mar 27 '25 12:03 dunxen

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Mar 29 '25 12:03 ldk-reviews-bot

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Mar 31 '25 12:03 ldk-reviews-bot

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Apr 05 '25 11:04 ldk-reviews-bot

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Apr 05 '25 11:04 ldk-reviews-bot

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Apr 07 '25 11:04 ldk-reviews-bot

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Apr 07 '25 11:04 ldk-reviews-bot

Looks like there's some breakages in the full_stack fuzz test.

Thanks, will address those. Honestly haven't paid much attention as fuzz had been broken for a while on main I believe.

Apr 09 '25 08:04 dunxen

Hmm... when possible please avoid rebasing unless necessary. Otherwise, it makes it difficult to view new changes related to the PR. If needed, doing two separate pushes would be ideal.

Apr 09 '25 13:04 jkczyz

Thanks, will address those. Honestly haven't paid much attention as fuzz had been broken for a while on main I believe.

Locally, it still should work. CI has just been timing out (unfortunately) but will catch actual failures, AFAICT.

Apr 09 '25 13:04 jkczyz

Locally, it still should work. CI has just been timing out (unfortunately) but will catch actual failures, AFAICT.

Oh yeah I see this was just related to the new bool in config.

Apr 09 '25 13:04 dunxen

Hmm... when possible please avoid rebasing unless necessary.

Sorry, bad habit I do sometimes. I'll keep it in mind again.

Apr 09 '25 13:04 dunxen

Changes:

git diff-tree -U1 4f6192f 21a25fb3f
diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs
index b43e47e68..a60f3f293 100644
--- a/lightning/src/ln/channel.rs
+++ b/lightning/src/ln/channel.rs
@@ -5849,4 +5849,3 @@ impl<SP: Deref> FundedChannel<SP> where

-               let need_channel_ready = self.check_get_channel_ready(0, logger).is_some();
-               self.monitor_updating_paused(false, false, need_channel_ready, Vec::new(), Vec::new(), Vec::new());
+               self.monitor_updating_paused(false, false, false, Vec::new(), Vec::new(), Vec::new());

@@ -6496,3 +6495,3 @@ impl<SP: Deref> FundedChannel<SP> where
                if !matches!(self.context.channel_state, ChannelState::FundingNegotiated(flags) if flags.is_interactive_signing()) {
-                       return Err(ChannelError::close("Received tx_signatures in strange state!".to_owned()));
+                       return Err(ChannelError::Ignore("Ignoring tx_signatures received outside of interactive signing".to_owned()));
                }

Apr 11 '25 06:04 dunxen

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Apr 16 '25 10:04 ldk-reviews-bot

Changes:

git diff-tree -U1 7d19a76 21d3c78
diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index ecec47387..93dd16e7d 100644
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -11989,3 +11989,3 @@ where
        fn handle_open_channel_v2(&self, counterparty_node_id: PublicKey, msg: &msgs::OpenChannelV2) {
-               if !self.node_features().supports_dual_fund() {
+               if !self.init_features().supports_dual_fund() {
                        let _: Result<(), _> = handle_error!(self, Err(MsgHandleErrInternal::send_err_msg_no_close(

Apr 16 '25 13:04 dunxen

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Apr 19 '25 00:04 ldk-reviews-bot

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Apr 28 '25 00:04 ldk-reviews-bot