fuzz: add force-close support to chanmon_consistency#4381
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joostjager wants to merge 16 commits intolightningdevkit:mainfrom
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fuzz: add force-close support to chanmon_consistency#4381joostjager wants to merge 16 commits intolightningdevkit:mainfrom
joostjager wants to merge 16 commits intolightningdevkit:mainfrom
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👋 I see @wpaulino was un-assigned. |
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #4381 +/- ##
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- Coverage 86.12% 86.10% -0.03%
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Files 157 157
Lines 108824 108851 +27
Branches 108824 108851 +27
==========================================
Hits 93727 93727
- Misses 12480 12505 +25
- Partials 2617 2619 +2
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wpaulino
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Feb 10, 2026
| }, | ||
| events::Event::SplicePending { .. } => {}, | ||
| events::Event::SpliceFailed { .. } => {}, | ||
| events::Event::ChannelClosed { .. } => {}, |
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We should probably open a new channel to replace the force closed one?
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| // Only check for no broadcasts if no force-closes happened. | ||
| if !fc_ab && !fc_bc { | ||
| assert!(broadcast.txn_broadcasted.borrow().is_empty()); |
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I have some changes that will be going up soon that rework this, you may want to wait until then. Each node will have its own broadcaster, and there's also a concept of a "chain" now so we can mine transactions.
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Changes were very useful! The per-node broadcasters (broadcast_a/broadcast_b/broadcast_c) are used to selectively drain and confirm each node's force-close commitment txs, and the ChainState abstraction is used to confirm broadcast transactions and advance block height past HTLC timelocks during settlement.
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Needs rebase. Is this stalled waiting on fixes that were discovered by the fuzzer? |
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I was working on my local branch only for a while. Just pushed what I have. But indeed, the mixed mode failure is also showing up in different ways with fc fuzzing. |
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Rebased onto #4571, because compile times became unworkable with the many macros. |
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Collect local notes and fuzz inputs used while investigating the force-close chanmon_consistency work. These files are marked dropme so they can aid review and reduction without becoming part of the final patch set.
Remember claim outpoints after their spending transactions have reached the anti-reorg delay, even after normal claim tracking is cleaned up. This prevents later claims for newly learned preimages from attempting to spend outputs that were already irrevocably claimed on chain.
Allow fuzz builds to use cheaper ECDSA signatures and skip assertions that rely on production signature sizes. The fuzz signer intentionally trades realistic DER lengths for speed, so weight lower-bound checks must not assume low-R signatures there.
Replace the test persister with harness-owned monitor persistence that tracks completed and in-progress updates. This lets restarts select persisted or pending monitor snapshots and exercise reload behavior across asynchronous monitor update states.
Seed each harness wallet with confirmed coinbase outputs before building channels. The modeled chain now includes the wallet funding, so later chain checks can require transactions to spend existing outputs.
Track confirmed UTXOs in the harness chain state and require transactions to spend outputs that exist and remain unspent. Also reject absolute-height timelocks before they mature, while preserving the obscured commitment number encoding used by commitment transactions.
Notify channel monitors about confirmed transactions and best-block updates while harness nodes catch up to the modeled chain. When advancing across empty blocks, jump directly to the next block that contains transactions while still reporting the intervening best block.
Teach the harness to deliver additional control and announcement messages emitted during reconnects and timer-driven state changes. This keeps delayed message handling from panicking on valid events that can be produced by the channel manager.
Stop treating every channel close or broadcast transaction as an immediate invariant failure. Later commits add explicit force-close coverage, so the baseline harness must allow channels and broadcaster queues to reflect closure progress.
Return the transactions confirmed from the pending pool and apply their effects to the harness wallets. This keeps wallet UTXO state aligned with the fake chain when splice or other pending transactions are mined by fuzz input.
Map the primary signer-unblock opcodes so nodes 0, 1, and 2 each get distinct controls for counterparty commitment signing, per-commitment points, and commitment secret release. Make node B's primary signer-unblock controls retry all pending channels once an operation is available, while keeping the older channel-specific release-secret controls for now. This avoids duplicated node coverage and makes the byte controls easier to reason about in reduced test cases.
Make event processing robust to splice, close, spendable-output, and bump-transaction events that can arise during on-chain cleanup. Splice pending handling now finds the matching broadcast transaction by txid instead of assuming queue order.
Add cleanup helpers and fuzz opcodes for monitor bump events, broadcast confirmation, careful chain advancement, and node resyncs. The all-events loop now advances messages, node events, monitor events, pending transactions, and broadcasts until the harness quiesces.
Before final assertions, catch raw monitors up to node height and drive timer ticks plus block advancement until pending work clears. The final liveness probe now uses each channel's advertised sendable range instead of a fixed amount that may be outside its limits.
Track payment hashes, paths, claims, sender outcomes, and closed channels so settle-all can distinguish unresolved work from valid force-close outcomes. This lets the harness accept sender failure for claimed dust paths while still asserting that observable payment lifecycles complete.
Add explicit force-close fuzz actions for the A-B and B-C channels. Enable holder commitment and holder HTLC signing together so on-chain cleanup retries do not split the paired monitor-side signer operations. The all-node holder-signing byte remains as a compatibility alias for existing fuzz inputs. The harness records dust HTLC paths before closing so later payment resolution checks can account for claims blocked by dust outputs.
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Add force-close coverage to the
chanmon_consistencyfuzzer. Previously, the fuzzer only exercised cooperative channel flows. This PR enables the fuzzer to force-close channels and verify that on-chain resolution, HTLC timeouts, and payment preimage propagation all work correctly under channel monitor consistencyconstraints.