[erskingardner]

Problem

A transport-nostr test ejected #3279 from the merge queue. It checks that spilled deliveries fence the cursor right after they are placed, but its spill store let the writer run freely. The writer runs on a runtime worker and the blocking pool, in parallel with the test body, so when the test thread was descheduled after placement, the writer had already settled both hand-offs and lowered the fence. Only the test suite is affected: placement raises the fence under the lock every cursor commit reads, and the writer lowers it only after the store returns.

Fix

The test now uses the gated spill store its sibling tests use. While the writer is held, it checks the fence and that a commit is refused. Then it opens the gate, waits for the fence to lift, and checks that a commit passes again, capped only by the queue.

Verification

• Local: cargo fmt --all; cargo clippy -p transport-nostr --all-targets --all-features --locked -- -D warnings; cargo nextest run -p transport-nostr --all-features (154 passed; the changed test takes about 17 ms)
• Reproduction: a temporary 50 ms stall of the test thread between placement and the fence check failed the old test in 20 of 20 runs, with the queue's panic. With the same stall, the new test passed 20 of 20.
• Determinism: cargo nextest run -p transport-nostr --features test-support --stress-count 2000 -E 'test(=tests::deliveries_placed_after_a_live_seal_spill_what_only_that_promotion_stopped_covering)', with 20 busy-loop processes loading the 14-core Mac (load average up to 46): 2000 of 2000 passed. Under the same load the old test also passed 500 of 500, because this Mac never descheduled the test thread at that point. That is why the stall was needed to reproduce it.
• Mutation: with the fence increment removed from placement, the new test fails at the fence assertion.
• End-to-end smoke: not run. The change is inside #[cfg(test)] mod tests, which no smoke build compiles.
• Review: Codex (gpt-6.1-sol) and Cursor (grok-4.7-high-fast) recommend merge at 695ebae

Fixes #3282

🤖 Generated with Claude Code

Summary by CodeRabbit

• Tests
  • Updated coverage for cursor caps while spill writes are pending and after they complete.

[coderabbitai]

Walkthrough

The live-seal spill test now uses a gated spill store. It checks cursor fencing while spill hand-offs are pending, then waits for settlement and checks that the queued delivery caps the cursor at live_floor + CURSOR_LOOKBACK.

Changes

Live-seal spill cursor fence

Layer / File(s)	Summary
Gate spill hand-offs and verify cursor cap crates/transport-nostr/src/tests.rs	The test holds spill hand-offs during the cursor-fence check. It then opens the gate, waits for both hand-offs to settle, and asserts that the queued delivery at live_floor caps the cursor at live_floor + CURSOR_LOOKBACK.

Estimated code review effort: 2 (Simple) | ~8 minutes

Severity of issue fixed: Low

Possibly related issues

• Remaining timing-dependent test waits #2412: This issue calls for replacing timing-dependent waits with observable readiness or contention evidence. The test gates the spill writer and checks the fence before and after settlement.

Possibly related PRs

• marmot-protocol/mdk#2950: Both changes test cursor fencing while spill hand-offs remain unresolved and after they settle.

Merge Risk: Minimal · up to 695eb

This change only makes a flaky test deterministic by holding the spill writer during the fence check. It does not change production behavior and no merge-blocking risk remains.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentat…	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly describes the main change: gating the spill writer so the live-seal spill test can check the cursor fence reliably. The issue reference is relevant and does not obscure the title.
Linked Issues check		Issue #3282 requires a deterministic fix for the race in deliveries_placed_after_a_live_seal_spill_what_only_that_promotion_stopped_covering. The test now uses gated_recording_spill_store(), check…
Out of Scope Changes check		The pull request changes only the named test in crates/transport-nostr/src/tests.rs. The gated store, fence assertions, and post-settlement cursor assertion directly test issue #3282. No unrelated p…

Full details: Linked Issues check

Explanation

Issue #3282 requires a deterministic fix for the race in deliveries_placed_after_a_live_seal_spill_what_only_that_promotion_stopped_covering. The test now uses gated_recording_spill_store(), checks the fence and refused commit while the writer is held, opens the gate, waits for settlement, and verifies the post-spill commit cap. The focused diff shows the required test change.

Full details: Out of Scope Changes check

Explanation

The pull request changes only the named test in crates/transport-nostr/src/tests.rs. The gated store, fence assertions, and post-settlement cursor assertion directly test issue #3282. No unrelated production or feature changes are present in the reviewed diff.

Full details: Docstring Coverage

Explanation

Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentation-only edits and deletions within surviving functions are included; unchanged diff context and fully deleted functions are excluded. Analyzed 1 functions across 1 files.

Resolution

Write docstrings for the functions missing them to satisfy the coverage threshold.

Finishing Touches

Generate docstrings

• Commit to this branch
• Create a new PR

Generate unit tests (beta)

• Commit to this branch
• Create a new PR

• Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

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Failed pre-merge checks:
- Docstring Coverage:
Write docstrings for the functions missing them to satisfy the coverage
threshold.

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Commits

Reviewing files that changed from the base of the PR and between 8cd2955 and 695ebae.

Files selected for processing: 1

• crates/transport-nostr/src/tests.rs

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