fix(tool): surface MessagePool service task errors in api_cmd test ctx

[0xDevNinja]

Summary of changes

Changes introduced in this pull request:

• Own the JoinSet in test_snapshot::ctx and generate_test_snapshot::ctx instead of passing &mut JoinSet::new() into MessagePool::new. The inline temporary was dropped on return, aborting every spawned mpool service task and silently swallowing any errors they emitted pre-cancellation.
• Move the owned JoinSet into a detached tokio::spawn(drain_mpool_services(...)) that drains it with the canonical while let Some(result) = services.join_next().await loop from daemon/mod.rs::propagate_error, logging errors and non-cancel panics via tracing::warn!.
• Add a shared drain_mpool_services helper in test_snapshot.rs (visibility pub(super)) and call it from both ctx() sites.

Detaching (vs. awaiting inline) is deliberate: the mpool services are long-lived, so an inline while let Some(...) would never return — that is precisely what caused codecov CI to time out and led to the earlier attempt being reverted from #6493. A detached drainer surfaces errors without blocking the caller.

Reference issue to close (if applicable)

Closes #6505

Other information and links

• Canonical drain pattern: src/daemon/mod.rs:842-851 (propagate_error).
• MessagePool::new signature confirmed at src/message_pool/msgpool/msg_pool.rs:~721 — takes services: &mut JoinSet<anyhow::Result<()>>, which matches the generic used here.
• Prior related PR (different file, same pattern): test: unit test for start_rpc #6493.
• No CHANGELOG.md entry — this is an internal test utility change and is not user-facing per the changelog guide at the top of that file.
• No new test: the fix is observability-only (previously-silent warnings now surface via tracing); asserting on log output would be flaky. Existing rpc_regression_tests_print_uncovered passes locally; the heavier regression harness defers to CI.

Change checklist

• I have performed a self-review of my own code,
• I have made corresponding changes to the documentation. All new code adheres to the team's documentation standards,
• I have added tests that prove my fix is effective or that my feature works (if possible),
• I have made sure the CHANGELOG is up-to-date. All user-facing changes should be reflected in this document.

Outside contributions

• I have read and agree to the CONTRIBUTING document.
• I have read and agree to the AI Policy document. I understand that failure to comply with the guidelines will lead to rejection of the pull request.

AI Usage Disclosure

This PR was prepared with assistance from Claude Code (Anthropic). Extent:

• Issue analysis, implementation, self-review, and PR drafting were AI-assisted.
• All changes were compiled and tested locally by me before pushing — cargo fmt --all -- --check, cargo clippy --all-targets --no-deps -- -D warnings (with FOREST_F3_SIDECAR_FFI_BUILD_OPT_OUT=1), cargo check --lib --tests, and cargo test --lib rpc_regression_tests_print_uncovered (1/1 pass) all green.
• I have reviewed every diff line and take full responsibility for correctness.

Summary by CodeRabbit

• Tests
  • Improved message pool service task tracking and error logging during snapshot validation to prevent silent task failures and ensure reliable test execution.

[CLAassistant]

All committers have signed the CLA.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: be91ec8e-fed5-41d0-b0ff-9c6b692dfdb1

📥 Commits

Reviewing files that changed from the base of the PR and between 65c39a0 and e005443.

📒 Files selected for processing (2)

• src/tool/subcommands/api_cmd/generate_test_snapshot.rs
• src/tool/subcommands/api_cmd/test_snapshot.rs

---

Walkthrough

These changes ensure that background JoinSet task results in test utility functions are properly handled instead of being silently dropped. A new drain_mpool_services function encapsulates the draining logic, logging warnings for task execution errors and panics while maintaining cancellation tolerance.

Changes

Cohort / File(s)	Summary
JoinSet Error Handling in Test Utilities src/tool/subcommands/api_cmd/test_snapshot.rs, src/tool/subcommands/api_cmd/generate_test_snapshot.rs	Added proper error handling for JoinSet task results instead of silent drops. Introduced new pub(super) async fn drain_mpool_services() that iterates through JoinSet results, logging warnings for task failures and panics while ignoring cancellations. Both files now create a shared JoinSet passed to MessagePool::new and spawn a background task to drain it.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The PR title clearly identifies the main change: fixing MessagePool service task error surfacing in api_cmd test utilities by properly handling JoinSet results.
Linked Issues check	✅ Passed	The PR fully addresses issue #6505 requirements: adopts the canonical while let Some(res) pattern in both test files, creates drain_mpool_services helper for centralized error handling, and maintains detached spawning to avoid codecov timeouts.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to issue #6505: modifications limited to the two specified test files to fix JoinSet error handling, with no unrelated alterations.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

✨ Simplify code

• Create PR with simplified code

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}