test(kernel): dump daemon-side state when a dispatch never arrives (#174)

[kjgbot]

Replaces #176, which GitHub auto-closed when #175 merged and its base branch was deleted. Same change, rebuilt directly on main now that both #175 and #177 have landed.

Why

#174 produced four occurrences and, between them, four test names. Nothing else. The state that would explain it was all daemon-side and none of it survived: wait_with_output() is never reached, so the child's output is dropped in the unwind, and the run's journal was never read.

What it does

On a missing dispatch the test attempts to terminate the resumed child and reaps it, then reports its stdout, stderr, and the run's journal entries with seq, type and step.

The child may be stalled or may have already exited, and those are indistinguishable from the test's side — which is exactly why the dump matters. #174 turned out to be the second: the resume died instantly with run_not_found while the test waited 60s on it.

The journal is the important half. The question a missing dispatch raises is did the daemon resume and stall, or never resume at all? Nothing else answers it. The listing covers the current segment — every entry these non-compacting crash tests produce, though not every entry under compaction.

This is what found #174's root cause, fixed in #177.

Evidence

Forcing the read ceiling to 1ms:

before-first: no step.dispatch after resume: timed out after 1ms waiting for a
protocol frame; the daemon sent nothing (see #174)
--- resume child ---
stdout (0 bytes):

stderr (0 bytes):

--- journal (1 entries) ---
  seq=1 type=RunSpawned step=None

sha256 19f3431a → 361572ef → restored 19f3431a, no 1ms literal left in the tree.

Measured at this head: workspace 152 passed, 0 failed, no warnings; crash_resume 34 passed in 37.98s.

Signoff: local 3-lens preswarm at this head — maintainability / history / structure all REVIEW_PASSED. The history lens caught that an earlier message asserted the child "is still running" while also describing a child that had already exited; that contradiction is corrected in both the message and the code comment.

🤖 Generated with Claude Code

https://claude.ai/code/session_01FtQSAcGDta5VH9xiZFT4sR

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📥 Commits

Reviewing files that changed from the base of the PR and between 696d3e3 and e6a557d.

📒 Files selected for processing (3)

• kernel/relayflowd/tests/crash_resume/agent.rs
• kernel/relayflowd/tests/crash_resume/llm.rs
• kernel/relayflowd/tests/crash_resume/support.rs

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📝 Walkthrough

Walkthrough

Crash-resume tests now capture resume dispatch errors instead of unwrapping them. A shared helper terminates the resume process, collects stdout and stderr, and reports current journal state in labeled panic diagnostics.

Changes

Crash Resume Diagnostics

Layer / File(s)	Summary
Resume diagnostic collection kernel/relayflowd/tests/crash_resume/support.rs	Added describe_stalled_resume to reap the resume process, capture both output streams, and report current journal entries or an absent-journal status.
Dispatch failure reporting kernel/relayflowd/tests/crash_resume/agent.rs, kernel/relayflowd/tests/crash_resume/llm.rs	Resume dispatch now handles protocol errors explicitly and includes stalled-resume diagnostics in panic output. Successful dispatch remains unchanged.

Estimated code review effort: 2 (Simple) | ~10 minutes

Poem

A rabbit checks the resume trail,
And gathers logs when steps derail.
The journal speaks, the streams reply,
While labeled panics point the why.
Crash tests hop onward, ears held high.

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