[kixelated]

Problem

Recover::wants in rs/moq-net/src/model/resume.rs loops while poll_changed is ready. poll_changed maps a closed route state (kio Ref error) to Ready. When the routes close without setting end or concluded, and a reader is stalled mid-group on the same copy, the loop never exits: one worker spins at 100% CPU inside a single poll, from GroupServe::poll_serve through group::Consumer::poll_resumed into wants. A runtime waiting on that task never shuts down. It came in with #6224.

Approach

Treat route.is_closed() like concluded in the loop's exit check, as Recover::poll and end() already do. A closed route then reads like a conclusion: the reader parks on the copy it is reading and finishes the group from it.

Regression test a_stalled_group_parks_when_the_routes_close: a reader stalled mid-group, routes dropped, then the read is pending, and the group finishes from the original copy. Without the fix, kio's sim poll budget panics with "Ready poll limit exceeded" at poll_changed.

Impact

• No public API or wire change.

Alternatives

• Make poll_changed return Pending on a closed state: it would then never wake for a closed route, and poll's own closed check relies on it waking.

Follow-ups

• None.

just ci passes on 558d633.

(Written by Opus 5.5)

🤖 Generated with Claude Code

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Codex Review Summary

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-24T21:43:05.508288Z	558d633	PR opened

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Recent review info

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Commits

Reviewing files that changed from the base of the PR and between 8ee7728 and 558d633.

Files selected for processing: 1

• rs/moq-net/src/model/resume.rs

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Walkthrough

Recover::wants now treats a closed route as a completed wait condition, alongside an explicit end or conclusion. A new async regression test checks that a stalled group remains readable from its existing producer after routes are dropped, then reads the remaining frame and end.

Priority: Normal

Merge Risk: Minimal · up to 558d6

The change addresses the stalled closed-route shutdown issue without identifying a remaining merge-blocking risk.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 66.67% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 3 functions across 1 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
Title check		The title names the main change: a stalled group read spinning on closed routes is fixed in the net crate. It matches the raw summary, which says Recover::wants now treats a closed route as a complete…
Description check		The description covers the problem, the approach, a regression test, the impact, and alternatives. It names the same file, function, and test as the raw summary. It is directly related to the changese…
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

Full details: Title check

Explanation

The title names the main change: a stalled group read spinning on closed routes is fixed in the net crate. It matches the raw summary, which says Recover::wants now treats a closed route as a completed wait condition, and the PR objectives, which describe exiting the polling loop when route.is_closed(). The title is specific and follows the conventional commit style.

Full details: Description check

Explanation

The description covers the problem, the approach, a regression test, the impact, and alternatives. It names the same file, function, and test as the raw summary. It is directly related to the changeset.

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