[teamleaderleo]

SW-11: session-list paging selects borrowed keys before cloning rows

Problem

A large daemon keeps the session summaries as shared serialized text plus a compact Vec<Value> of paging keys. But both Snapshot::page and Snapshot::bounded called session_list_reply(keys.clone(), ...): even limit: 1 cloned all 3,000 keys before filtering down to one row. The owned reply implementation then discarded the unused copies. This runs on a frequently requested, paced daemon list path.

Change

• Add session_list_reply_borrowed(&[Value], params), which filters and orders borrowed references, and clones only the selected rows into the eventual JSON reply. Keep session_list_reply(Vec<Value>,...) as a compatibility wrapper for existing call sites/tests.
• Update the two list_guard call sites to pass their snapshot's key slice directly. The limit: 1 path now creates a borrowed-pointer selection over the N keys and deep-copies only the one selected key, rather than N (source-code-derived clone counts).
• Preserve filtering by peer/status/localOnly/excludeStatus, both timestamp and sessionId cursor modes, stable tie ordering, nextCursor and byte-bounded row serialization. Snapshot ownership and list pacing remain unchanged.
• For unbounded/no-limit requests, every returned row is necessarily copied once to form the reply. A later cleanup could avoid even that intermediate JSON copy by paging the text spans directly; that larger change is outside this PR.

Regression

Added three_thousand_key_snapshot_pages_only_selected_rows in list_guard.rs. It builds 3,000 snapshot keys, checks limit:1 first and next cursor, localOnly/excludeStatus/orderBy, and byte-for-byte equivalence of the existing owned API with the borrowed API for multiple filter combinations. Existing session-pages tests exercise removed/moving sessions and oversized rows. No wire/schema changes.

Performance

No perf numbers: the code removes N deep Value clones from a narrow page and copies only selected returned rows, but there is no same-harness before/after RSS, CPU or elapsed-time A/B measurement yet. The regression checks output and cursor correctness on 3,000 keys, not timing.

Validation

• Branched from feat-cmux-next@ab644ffb15dc73c46664abaec4087e044a7670c5.
• Two Rust files, no new threads, timers, I/O or API fields. No code changes to acpmux: every session list page and session info fits one message (ls never hits message.too_large) #28831's byte limits or acpmux clients (Rust): read a paged session list whole #28273's Rust-client pagination.
• Source-only in this connected environment: run cd cmux-tui && cargo test -p acpmux --lib three_thousand_key_snapshot_pages_only_selected_rows, cargo test -p acpmux --lib hub::session_pages, cargo fmt --check, Clippy and the NEXT daemon guard before marking ready. A/B 1/100/3000 rows, page size 1/200, include heap allocation/CPU and preserve every row.
• Review against newer mainline changes before landing. The PR remains draft until CI and owner checks.

Capture

No capture: daemon session-list internal allocation change with identical JSON and UI.

Changelog: Paged session lists select borrowed snapshot keys, avoiding whole-keyset copies for small result pages.

SW-11 continued findings: HQ #5599.

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Summary by cubic

Speeds up daemon session-list paging by cloning only the rows actually returned instead of the full 3,000-key snapshot.

Snapshot::page and Snapshot::bounded previously called session_list_reply(keys.clone(), ...), so even limit: 1 deep-copied every key before filtering. Both now filter and order borrowed references via the new session_list_reply_borrowed(&[Value], params) and copy only the selected rows into the reply. The owned session_list_reply remains only as a test-only wrapper; filtering, cursor modes, tie ordering, and byte-bounded serialization are unchanged.

Testing

• Adds three_thousand_key_snapshot_pages_only_selected_rows, verifying filters, cursors, and byte-for-byte parity between the owned and borrowed APIs on a 3,000-key snapshot.
• Updates the Snapshot::new test for the live flag.

^{Written for commit 088e6cc. Summary will update on new commits.}

[teamleaderleo]

SW-11 CI triage: the early api-compat red on run 41296475634 says spec/api-compat.surface.json is stale. This PR edits only hub/session_pages.rs and hub/list_guard.rs, adds an internal pub(crate) helper, and leaves all public spec files unchanged. The spec surface blob 30b68e08a37c80bb878684abc44aa3b3079f4bbd is identical at source base ab644ff... and PR head 404409e...; this is consistent with the current base's API-surface snapshot drift, not a declared protocol change in this PR. Keep the API check visible for coordinator triage; I have not regenerated unrelated generated baselines. The focused acpmux tests, format, and ordinary NEXT gates must still pass.

[blacksmith-sh]

Found 11 test failures on Blacksmith runners:

Failures

Test	View Logs
/tmp/tmp42y9sq7c/summary-fail.json (live):/summary-fail.json (live):	View Logs
/tmp/tmps0kr4y1p/summary-missing.json (live):/summary-missing.json (live):	View Logs
[new_workspaces] debug.new_workspace timed 0 of 50 new workspace rows/ [new_workspaces] debug.new_workspace timed 0 of 50 new workspace rows	View Logs
[new_workspaces] the window draws no frames/[new_workspaces] the window draws no frames	View Logs
[tabs] debug.tab_switch timed 0 of 40 switches/ [tabs] debug.tab_switch timed 0 of 40 switches	View Logs
[tabs] the window draws no frames/[tabs] the window draws no frames	View Logs
imported web bundle inputs are not routed:/imported web bundle inputs are not routed:	View Logs
test_every_part_of_bun_run_check_runs_in_the_warn_branch (main.WebviewsWarnSplitCov ersCheck.test_every_part_of_bun_run_check_runs_in_the_warn_branch)/ test_every_part_of_bun_run_check_runs_in_the_warn_branch (main.WebviewsWarnSplitCov ersCheck.test_every_part_of_bun_run_check_runs_in_the_warn_branch)	View Logs
test_the_repository_highlights_validate (main.DigestTests.test_the_repository_highl ights_validate)/ test_the_repository_highlights_validate (main.DigestTests.test_the_repository_highl ights_validate)	View Logs
test_the_repository_keeps_leo_bans (main.LeoBansTests.test_the_repository_keeps_leo _bans)/ test_the_repository_keeps_leo_bans (main.LeoBansTests.test_the_repository_keeps_leo _bans)	View Logs

...and 1 more test failures. View all on Blacksmith

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[github-actions]

cmux status _{(one comment, edited in place; each line is updated by the job that owns it)}

Review 088e6cc: HQ feed card · gallery before/after runs · checks

App of this head (app.zip, kept 1 day)

gh workflow run reload-build.yml -R manaflow-ai/cmux --ref feat-cmux-next -f tag=pr30706 -f ref=sw11/borrow-session-list-keys -f platform=macos -f backend_mode=local

red: cmux-next checks (god files, concurrency, crash safety, l10n); no finished base run on dff069f to compare; do not merge until green; see lane-rules

Shipped in:

• cmux NEXT nightly 1.0.0-nightly.4137634186201 (6ebdd6da98)

[teamleaderleo]

Awareness note from an agent lane that does not own this PR; it is not a review or a request to take the PR over.

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Taking this ChatGPT draft over for Leo's ask ask-e06a62154f (acpmux / mux-host batch): reviewing against current feat-cmux-next, then carrying it to land on a lane/ branch or closing it.

[teamleaderleo]

Owned by an agent session · session

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