[lawrencecchen]

Base-red fix (fix forward). The Rust panic ratchet is red on feat-cmux-next since 72dc85d (#30361, Cloud repository discovery). The tip watcher's --arg panic step failed at 4cd800a (job 63b147f0938fdb56741e7c83) and again at b9b4ac5 (job b2e7ab23614482433a9e00b5). It passed at 4b15acd (job 919042f7eb84849e08597ca8).

crate	clippy::indexing_slicing at the tip	baseline
acpmux	694	686
cmux-host	1	0
cmux-tui	836	831
cmux-tui-core	880	853

The watcher reported only the first crate (acpmux, +8). Four crates are red. All of the new hits come from #30361. The other first-parent commits in 4b15acdb7ae8..4cd800a309c2 (#30197, #30157, #28937, #30362, #29826 and others) add no index or slice in production code.

What changed

Each serde_json index read that #30361 added in production code is now a get / pointer read. The one IndexMut is now get_mut. The slice command[..2] is now command.get(..2). The baseline is not raised.

file	hits	now
acpmux/src/cloud_repo_mcp.rs	17	get(..).and_then(Value::as_str), pointer("/error/code"), and get_mut("error") in enrich_retry
cmux-host/src/cloud/github_repos.rs	3	pointer("/error/code"), get("provider"), get("_tag")
cmux-tui/src/cli/cloud_repo.rs	4	get("id"), get("ok"), get("error_code"), get("error")
cmux-tui/src/cli.rs	1	command.get(..2).is_some_and(..) (the old code checked len() >= 2 first)
cmux-tui-core/src/cloud_repos/{engine,local,runtime,store}.rs	rest	get / pointer reads; store.rs gets two small readers, chat_repos and recent_repos

There is no change in behavior. A missing key read through get gives the same result as the Null that indexing returned:

• v["k"] == "x" becomes as_str() == Some("x").
• v["ok"] != true becomes as_bool() != Some(true).
• existing["ref"] != json!(reference) keeps Null for a missing key.
• from_value(doc["local"].clone()) becomes from_value(get(..).cloned().unwrap_or_default()), which is still Null, so a missing list still fails the same way.
• enrich_retry used to write through &mut result["error"] only when result["error"] was an object, so the get_mut form takes the same branch.

Update after the merge of feat-cmux-next (1dfc4dd)

The merge had conflicts in cloud_repo_mcp.rs, engine.rs and runtime.rs with #30528 (let-chains) and #30382 (seed.unknown_job). The resolution keeps their logic and the get reads. At the merge head 9d4a172 the ratchet was still red (job 1764d0cc925c9f12951dc4c3) on two rows that later base commits added. Both are fixed here too, because base reds go in one PR:

• acpmux indexing_slicing 689 > 686: Sidebar hover preview: count and name each agent's running subagents; History drops inbox notices #30439 added summary["turn"] in hub/views.rs and self.running[at] (twice) in subagents.rs. They are now get("turn") and get_mut(at). at is a position in the same Vec, found just before with no change between.
• cmux-tui string_slice 83 > 82: link: plan a git-seed-v1 seed of a GitHub working copy #30464 added &text[prefix.len()..] in link/seed/github.rs. It is now split_at_checked, which gives None in the same cases as the old get(..n).

Testing

run	ref	result
panic ratchet (--arg panic)	tip 4cd800a	RED: the four rows above, job 63b147f0938fdb56741e7c83
panic ratchet (--arg panic)	first head 8b701f4	pass (exit 0, no RED row, indexing_slicing at or under the baseline in all four crates), job 0b990c6938c0c3ba18439332. The warn-tier rows (arithmetic, casts) are the same as on the tip.
test cloud_repo (acpmux cloud_repo_mcp, cmux-tui-core cloud_repos, cmux-tui cli::cloud_repo and cloud_repo_tools)	8b701f4	37 of 37 pass, job 6083001dc37f62bd46fd723c
test github_repos (cmux-host)	8b701f4	9 of 9 pass, job cf655a5395608395acddeb21
panic ratchet (--arg panic)	merge head 9d4a172	RED: acpmux 689 > 686 and cmux-tui string_slice 83 > 82, from #30439 and #30464, job 1764d0cc925c9f12951dc4c3
panic ratchet (--arg panic)	head f9a0611	pass (no RED row), job 1f0e6bb20a1631d3f73a8b30
test subagents	f9a0611	51 of 51 pass, job 2d550515957dbd10a47c1254
test seed	f9a0611	79 of 79 pass, job 9fac88983e527560cdbb0f29
test cloud_repo	f9a0611	37 of 37 pass, job 5d73878f27ac96fcd368f66b

• Review (subagent, correctness first): SHIP at 8b701f4, at 9d4a172 (the merge) and at f9a0611 (the current head). It checked every rewrite against serde_json semantics and the enrich_retry borrow and found no blocking issue.

Observed / Not run

Observed: all the runs above (fleet Linux, Blacksmith overflow), prepush-gate.py (no new violations), and rustfmt 1.95 on the changed files.
Not run: macOS builds, because this PR has no Swift change. I did not run a macOS clippy, because the panic ratchet runs on Linux. #30555 (cloud_repo.rs validate is_none_or) overlaps 4 let-chain sites; whichever lands second merges the other.

Changelog

none

[cubic-dev-ai]

No issues found across 8 files

_{View guided diff | Turn on auto-fix | Re-trigger cubic}

[github-actions]

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

Review f9a0611: 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=pr30478 -f ref=fix/base-red-panic-acpmux-30361 -f platform=macos -f backend_mode=local

Shipped in:

• cmux NEXT nightly 1.0.0-nightly.4130052256501 (28aa638015)

[lawrencecchen]

Review (subagent, correctness first): SHIP at f9a0611

The reviewer checked the 3 new changes by reading:

• views.rs: summary is an owned Value, so get is serde_json's Value::get.
• subagents.rs: at comes from position on the same Vec with no change between, so get_mut is always Some.
• github_repos: split_at_checked gives None in the same cases as get(..n).

The merge resolutions keep #30528's let-chains and #30382's seed.unknown_job. Scope is 11 files over 1dfc4dd. It found no issue at any severity. Fleet at this head: ratchet green (1f0e6bb20a1631d3f73a8b30), and tests subagents 51/51, seed 79/79 and cloud_repo 37/37.

[lawrencecchen]

Review (subagent, correctness first): SHIP at 8b701f4

The reviewer read every rewrite against serde_json semantics. A missing key read through get / pointer gives the same result as the Null from indexing. enrich_retry with get_mut takes the same branch as before and passes the borrow check. The record closure stays Fn. It found no blocking issue. Fleet: ratchet green (job 0b990c6938c0c3ba18439332), cloud_repo tests 37/37 (6083001dc37f62bd46fd723c), github_repos tests 9/9 (cf655a5395608395acddeb21).

[blacksmith-sh]

Found 13 test failures on Blacksmith runners:

Failures

Test	View Logs
/tmp/tmp4ahbwwwy/summary-missing.json (live):/summary-missing.json (live):	View Logs
/tmp/tmpgzgfswln/summary-fail.json (live):/summary-fail.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
main.DeveloperIdAppTests.test_download_prints_the_active_profile_only/ test_download_prints_the_active_profile_only	View Logs
stubs: /System/Library/Frameworks/Security.framework/Versions/A/Security has no stub/ Security has no stub	View Logs
stubs: CoreFoundation.tbd: install-name /System/Library/Frameworks/ CoreFoundation.framework/Versions/A/CoreFoundation, missing 1: ['_CFRetain']/ CoreFoundation, missing 1: ['_CFRetain']	View Logs
stubs: CoreFoundation.tbd: install-name /System/Library/Frameworks/ CoreFoundation.framework/Versions/A/CoreFoundation, missing 1: ['_log2']/ CoreFoundation, missing 1: ['_log2']	View Logs

...and 3 more test failures. View all on Blacksmith

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