[teamleaderleo]

Leo, 2026-10-31: "whenever i start a chat it should be able to send me to cloud autommatically keep launching/downloading new dev builds and such".

Follow-up to #30258 (and item 3 of #30373). A fleet capture of a DEV build that includes #30258 still failed the first Cloud send with "cloud-chats runs an older cmux that can't take this chat yet", because the update had no build to install:

• A DEV app bundles cmux-tui built from its own source tree (mode=tree in cmux-tui.version). CI never publishes the DEV app's own commit, so files.cmux.com/cmux-tui/<commit>/manifest.json was a 404. CI publishes the tree instead, under tree/<key>/, from whichever commit first built it.
• So cmux link machine update answered machine_update_unavailable.

Change (Rust, cmux-remote and cmux link machine update)

• pinned_linux_payload: when the build's own commit manifest is missing, read key= from the tree-mode cmux-tui.version beside the binary, then:

  • fetch tree/<key>/source.json;
  • check that the key matches and the publishing commit is a 40-hex commit;
  • fetch that commit's manifest and pin the musl build from it;
  • require the tree's own source.json to list the same digest.

  This is the same check RemoteInstaller.plan does for SSH hosts. A release build, a pin-mode bundle, and a dirty or unpublished build behave as before.

• It now returns PinnedPayload { path, sha256, commit }. machine update treats a machine already on the publishing commit as current (same_tree). Without this, a tree-mode app whose own commit differs from the publishing commit would update the machine on every send.

• The machine_update_unavailable message no longer says that DEV builds cannot update machines (item 1 of Cloud machine update from DEV builds: follow-ups from #30258 #30373).

Tests

cmux-ci test on the Linux pool:

• cargo fmt --check: clean.
• cargo test -p cmux-remote --lib published_pin_tests: 4 passed, including the new a_tree_bundle_takes_its_trees_publishing_commit.
• cargo clippy -p cmux-remote -p cmux-tui --all-targets -D warnings: clean.
  Agent session: agent session

🤖 Generated with Claude Code

[teamleaderleo]

Review (subagent claude-opus-5-5 medium): SHIP at 40b7c36

No blocking findings. The tree fallback checks what RemoteInstaller.plan checks: the source.json key, a 40-hex publishing commit, that commit's manifest, and that the tree lists the same digest. Everything goes over HTTPS, and the payload is verified against that digest before it is staged. Release and pin-mode builds are unchanged.

Follow-ups (filed as one issue):

1. same_tree is checked after pinned_payload, so a machine that is already current still costs three fetches.
2. No test covers the same_tree branch.
3. A source.json with no binaries gives machine_update_payload_rejected when it should give unavailable.
4. bundled_tree_key reads cmux-tui.version beside current_exe, which a symlinked binary does not find.
5. A dirty local build of a tree-mode bundle pins the clean published tree.

[teamleaderleo]

Owned by an agent session · session

[github-actions]

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

Review 40b7c36: 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=pr30421 -f ref=cloud-machine-update-tree-pin -f platform=macos -f backend_mode=local

[blacksmith-sh]

Found 15 test failures on Blacksmith runners:

Failures

Test	View Logs
/tmp/tmpo4o__uif/summary-missing.json (live):/summary-missing.json (live):	View Logs
/tmp/tmprqp4g8x4/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
nightly must build and hand off the macOS 26 helper and Xcode 26.5 app before publishin g/ nightly must build and hand off the macOS 26 helper and Xcode 26.5 app before publishin g	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

...and 5 more test failures. View all on Blacksmith: run 41285759871, run 41285759817

^{Need help on this PR? Tag @codesmith-bot with what you need.}

[teamleaderleo]

Superseded by #30604. #30258, which this PR built on, was reverted in #30438 for the CmuxNextApp line ratchet. #30604 re-lands this PR's Rust content with the reverted Rust half, byte-identical and with no CmuxNextApp lines, so this PR now conflicts with base. Closing in favour of #30604.