Destroying a managed worktree leaves its local branch behind

[plx]

Summary

Destroying a managed worktree removes the checkout and its Git worktree metadata but leaves the generated bb/<slug>-<threadId> local branch in the source repository. The worktree guide promises that the branch is removed with the worktree, so every completed managed environment currently leaves a permanent branch behind.

Versions and environment

• bb 0.40.0 from source at f4bbc2fe81a9b7639ff9a7396e172bddd89109e4 (origin/main)
• macOS 27.0, Apple silicon
• Node.js 22.19.0
• Local host, fresh dev data directory, managed worktree environment
• Provider: codex CLI 0.151.0; provider choice is not involved in cleanup

Steps to reproduce

1. Create a scratch Git repository and register it as a project:

   repo=$(mktemp -d /tmp/bb-managed-branch-repro.XXXXXX)
   git -C "$repo" init -b main
   git -C "$repo" config user.name "BB Repro"
   git -C "$repo" config user.email bb-repro@example.com
   touch "$repo/README.md"
   git -C "$repo" add README.md
   git -C "$repo" commit -m initial
   project_id=$(bb project create --name "Managed branch cleanup repro" --root "$repo" --json | jq -r .id)

2. Spawn a thread in a managed worktree, then wait for it to become idle:

   thread_id=$(bb thread spawn --project "$project_id" --new-environment worktree --provider codex --permission-mode accept-edits --title "Branch cleanup repro" --prompt "Reply only with ok." --json | jq -r .id)
   bb thread show "$thread_id" --json

3. Record the generated branch, archive the thread, and wait until its environment reaches destroyed after the managed-environment retirement grace and cleanup sweep:

   branch=$(bb thread show "$thread_id" --json | jq -r .environment.branchName)
   bb thread archive "$thread_id" --json
   bb thread show "$thread_id" --json

4. Inspect the source repository:

   git -C "$repo" worktree list --porcelain
   git -C "$repo" branch --list "$branch"

The smallest direct reproduction is the same createWorktree → removeWorktree sequence in @bb/host-workspace; no provider process is required for the leak.

Expected vs actual

Expected after environment status becomes destroyed:

$ git -C "$repo" worktree list --porcelain
worktree /private/tmp/bb-managed-branch-repro.BDoFHZ
HEAD 35593bf58c11ea9e593760e003feb05206f10971
branch refs/heads/main

$ git -C "$repo" branch --list 'bb/branch-cleanup-repro-thr_wzberxex69'

Actual:

$ git -C "$repo" worktree list --porcelain
worktree /private/tmp/bb-managed-branch-repro.BDoFHZ
HEAD 35593bf58c11ea9e593760e003feb05206f10971
branch refs/heads/main

$ git -C "$repo" branch --list 'bb/branch-cleanup-repro-thr_wzberxex69'
  bb/branch-cleanup-repro-thr_wzberxex69

The managed worktree is gone, but its local branch remains.

Evidence

• Reproduced with thread thr_wzberxex69, environment env_x8skdy9bid, and project proj_8myi5vfrh6 in a fresh local dev instance. To avoid waiting for the five-minute unarchive grace during the source repro, I backdated only retire_requested_at and restarted the server; the normal destroy command then completed and set the environment to destroyed.
• removeWorktree resolves the common Git directory and runs git worktree remove, but never deletes the checked-out branch.
• The worktree guide says cleanup removes the worktree "along with the branch" and warns users to push before the branch goes away.

What you ruled out

• Still reproduces on origin/main at f4bbc2fe81a9b7639ff9a7396e172bddd89109e4.
• Not Publish clean GitHub branch names from managed worktrees #2113: that issue concerns cleaner GitHub-facing names; this bug is failure to remove the local managed branch at destroy time.
• Not EnvironmentsArea has no release/delete/detach, so a managed worktree outlives its archived thread permanently #1911 or No sanctioned way to release a managed environment, so environments accumulate without bound #1949: those concern ways to initiate environment release; this reproduces after release already completes successfully.
• Detached or unmanaged workspaces are not implicated; only a managed worktree with a symbolic branch leaks a branch.
• Searches of open and closed issues for worktree branch, delete branch worktree, and branch archive worktree found no issue for this cleanup failure.

Suggested priority and effort (optional)

Medium — affects every successfully destroyed managed worktree and accumulates stale refs indefinitely; manual git branch -D is the only cleanup workaround. The fix is localized to host-workspace destruction but needs detached-HEAD and non-fatal deletion-failure handling.

Checks

• I reproduced this on the latest release or on main, or I say above that I could not.
• I searched open and closed issues for the same problem.
• If an agent wrote this, the body ends with > AGENT GENERATED and links the thread or report.

AGENT GENERATED

[bb-slop-cop]

🚨 SLOP COP 🚨 · new-issue-autopilot

• Classification: Type Bug · Priority Medium · Effort Low · Labels workspaces, confirmed-repro
• Report: https://get-bb.github.io/reports/issues/2724.html
• Verdict: REPRODUCED · Confidence: high
• Root cause: Worktree removal deletes the checkout metadata but does not delete its symbolic branch ref.
• Reproduction label: confirmed-repro
• No new pull request: Delete managed worktree branches on cleanup #2726 already links to this issue and remains open.