Web: worktree paths remain as separate projects due to sandbox→root collapse cycle when sandboxes includes root

[benoitheinrich]

Description

While testing the fix for #14082 (PR: #14287), I found a Web UI bug: when opening a git worktree via the + / “Open project” picker, the worktree directory is persisted as a top-level project entry in the sidebar instead of collapsing under the repo root as a workspace. This persists across reloads.

The backend correctly resolves the worktree to the root project (same project id + worktree), and /project + /global/event include the correct sandboxes mapping, but the UI collapse logic fails when the root directory is also present in sandboxes, creating a self-edge and tripping the cycle guard.

Plugins

None

OpenCode version

1.2.17 (built from branch fix-14082-sidebar-sandbox-sessions, opencode --version shows 0.0.0-fix-14082-sidebar-sandbox-sessions-…)

Steps to reproduce

1. Start opencode web (or opencode serve + connect from the Web UI).
2. Open a git repo root directory, e.g.:
   • root: /path/to/repo
3. Enable “workspaces” for the project in the sidebar.
4. Create a git worktree from the repo, e.g.:
   • worktree: /path/to/_wt/repo-feature-branch
5. In the Web UI, click + (Open project / picker) and open the worktree directory /path/to/_wt/repo-feature-branch.
6. Observe: the sidebar shows separate top-level project entries for both:
   • /path/to/repo
   • /path/to/_wt/repo-feature-branch
     and the worktree entry has workspaces disabled by default.
7. Reload the page: the worktree still shows as a separate project.

Expected

If the worktree directory belongs to an existing project (backend indicates this via project.sandboxes), the UI should collapse it under the root project and show it as a workspace, not a separate top-level project entry.

Actual

Worktree stays pinned as a separate top-level project, even though the server reports it as a sandbox of the root project.

Evidence / debugging notes

Backend correctly reports root + sandboxes.

GET /project/current with header x-opencode-directory: /path/to/_wt/repo-feature-branch returns:

• worktree: /path/to/repo
• sandboxes includes both /path/to/repo and /path/to/_wt/repo-feature-branch.

GET /project returns a project row for /path/to/repo with:

"sandboxes": [
  "/path/to/repo",
  "/path/to/_wt/repo-feature-branch",
  ...
]

/global/event emits project.updated for /path/to/repo with the same sandboxes list (including root + worktrees).

The Web UI collapse logic (in packages/app/src/context/layout.tsx) builds a map sandbox -> project.worktree for all entries in sandboxes. When sandboxes includes the root, it creates a self-edge map[root]=root. Resolving a worktree becomes worktree -> root -> root, hits the cycle guard, and returns the original directory, preventing collapse.

Potential fix

In the UI sandbox→root mapping, skip sandbox === project.worktree (do not create root -> root), so rootFor(worktree) resolves to the root worktree and the existing collapse effect can remove the pinned worktree project entry.

Related

• Found while testing fix for Web: Sidebar session list hides worktree/sandbox sessions after 1.2.6 upgrade (filters to current directory only) #14082 / PR fix(project): repair split project IDs across worktrees #14287
• Possibly related symptom class: Worktrees doesn't work well on web #10468, [BUG][Windows] Same workspace appears twice in sidebar (one empty, one populated) due to path variant mismatch #14571

(Additional note: opencode web proxies the UI from app.opencode.ai; the fix is expected to be in packages/app.)