Desktop: project icon discovery can block sidecar for minutes on large directory trees

[oomp]

Summary

OpenCode Desktop can make its local sidecar server unresponsive for many minutes when opening a git project that contains a very large directory tree. The trigger appears to be desktop-enabled project icon discovery.

In the packaged desktop app, preferAppEnv() forces:

OPENCODE_EXPERIMENTAL_ICON_DISCOVERY: "true"

Then Project.fromDirectory starts Project.discover, which runs an unbounded recursive glob over the whole worktree:

fs.glob("**/favicon.{ico,png,svg,jpg,jpeg,webp}", {
  cwd: input.worktree,
  absolute: true,
  include: "file"
})

On worktrees with a pathological number of directories, this can monopolize the sidecar process. While this is happening, even /global/health does not respond, so the Desktop app reports the local server as down. After the glob eventually finishes, the server becomes healthy again.

Environment

• OpenCode Desktop: 1.15.12
• OS: Windows
• Project type: git worktree
• Desktop local sidecar process: Electron node.mojom.NodeService

Observed behavior

1. OpenCode Desktop starts normally and the sidecar reports ready.
2. Opening a specific git worktree triggers directory-specific requests.
3. The sidecar stops responding even to /global/health.
4. One sidecar thread burns CPU for many minutes.
5. After enough time passes, the server recovers and endpoints respond again.

This looks like a CPU-bound scan rather than a crash or permanent deadlock.

Evidence

In a real project, a runtime/cache directory contained a very large tree:

data/free-runtime/stale-leases

A safe diagnostic scan that intentionally skipped .git, .venv, venv, Backups, and editor/service directories still did not finish after 30 seconds and had already visited:

177350 directories
6865 files
0 favicon matches

Chromium request logs showed a long gap where only health/event requests were attempted; after the CPU-bound work completed, normal endpoints resumed.

The issue reproduces in Desktop, but not in CLI-like usage, which is consistent with Desktop forcing OPENCODE_EXPERIMENTAL_ICON_DISCOVERY=true.

Expected behavior

Project icon discovery should not be able to make the sidecar/local server unavailable.

At minimum, it should:

• honor common ignore directories such as .git, node_modules, .venv, venv, dist, build, cache/runtime directories, and ideally configured watcher/gitignore excludes;
• use a bounded search strategy rather than **/favicon... over the entire worktree;
• have a timeout or match/entry limit;
• not block sidecar health/API responsiveness;
• allow users to explicitly disable desktop icon discovery via env/config instead of Desktop unconditionally forcing it on.

Suggested fixes

Possible options:

1. Do not force OPENCODE_EXPERIMENTAL_ICON_DISCOVERY=true in Desktop when the user explicitly set it to false.
2. Replace the full recursive glob with bounded candidate paths, for example root/public/static/assets/app directories with limited depth.
3. Apply the same ignore/protected directory policy used elsewhere before scanning.
4. Run icon discovery in a cancellable worker/child process with timeout/limit so it cannot block the sidecar event loop.
5. Skip discovery once a project has any explicit icon override, and expose that as a normal UI/config fallback.

Workaround

Setting an explicit project icon override prevents Project.discover from scanning that project, but users should not need to patch local state to keep Desktop responsive.

[github-actions]

This issue might be a duplicate of or related to existing issues. Please check:

• Electron desktop app hangs on startup with large .gitignored projects #20977: Similar symptom (Desktop sidecar pegging CPU / becoming unresponsive on large projects), though that issue traces the cause to OPENCODE_EXPERIMENTAL_FILEWATCHER rather than icon discovery. The underlying pattern is the same: Desktop forcing an experimental env var triggers an unbounded scan that blocks the sidecar.
• [FEATURE]: Favicon being rendered on the Desktop sidebar for any application #19962: Related to the favicon/icon discovery feature itself (rendering project favicons in the sidebar), which is the feature this bug report affects.