desktop: attachment file picker fails instantly with "Desktop IPC handler failed" (regression from 2.0.6) #50621

Summary

Clicking the "Image and File" attach menu (Ctrl+U) in OpenCode Desktop 2.0.13 on Windows instantly shows a toast Request failed / Desktop IPC handler failed, and the native file dialog never opens. Desktop 2.0.6 worked fine, so this looks like a regression between 2.0.6 and 2.0.13.

Environment

• opencode version: Desktop 2.0.13 (release, channel latest, confirmed via debug-log manifest.json); CLI on PATH is 2.0.10 (C:\Users\<user>\.opencode\bin\opencode.exe); last known good Desktop: 2.0.6
• OS: Microsoft Windows [Version 10.0.26200.9457] (win32 x64)
• Terminal: N/A (Desktop GUI issue)
• Shell: C:\WINDOWS\system32\cmd.exe
• Install/channel: release / latest
• Active plugins: none (no plugin entries in global or project config; global config only defines mcp.context7 and a custom lmstudio provider)

Reproduction

1. Open OpenCode Desktop 2.0.13 on Windows.
2. In the prompt composer, click + → Image and File (or press Ctrl+U).
3. A toast Request failed / Desktop IPC handler failed appears immediately. The native file picker never opens.

Expected Behavior

The native OS file picker (dialog.showOpenDialog) should open so an image/file can be selected for attachment, as it did in 2.0.6.

Actual Behavior

Instant failure with no dialog. Exact UI text: Request failed / Desktop IPC handler failed. 100% reproducible.

Isolation results:

• The folder picker (open project) works.
• Drag & drop and clipboard paste of images work (they bypass the dialog).
• Only the attachment file picker (FilesOpenFilePicker) fails, before any file is chosen, so this is not the 20 MiB attachment budget.

Additional Context

Code path in 2.0.13 (packages/desktop):

• packages/app/src/composer/attachments/attachments.ts pick() calls the picker with { defaultPath: input.directory(), multiple: true } and no title/extensions.
• packages/desktop/src/renderer/platform/files.ts forwards that to FilesOpenFilePicker.
• packages/desktop/src/main/files/index.ts DesktopFiles.openFilePicker passes it straight to dialog.showOpenDialog({ ..., defaultPath, filters: undefined }) with Effect.orDie, so any throw (e.g. from defaultPath or nativeT("desktop.dialog.chooseFile")) surfaces only as the generic IPC failure.
• The directory picker sends no defaultPath, which matches the observation that only the file picker fails.

Log evidence from Export debug logs (2.0.13, win32 x64):

• desktop/*/main.log contains no DesktopFiles/openFilePicker defect entry.
• desktop/*/renderer.log shows: Unable to fetch & register locale data for 'ja', falling back to 'en-US'. Cause: SyntaxError: Unexpected token 'H', "HTTP/1.1 4"... is not valid JSON.
• A stale 2.0.10 serve --service was fighting the 2.0.13 service on the same port (reason: 'version-mismatch', GET /api/info → 503, event-stream ERR_CONNECTION_RESET). After killing the stale service so only the staged 2.0.13 serve --service runs, the picker still fails, so the service flap is not (or not the only) cause.

Workaround: attach via drag & drop or paste instead of the attach menu.