[mondalaci]

Problem

Export device configuration does nothing on Linux, and Import device configuration does nothing either. The log ends with:

[FileDialogService] save user configuration dialog, defaultPath: /home/henrik/UserConfiguration.json
[6293:1015/232605.430028:ERROR:components/dbus/xdg/request.cc:173] Request ended (non-user cancelled).

Root cause

Request ended (non-user cancelled) is Chromium's message for dbus_xdg::ResponseCode::kOther (response code 2): the xdg-desktop-portal FileChooser backend aborted the request. ui/shell_dialogs/select_file_dialog_linux_portal.cc maps any portal error onto a regular cancellation (FileSelectionCanceled), so Electron resolves { canceled: true } and Agent shows nothing.

This is a known portal-backend failure, not a user cancel and not a path problem, for example xdg-desktop-portal-gnome without Nautilus (nix-community/home-manager#9996) or Ubuntu 26.04 (signalapp/Signal-Desktop#8040).

#3069 blamed a relative defaultPath and only made it absolute. That cannot explain this report: the path is already absolute, and code 2 originates in the backend.

Fix

Keep the native dialogs (still always with an absolute default path so they work where the portal is healthy), but stop depending on them:

• packages/uhk-agent/src/services/file-dialog.service.ts
  • Detect a dialog that resolves almost instantly (the portal aborting before any dialog can appear) as opposed to a real user cancel.
  • Save: write the configuration in the main process itself, into the remembered configuration folder when it still exists and otherwise into the downloads folder, creating the folder and never overwriting an existing file (UserConfiguration (1).json). Report the written path.
  • Open: report portalFailed instead of a silent cancel.
  • List the .json/.bin files of the import folder and read the file the in-app picker chose. The read channel only accepts files inside that folder.
• packages/uhk-common/src/models/file-dialog.ts — OpenUserConfigDialogResult.portalFailed, SaveUserConfigDialogResult.savedWithoutDialog, UserConfigFileInfo, ListUserConfigFilesResult.
• packages/uhk-common/src/util/ipcEvents.ts — fileDialog.listUserConfigFiles, fileDialog.readUserConfigFile.
• packages/uhk-web/src/renderer/services/electron-file-dialog.service.ts — the save is now a pass-through (the main process writes the file); the open falls back to an in-app picker.
• packages/uhk-web/src/renderer/components/user-config-file-picker/ — the picker Agent draws itself (a Bootstrap modal listing the configuration files of the import folder).
• packages/uhk-web/src/app/store/effects/user-config.ts — the notification names the actual written path instead of asserting the downloads folder.

This replaces the first iteration of this PR, which fell back to the renderer's file-saver download: that path returns no path, wrote nothing, and still claimed success, so the reporter saw Saved the user configuration without a save dialog null with no file on disk.

Why an in-app picker instead of <input type="file">

The first version of the open fallback used the renderer's <input type="file"> picker on the assumption that it is a different code path from Electron's dialog.showOpenDialog. It is not: Chromium serves both through ui/shell_dialogs/select_file_dialog_linux_portal.cc, so the renderer picker hits the same broken backend (and, invoked after the awaited IPC round-trip, can also be blocked for lack of user activation). The reporter's retest on the 2f2b968d build confirmed it: export worked, import still logged the open dialog closed after 67 ms without appearing and did nothing. Agent therefore draws its own picker and reads the file in the main process, avoiding the portal entirely.

Verification

• npx tsc --noEmit -p packages/uhk-agent/tsconfig.json — clean
• npx tsc --noEmit -p packages/uhk-web/tsconfig.json — clean (only pre-existing errors in group-macros-by-name.test.ts)
• npx ng build --configuration=production --project=uhk-renderer — success (only pre-existing warnings)
• npm test in packages/uhk-web — 33/33 pass
• npx eslint <changed files> — clean

Notes

• Export no longer depends on any dialog, so it is deterministic whenever the portal is broken.
• Import does not depend on any Chromium file chooser either: it lists the files of the import folder (remembered folder, else downloads) and reads the chosen one in the main process. A configuration that is not in that folder can be imported by copying it there; the dialog shows the folder.
• The environment-level remedy is to install/select xdg-desktop-portal-gtk (or add Nautilus for the GNOME backend); this change only prevents the silent failure.
• Supersedes fix: open the device configuration export dialog on Linux #3069.
• Needs retesting by the reporter on Arch (available again around Oct 26).