Add Platform.System.os_description/0

[dominicletz]

Summary

• Adds Desktop.Platform.System.os_description/0 as the backend-safe replacement for :wx_misc.getOsDescription/0
• Implements it on Wx (:wx_misc), Json (Desktop.Bridge.Protocol), and Browser (nil)
• Mock returns ~c"Mock OS"; facade normalizes charlist/binary and trims empty → nil
• Guard + tests so apps do not call :wx_misc.getOsDescription/0 directly

Needed by diode-drive: after the mobile bridge embed (#73), OS.model/0 still called :wx_misc.getOsDescription/0, which targeted the removed Hex Bridge GenServer and crashed Android device linking.

Test plan

• NO_WX=1 mix test test/desktop/backend/json_test.exs test/desktop/backend/browser_test.exs test/desktop/regression/beam_wx_calls_test.exs --exclude wx
• mix test.guard
• xvfb-run mix test.wx (or local wx) for T-WX: os_description via Platform.System

Made with Cursor

[gemini-code-assist]

Code Review

This pull request introduces Desktop.Platform.System.os_description/0 as a backend-safe replacement for :wx_misc.getOsDescription/0 across different backends (Wx, Json bridge, and Browser). It includes corresponding backend implementations, tests, documentation updates, and a guard rule to prevent direct calls to :wx_misc.getOsDescription/0. Feedback suggests refactoring os_description/0 in lib/desktop/platform/system.ex to avoid piping a block directly into a case statement, which is an Elixir anti-pattern, and instead bind the block's result to a local variable first.

Important

The consumer version of Gemini Code Assist on GitHub is being sunset. Starting June 18, 2026, new organization installations will be blocked, and all code review activity will officially cease on July 17, 2026.
For more details on the timeline and next steps, please review the Help Documentation.

[gemini-code-assist]

Piping the result of a block directly into a case statement is generally considered an anti-pattern in Elixir (as highlighted by tools like Credo). It can make the code harder to read and debug.

Instead, bind the result of Helpers.with_wx_env/1 to a local variable first, and then perform the case match on that variable.

  def os_description do
    raw_desc =
      Helpers.with_wx_env(fn ->
        case impl().os_description() do
          desc when is_binary(desc) -> desc
          desc when is_list(desc) -> List.to_string(desc)
          _ -> nil
        end
      end)

    case raw_desc do
      nil ->
        nil

      str ->
        case String.trim(str) do
          "" -> nil
          trimmed -> trimmed
        end
    end
  end

References

1. Avoid piping into control flow structures like case, if, or cond to maintain readability and idiomatic Elixir style. ^(link)

[cursor-automation]

@gemini review this PR