Builtin PlayWith(core) function does not work

Bug report

Describe the bug

Builtin PlayWith() function is a function that can be called using keymap to play video in a specific player core (external player).

This function has not worked as described for many years as others have pointed out: #24784, #20397. It seems a refactor around the time of Isengard or Jarvis probably broke it.

Expected Behavior

Play the selected item with the specified player core.

Actual Behavior

It plays with the default player.

Possible Fix

Maybe look at the code back in Isengard or Jarvis, that seems to be the last time this code worked.

To Reproduce

Steps to reproduce the behavior:

1. playercorefactory.xml from Wiki modified to work with flatpak:

<playercorefactory>
  <players>
    <player name="MPV" type="ExternalPlayer" audio="false" video="true">
      <filename>flatpak-spawn</filename>
      <args>--host /usr/bin/mpv --fs=yes "{1}"</args>
      <hidexbmc>false</hidexbmc>
    </player>
  </players>
</playercorefactory>

1. keymaps/keyboard.xml

<keymap>
  <global>
    <keyboard>
      <f6>PlayWith(MPV)</f6>
    </keyboard>
  </global>
</keymap>

1. Enable external player flatpak override tv.kodi.Kodi --talk-name=org.freedesktop.Flatpak
2. Confirm external player works using Context Menu Play With
3. Press F6 to call PlayWith(MPV) function.

Debuglog

The debuglog can be found here: https://paste.kodi.tv/vidawaxoce.kodi

Your Environment

Used Operating system:

• Android

• iOS

• tvOS

• Linux

• macOS

• Windows

• Windows UWP

• Operating system version/name: Ubuntu 24.04

• Kodi version: 21.3