Plugin localization: private RU/EN domain

Addon translations need a private domain. This separates identical keys from game strings and other plugins. Editor and running-project locales can differ: do not change global project locale for a tool panel.

Complete RU/EN example

Create asset://addons/docs_localized/, save LocalizedDockPlugin.cs and plugin.cfg, build, and enable:

using Reckfell;

[Tool]
public partial class LocalizedDockPlugin : EditorPlugin
{
    public const string DomainName = "addons/docs_localized";
    private TranslationDomain? _domain;
    private Translation? _en, _ru;
    private EditorDock? _dock;
    public override void _EnterTree()
    {
        _domain = TranslationServer.GetOrAddDomain(DomainName);
        _domain.SetLocaleOverride(EditorInterface.Singleton.GetEditorLanguage());
        _en = new Translation { Locale = "en" };
        _en.AddMessage("Localized plugin", "Localized plugin");
        _en.AddMessage("Inspect settings", "Inspect settings");
        _ru = new Translation { Locale = "ru" };
        _ru.AddMessage("Localized plugin", "Локализованный плагин");
        _ru.AddMessage("Inspect settings", "Проверить настройки");
        _domain.AddTranslation(_en); _domain.AddTranslation(_ru);
        _dock = new EditorDock { Name = "DocsLocalizedDock", DefaultSlot = EditorDock.DockSlot.LeftUl };
        _dock.SetTranslationDomain(DomainName);
        _dock.Title = _dock.Tr("Localized plugin");
        _dock.AddChild(new Button { Name = "Action", Text = "Inspect settings" });
        AddDock(_dock);
    }
    public override void _ExitTree()
    {
        if (_dock is not null) { RemoveDock(_dock); _dock.QueueFree(); _dock = null; }
        TranslationServer.RemoveDomain(DomainName);
        _domain?.Dispose(); _domain = null;
        _en?.Dispose(); _ru?.Dispose(); _en = null; _ru = null;
    }
}

[plugin]
name="Docs localized dock"
description="Private translation domain with RU and EN messages"
author="Reckfell documentation"
version="1.0.0"
script="LocalizedDockPlugin.cs"

Two small dictionaries are created in code, avoiding hidden translation-file dependencies. For a larger addon, load your Translation resources into the same domain; this suite did not test PO/CSV import.

What provides isolation

GetOrAddDomain("addons/docs_localized") creates or returns the uniquely named domain. This code owns it; do not use the main domain's empty name or remove a domain shared with another addon.

SetLocaleOverride(GetEditorLanguage()) selects editor UI language on activation rather than game language. Assign SetTranslationDomain() to the panel before adding children; the button inherits it. Its checked GetTranslationDomain() matched the addon name without changing global project locale.

Button.Text retains the source key. Comparing it with a Russian string alone does not test localization: translation is used during display. Direct Tr() returned Inspect settings for en and Проверить настройки for ru. A missing key returned source text.

The example sets EditorDock.Title to an already translated string at panel creation. It does not promise live updates of all strings when editor language changes: disable/enable afterward or explicitly refresh your own UI.

Inspector fields and other objects

Domain inheritance follows the Entity hierarchy. EditorInspectorPlugin is a separate ref-counted object, and its EditorProperty enters the Inspector tree. Do not assume they inherit an EditorPlugin domain automatically. Assign domains explicitly when adapting them and test captions separately; see the Inspector example.

Deactivation

Unregister and remove the owned panel first, then remove the plugin-owned domain and release dictionaries. If modules share a domain, use one owner with usage tracking rather than unconditional RemoveDomain by each participant.

Checks covered child inheritance, editor-language override, RU/EN lookup, source-key fallback, unchanged project locale, and cleanup across reenablement. Visible translated pixels, PO/CSV import, plural forms, numeric formatting, Inspector-field translation, and live language switching were not tested.