Missing i18n for Submenu Labels under "Select" Menu

[likesubject]

Problem Description

Submenu labels under the Select menu (e.g., "All", "Line", "Word") fail to display translated text when using non-English locales. This occurs because the menu labels in monaco-menu.ts were not properly internationalized

Original Code:

In @theia/monaco/src/browser/monaco-menu.ts, the buildMenuAction method did not apply localization handling to the label field. The original code directly used the raw label without passing it through the i18n system.

protected buildMenuAction(commandId: string, item: IMenuItem): MenuAction {
    const title = typeof item.command.title === 'string' ? item.command.title : item.command.title.value;
    const label = this.removeMnemonic(title);
    const order = item.order ? String(item.order) : '';
    return { commandId, order, label };
}

Modified Code:

protected buildMenuAction(commandId: string, item: IMenuItem): MenuAction {
    const title = typeof item.command.title === 'string' ? item.command.title : item.command.title.value;
    let label = this.removeMnemonic(title);
    const order = item.order ? String(item.order) : '';
    label = nls.localizeByDefault(label);
    return { commandId, order, label };
}

Environment:

• Theia Version: 1.58.3
• Operating System: Windows 10

Steps to Reproduce

1. Set the IDE to a non-English locale (e.g., Chinese or French).
2. Open the Select menu from the top menu bar.
3. Observe untranslated submenu labels (e.g., "All", "Line").

Expected Behavior: Labels should display translated text according to the configured locale.
Actual Behavior: Labels show raw English text.

Proposed Fix

Added nls.localizeByDefault() to ensure labels are processed for internationalization. Below is the code change:

protected buildMenuAction(commandId: string, item: IMenuItem): MenuAction {
    const title = typeof item.command.title === 'string' ? item.command.title : item.command.title.value;
    let label = this.removeMnemonic(title);
    const order = item.order ? String(item.order) : '';
+    label = nls.localizeByDefault(label);
    return { commandId, order, label };
}

[JonasHelming]

Thank you very much for this report. It seems you already found a solution, would you be interested in contributing this and get the credits?

[msujew]

Note that this isn't the right approach for localization of Monaco contributed labels. I wasn't aware of this, but it seems like the code for localizing Monaco was removed, see here. This will need to be re-enabled again.

[tsmaeder]

I had a quick look and it seems like putting the code back does not cause any major trouble, but it seems that the Monaco localisation code has change in the mean time. Not all menus are localized when restoring the code "as is".

[tsmaeder]

I particular, a localize2 message has been added.

[msujew]

I'll take a look at this on Monday, in case you aren't already on it @tsmaeder (I don't work on Fridays)

[tsmaeder]

Adding the following code fixes most of the problems:

import * as MonacoNls from '@theia/monaco-editor-core/esm/vs/nls';
import { nls } from '@theia/core/lib/common/nls';
import { FormatType, Localization } from '@theia/core/lib/common/i18n/localization';

Object.assign(MonacoNls, {
    localize(_key: string, label: string, ...args: FormatType[]): string {
        if (nls.locale) {
            const defaultKey = nls.getDefaultKey(label);
            if (defaultKey) {
                return nls.localize(defaultKey, label, ...args);
            }
        }
        return Localization.format(label, args);
    },
    localize2(_key: string /* | number when built */,
        label: string, ...args: FormatType[]): MonacoNls.ILocalizedString {
        const original = Localization.format(label, args);
        if (nls.locale) {
            const defaultKey = nls.getDefaultKey(label);
            if (defaultKey) {
                return {
                    original,
                    value: nls.localize(defaultKey, label, ...args)
                };
            }
        }
        return {
            original,
            value: original
        };
    }
});

However, there are some problems, in particular the "Paste" action in the editor context menu is not internationalized. I'll let you apply your greater experience with the topic on Monday :-)

[msujew]

I've created #15016 to fix this.