Hosted pages do not support more than one specialization of a language

[mmanes]

Description

When adding localization messages to a theme, only one specialization of a language will be available on the rendered pages.

Affects versions

1.46.0

Steps to reproduce

Steps to reproduce the behavior:

1. Create a custom theme and edit it
2. Select "Messages"
3. Add localizations for "English (Great Britain)" and "English (United States)" in addition to the default
4. Assign the new theme to a Tenant or Application
5. Navigate to the Login URL for the Application
6. Notice that the language drop-down only displays two "English" options. Inspecting the select element will show that it only contains "en" and "en_GB" options.

Expected behavior

All localized languages should be available in the hosted pages.

Community guidelines

All issues filed in this repository must abide by the FusionAuth community guidelines.

Additional information

See: Theme::additionalLocales()

[robotdan]

I tried with en and en_CA (Canada) and fr (French) and it worked correctly.

But I can recreate if I use en_GB or en_AT for example.

So perhaps some issue with the suffix handling?

[josephk96]

@robotdan ,

I was able to reproduce this with zh_CH and zh_TW - only one Chinese option will be displayed in the form dropdown.

[LucasPMorris]

Related: #69

[mooreds]

Confirmed that this is still an issue on 1.59.0