Add a filter to disable the login screen language dropdown

[audrasjb]

The login screen language dropdown was introduced in [52058].

On the Make/Core devnote, @rickcurran suggested we add a filter to allow developers to disable the language dropdown. The typical use case could be a plugin which already add the feature.

Related: #43700.
Follow-up to [52058].

[ocean90]

Related ​[meta11378]

Trac ticket: https://core.trac.wordpress.org/ticket/54675

[audrasjb]

The PR above adds the filter.
It correctly disable the language switcher, using this hook:

add_filter( 'display_login_language_dropdown', '__return_false' );

[hellofromTonya]

Pulling into 5.9 and changing the type to defect. It's not technically a bug, but rather an opportunity to provide the ability to turn off the feature introduced in 5.9.

This one is part of #43700, which has a dev note. Marking needs-dev-note as the new filter will need to be added to ​https://make.wordpress.org/core/2021/12/20/introducing-new-language-switcher-on-the-login-screen-in-wp-5-9/.

[costdev]

Test Report

Env

• WordPress: trunk (with ​PR 2074 applied)
• Browser: Chrome v96.0.4664.110
• OS: Windows 10 (WSL2)
• Theme: Twenty Twenty-Two
• Block Editor
• Plugin: None activated

Steps to test

1. Load /wp-login.php.
2. The languages dropdown should be visible.
3. Add the following to Twenty Twenty-Two's functions.php file and Save:

   add_filter( 'display_login_language_dropdown', '__return_false' );
   

4. Refresh /wp-login.php.
5. The languages dropdown should no longer be visible.

Results

• Before adding the filter, the languages dropdown was visible.
• After adding the filter, the languages dropdown was no longer visible.
• All works as expected. 👍

@costdev did a test report https://core.trac.wordpress.org/ticket/54675#comment:6. Its as expected ✅

[hellofromTonya]

Marking ​PR 2074 for commit.

[audrasjb]

Self assigning for commit

[audrasjb]

In 52404:

Login and registration: Add a filter to allow to disable the Login screen language dropdown.

This change introduces the display_login_language_dropdown filter which allows to disable the Login screen language dropdown.

Follow-up to [52058].

Props rickcurran, audrasjb, ocean90, hellofromtonya, costdev, johnbillion.
Fixes #54675.

[audrasjb]

In 52405:

Coding Standards: Remove unwanted whitespaces after [52404].

Follow-up to [52404].

See #54675.

Committed in https://core.trac.wordpress.org/changeset/52404

[rickcurran]

Hi, sorry, not a huge issue but thought it worth highlighting here, I just went to apply this to a site running the latest RC4 release to test preventing the language dropdown from showing on the login page and it wasn't working for me. I then noticed that the filter names were subsequently renamed in another code change on 03/01/2022 to login_display_language_dropdown instead of the original display_login_language_dropdown that this ticket originally defined it as. It wasn't until I double-checked my wp-login.php file of my site that I noticed that it had changed.

Thanks!

Replying to audrasjb:

In 52404:

Login and registration: Add a filter to allow to disable the Login screen language dropdown.

This change introduces the display_login_language_dropdown filter which allows to disable the Login screen language dropdown.

Follow-up to [52058].

Props rickcurran, audrasjb, ocean90, hellofromtonya, costdev, johnbillion.
Fixes #54675.

[SergeyBiryukov]

Replying to rickcurran:

I then noticed that the filter names were subsequently renamed in another code change on 03/01/2022 to login_display_language_dropdown instead of the original display_login_language_dropdown that this ticket originally defined it as. It wasn't until I double-checked my wp-login.php file of my site that I noticed that it had changed.

Thanks for the comment! The filter names were indeed changed in #54696 for more consistency.