Avoid translating several times widget media default strings

[Chouby]

The translation being a rather expensive process, we should avoid to translate the same string several times.

The class Widget_Media is a base class for 4 widgets. Its constructor is thus called 4 times, meaning that all the strings included in this constructor are translated 4 times.

[Chouby]

Avoid 27 duplicate translations

Trac ticket: https://core.trac.wordpress.org/ticket/54561

[audrasjb]

The above PR refreshes the patch against trunk and updates @since mentions.
GH Tests are passing.
Adding needs-testing keyword to ensure it doesn't break anything :)

[audrasjb]

Removing needs-testing keyword: the patch looks good on my side, it doesn't break anything on the Classic Widgets screen and it successfully mutualizes translations.

[peterwilsoncc]

Does the static need to be cleared on change_locale to account for language switching plugins or similar? I set my site's language to Français and it all seemed good but I'd rather ask as others on this ticket deal with translations more often than I.

[audrasjb]

I don't think any specific action is needed. What do you think @Chouby?

[Chouby]

The usages I remember having seen for switch_to_locale() are for sending emails, creating documents such as PDF invoices and displaying the admin bar in a different language than the main language on frontend.

I don't foresee a usage which wpuld require to switch the locale before displaying the backend of widgets.

However, if we want to be on the safe side, then it would indeed be necessary to reset the static variables on change_locale.

[peterwilsoncc]

Thanks @Chouby and @audrasjb.

For the sake of a single line in default-filters.php, clearing the static on change_locale seems safest.

I'd be surprised if failing to do so broke a plugin but similar enough surprises have happened in the past.

[audrasjb]

Alright @peterwilsoncc @Chouby, but I'm unsure what would be the best function to hook on in default-filters.php. Any thought?

[peterwilsoncc]

@audrasjb I think you'd need to add a reset method reset_default_labels() similar to the one in WP_Post_Type and then hook on to that in default-filters.

[audrasjb]

I'm sorry, but I'm not sure where to hook/call the reset labels function… (and I'm not sure it's really needed too). Halp :)

[costdev]

If the reset_default_labels() method is going to be added, I think default-filters.php would just need this:

add_action( 'change_locale', array( 'WP_Widget_Media', 'reset_default_labels' ) );

As for "where" in default-filters.php, the change_locale hooks for Post and Taxonomy are under their respective comments, so this hook could just go under the // Media. comment at ~L621.

What do you think @audrasjb?

[Chouby]

Refresh patch and reset default labels on change_locale

[Chouby]

The patch required some refresh due to recent changes in default labels. 54561.2.patch also adds a way to reset the default labels on change_locale.

[audrasjb]

Thanks for the patch @Chouby.
Let's roll.

[audrasjb]

PR refreshed with the above patch: ​https://github.com/WordPress/wordpress-develop/pull/2123/files
Waiting for unit tests to pass.

[audrasjb]

In 53158:

Widgets: Avoid 27 duplicate translations in Media Widgets constructor.

This changeset rationalizes the declaration of translation strings in the Media Widgets constructor.

Props Chouby, audrasjb, peterwilsoncc, costdev.
Fixes #54561.

Committed in https://core.trac.wordpress.org/changeset/53158