Customize: Remove deprecated nav menu classes

[westonruter]

The following classes are deprecated in 4.9 and can be removed in 5.0:

• wp.customize.Menus.NewMenuControl (in JS)
• WP_Customize_New_Menu_Section (in PHP)
• WP_Customize_New_Menu_Control (in PHP)

These classes are not used by plugins and they are not used in core. For more, see #42357.

[westonruter]

In 42034:

Customize: Deprecate nav menu classes that are no longer used, instead of removing them immediately.

• Deprecate PHP classes WP_Customize_New_Menu_Section and WP_Customize_New_Menu_Control.
• Deprecate JS class wp.customize.Menus.NewMenuControl.
• Also introduce wp.customize.Menus.createNavMenu() for logic to create nav menus separately from the logic for handling UI interactions.

Amends [41768].
See #40104, #42364.
Fixes #42357.

[Matthias Reuter]

I've created a diff with the patch to remove the classes mentioned.

[desrosj]

@Matthias Reuter are you able to refresh the patch? It is not applying to trunk currently.

[desrosj]

Sorry, incorrect tag above. @matthias-reuter.

[jorbin]

As 5.2 is now in beta and this was something that needed early attention, I'm removing it from the milestone.

[jrf]

Renewed patch.

[jrf]

I have create a new patch for the removal of the wp.customize.Menus.NewMenuControl (in JS) and the formal deprecation of the PHP WP_Customize_New_Menu_Section and WP_Customize_New_Menu_Control classes.

As those PHP classes have now been in Core for much longer than originally intended, I'm hesitant about removing them outright and have opted for aggressive deprecation instead.

[desrosj]

Thanks @jrf! I tend to agree with you on not straight up removing the classes. If someone is able to do a scan of the plugin directory and there are no plugins using these classes, I think we could reconsider.

42364.2.diff​ just adds the @deprecated tag to the function docblocks in addition to the _deprecated_file() and _deprecated_function() calls.

These changes should also get a brief dev note, just in case any plugins or themes are using them.

Since this is marked early, I'm going to commit this so it can have some soak time.

[desrosj]

In 46637:

Customize: Formally deprecate unused Customizer classes.

The WP_Customize_New_Menu_Control and WP_Customize_New_Menu_Section PHP classes and wp.customize.Menus.NewMenuControl JS class were deprecated in 4.9 through [42034] with the intention of removing them in 5.0. Since more time has passed than originally intended, this change leaves WP_Customize_New_Menu_Control and WP_Customize_New_Menu_Section to prevent any potential backwards compatibility issues, and formally deprecates them. The wp.customize.Menus.NewMenuControl JS class is removed.

Props weston.ruter, matthias-reuter, jrf.
Fixes #42364.

[audrasjb]

Quick dev note published: ​https://make.wordpress.org/core/2020/02/12/formal-deprecation-of-some-unused-customizer-classes-in-wordpress-5-4/