There is no error reporting in the Customizer (for upload failures)

[Fab1en]

As far as I know, there is no way to display an error to the user when he/she is using the theme customizer.

An error that I'm facing some time to time when I test WordPress locally is when wp-content/uploads is not writable. Then, uploading a new image to use as a background in the customizer does not work, but this fails silently.

This error reporting should be built-in inside WP_Customize_Control class so that any control that extends this class can throws a custom error and displays it to the user.

Depends on #35210.

[westonruter]

This is related to #29098, which would provide the general mechanism for sending back error codes/messages.

[westonruter]

It looks like #29098 may not be exactly what we need to communicate upload errors back to the Customizer. Instead of sending error messages back when customize_save happens, the actual upload error is going to happen when the setting is updated and the value gets synced with the Customizer preview.

[westonruter]

To work on as part of implementing the notification area (#35210).

See also:

• #31582: Catching PHP Fatal Errors on WordPress Theme Customizer
• #34893: Improve Customizer setting validation model

[chriscct7]

Punting to next release per discussion with @westonruter

[westonruter]

It seems the error being described here would make the most sense to display in the same location where error messages are displayed for setting validation (#34893). As such, the control API for error messages should be agnostic to whether it is a validation error or some other error message.

[westonruter]

Punting due to transactions being too large to finish patch and test in time for 4.6.

[westonruter]

I believe that his is now irrelevant because the upload control now extends the media control as of #29215 (in 4.2) and the media library will show an error message when an upload fails in the modal. @Fab1en can you confirm?

Otherwise, the notifications API added in 4.6 as part of the setting validation improvements (#34893) provides the framework for controls to add notifications for errors, warnings, and informational messages.

[Fab1en]

Sorry for the late answer @westonruter, but I confirm that this issue is now irrelevant in WP 4.7. An error message is now displayed when a file cannot be uploaded during a customizer session.