Add error logging and hooks to wp-cron.php

[Enchiridion]

Rarely and randomly some of my custom cron events have disappeared. From searching around, I'm not the only one with this issue, and no one else was able to figure out why. I also was unable to debug the issue since wp-cron.php doesn't log any errors nor have any hooks to try handling them. This patch adds those in.

[johnbillion]

Thanks for the ticket and the patch @Enchiridion.

Both the actions and the error logging make sense here and are a useful addition. I did think it would be beneficial to hook the calls to error_log() in via the actions, but it's additional overhead to introduce two new functions for this very narrow use case, so I think the direct calls to error_log() can suffice.

[costdev]

Patch updated to add translator comments, remove "or false" from docblocks, and revert two line removals.

[audrasjb]

The patch works fine on my side and looks good to go.

As today is beta 1 release date, I'll self assign this enhancement so it can be committed in time for 6.1 beta 1. @johnbillion feel free to ping me if you're actively working on this right now so I can reassign it to you :)

[audrasjb]

In 54258:

Cron API: Add error logging and hooks to wp-cron.php.

This changeset adds error logging on wp_reschedule_event() and wp_unschedule_event in wp-cron.php. This allows proper error logging when random errors appear. It also introduces cron_reschedule_event_error and cron_unschedule_event_error hooks which can be used to trigger additional behaviors when an error occurs.

Props Enchiridion, johnbillion, costdev.
Fixes #56048.