Correctly handle DB queries failing

[pento]

Nearly all “Save”-type actions in wp-admin don’t react correctly when the DB query fails - they show a success message, without confirming that the save occurred.

All screens and forms need to be audited for correct behaviour. If there’s a screen you want to grab, please comment in this ticket, then upload a patch when you're done.

[pento]

[30346] is how the post edit screen sanitizes data if the query fails, though it doesn't warn the user if the query fails a second time.

[azaozz]

What would be the "saving has failed" message and what action can we offer to the users so they can fix/try again?

Something like: "Saving failed. The text you've entered contains invalid characters. Please remove them and try again." won't make much sense unless we can somehow show/highlight the invalid chars. Not sure if that is even possible, if they are emoji on a Mac, they would look proper to the users.

[pento]

That's a pretty good point, we're better off removing the characters, so that users aren't required to dig through their changes to find the "invalid character".

I shall experiment a bit, and see what I come up with.

[pento]

In 31064:

Options: When updating options, make sure the user isn't trying to insert characters that aren't supported by the database character set.

See #30361.

[desrosj]

This appears to have been committed and included with WordPress 4.2.

I am closing this out as fixed. @pento please reopen if there still more parts to this.

[pento]

The initial idea was about providing feedback when the save failed, [31064] just strips invalid characters as a workaround.

I don't think it's going to get any further attention in a hurry, I'm fine with leaving it closed.