Retry-able emails should not include ones explicitly cancelled by plugin/modules

[bossanova808]

Description

We've started seeing a bunch of failed queue entries. The (erroneous) error reported is:

Email “Service Order to Ticket”, for order "cf5279c" was cancelled by plugin.

was cancelled by plugin is the important thing here...this is not an error, but a deliberate cancellation of the email. It's not the same as e.g. a template error in an email, and it should not be reported as an error at all.

To Reproduce

Have module code that cancels an email given some condition

Expected behaviour

Email should be silently cancelled (entry in a log file is ok, but an alarming looking failure message in the CP is over-doing it...)

Additional info

composer update-d all the things just now...

[pdaleramirez]

@bossanova808
The cause of this issue is that the event Emails::EVENT_BEFORE_SEND_MAIL got triggered and set to cancel an email. I would recommend scan all installed plugins and modules and check how it is being used. It should looks something like this

Event::on(
    Emails::class,
    Emails::EVENT_BEFORE_SEND_MAIL,
    function (MailEvent $event) {

        // Cancel email
        $event->isValid = false;
    }
);

[bossanova808]

@pdaleramirez Thanks - & yep I know what the cause is, as I wrote the module that does precisely that.

My point is - it's not an error, it's a deliberate use of a system to suppress emails, and until the very latest Commerce update, did not result in failure reports in the queue manager...and it should still not result in them....

[lukeholder]

@bossanova808 Fixed this for the next release. Plugins that use the event to stop the email being sent will no longer be shown as failed on the queue, just silently not sent. An error will still be logged that the email was prevented from being sent by a plugin.

[bossanova808]

Great, thanks Luke!