[9.x] Unable to queue Mailable if using priority

[giggsey]

• Laravel Version: 9.0.1 (I think I saw this in 8.x too, but didn't investigate)
• PHP Version: 8.0.14

Description:

If your Mailable has a priority (assuming the bug in #40916 has been fixed), then the message will fail to queue with:

Serialization of 'Closure' is not allowed

This is because the priority setting is done through a callback within Mailable.

Steps To Reproduce:

class MyTestEmail extends Mailable implements ShouldQueue {
    public function __construct() {
        $this->priority(1);
    }
}

\Mail::to('[email protected]')->queue(new MyTestEmail());

[giggsey]

Moving priority() into the build function instead of the constructor works enough as a workaround, so maybe that's fine.

[driesvints]

Yes please move this to the build method. Thanks