Fix addresses convert function - compatibility with comma-separated emails

Thanks for the patch, however it's more complex than that. There can be a comma inside a display name.

Please see ✨ Add support for complex address strings in back-compatibility mode Active which this is a duplicate of.

@adamps
Nope, this is not the same one.
In #3350992 you are trying to fix the behavior for complex address strings there, but in general, the function MailerHelper::parseAddress() works already with comma-separated addresses, whereas the BaseEmailTrait::setAddress() function definitely does NOT, but should!

That issue can take a long time to resolve, whereas this fix is simple and necessary and can be applied more quickly.
It's just that when discussing that issue, you need to be aware that there may be more than one place with such a problem.

Ah thanks for explaining I understand now.

If you are using BaseEmailInterface::setAddress() then you should put each address in a separate array element. The function comment points to Address::convert() which says "Can be a single element or an array". It then refers on to Address:create() which says "string containing a single email address without display name".

So this is working as designed. You can put the explode into your calling code, or even better avoid joining with comma in the first place.