I don't understand this "feature".

• Is the name attribute special here?
• If it's special: what does that imply?
• If it's not special: why mention this at all? If it's just like any other attribute, why mention this name attribute in particular?

Thanks!

The name attribute is not special itself. Actually, this tip indicates that you can use an attribute named name, which wasn't possible before 5.1. Also, this shows that if you need to add a name attribute on a tag, you must use a "special" syntax. Otherwise, the name attribute will be interpreted as the tag name, not as an attribute of it.

By doing

MailerSendmailTransport:
    tags:
        - { name: 'app.mail_transport', alias: 'sendmail' }

You declare a tag with the app.mail_transport name and an attribute called alias. This is a bit misleading because alias and name keys are at the same level. If you actually need an attribute called name, you must do the following:

MailerSmtpTransport:
    arguments: ['%mailer_host%']
        tags:
            - app.mail_transport: { name: 'arbitrary-value', alias: 'smtp' }

It took me some time to fully understand what this PR was all about 😄

By default, the name XML attribute contains the tag name, and so cannot be used to set an attribute named name. As of 5.1, there is a way to use name as an attribute by passing the tag name in the body of the XML element instead.

Thanks for your explanation. Now I can fully understand what's happening here. So, I've done some tweaks while merging to hopefully make it less confusing to readers: 6e6565b

Perfect! 🙂