In general, we have an issue now where email addresses can get shadowed. For example, if you have a user named `bugs` and also configure a `bugs@` address, both will accept mail sent to `bugs@`.
Currently, this will throw an exception which does not have many details about why the collision is occurring. See <https://github.com/facebook/phabricator/issues/480>.
I think we should probably pursue a two-part solution to this:
- Improve the error message so it shows which receivers were willing to accept the mail, and why.
- Provide a non-colliding disambiguation address for users, like `user+bugs@...`, and mention it in the exception.
Also, possibly, we should:
- Raise a setup error for all user-configured email addresses if more than one receiver accepts them? Specifically, when you configure a mailing address for `bugs@`, we can resolve a fake mail and see if it hits more than one receiver, then let you know you've shadowed something.