As specified by MAINTAIN.md, features should be soft deprecated at first
(meaning no warnings) to give people a chance to adjust. The problem
with this approach is that deprecating a feature becomes harder than
usual as during the soft deprecation period you need to remember not to
issue a warning, and during the hard deprecation period you need to
remember to start issuing a warning.
This behavior is only enforced if the `plugin` parameter is `nil` as
plugins may not want this specific behavior.
(cherry picked from commit 0a598c13b1)
3a535ff496