Mastodon normalizes URIs in the status by using Addressable, to NFKC.

https://github.com/tootsuite/mastodon/blob/85c7c42098b5a5b10033eb8de79f6cb5dce8d462/app/lib/formatter.rb#L102-L109

Well, what if the linked website has unnormalized URI? The link will be broken if we normalize it.

For example, we can't link this article in the toots (and it can be posted to Twitter and Facebook):

http://katsu2000x.hatenablog.com/entry/2017/03/17/android%E3%81%A7%E9%80%9A%E7%9F%A5%E3%81%8C%E6%9D%A5%E3%81%AA%E3%81%84%E4%BA%8B%E8%B1%A1%E3%82%92%E5%9B%9E%E9%81%BF%E3%81%99%E3%82%8B%EF%BC%88IPv6%E7%B7%A8%EF%BC%89_

Also I don't know why we need to normalize non user-input URIs, like hub_topic.

Looks like RFC3987 mentioned this problem in sec. 5.3.2.2.

• I searched or browsed the repo’s other issues to ensure this is not a duplicate.
• This bug happens on a tagged release and not on master (If you're a user, don't worry about this).