A bug was reported in Discourse’s Oneboxing URLs with two dashes. danekhollas found that URLs containing -- would be converted incorrectly. A workaround was suggested by sam using <https://cs--preview.khanacademy.org>. However, this method prevents oneboxing.
codinghorror questioned the necessity of having two dashes in the URL, but danekhollas argued that Discourse should handle valid URLs correctly.
After discussing possible solutions, including using HTML entity escaping or adding a space in front of the URL to prevent oneboxing, Vitaly reported that the issue was solved in the linkifier and auto-propagated to markdown-it after a dependencies upgrade. A test URL http://cs--preview.khanacademy.org now works correctly, and the issue can be marked as solved.
Ok, here’s a weird bug. When an URL contains --, the markdown converts it do –
For example, this URL: cs--preview.khanacademy.org
If I explicitly insert a link, it works, even though it is rendered incorectly:
[https://cs--preview.khanacademy.org](https://cs--preview.khanacademy.org)
https://cs–preview.khanacademy.org
PS: Hm, linkifying seems to be disabled here on meta, but hopefully the second example makes things clear.
Having two dashes in the URL is quite unusual. Do you need to do that? Why doesn’t a single dash suffice?
Well, I do not know, but I do not control how the URL looks. 
I’d say if it is a valid URL, Discourse should handle it correctly, no?
I do think it is a minor bug in linkify / prettify interaction, @Vitaly is this an edge case we should report?
@danekhollas a workaround is to do <https://cs--preview.khanacademy.org> https://cs--preview.khanacademy.org which bypasses all magic.
That works but also prevents oneboxing.
There is an edge case here where we should onebox
<https://example.com>
On a line by itself
<> though is already the escape hatch from inline onebox so this would give it double meaning, it is edge case on top of edge case. Tricky problem, not sure there is trivial solution here. prettify though should ideally apply after linkify not before it, we can fix that.
I guess… the escape from one boxing is also to add a space in front of the URL. I have run into other cases like this on BBS so it is a real problem. I had to use HTML entity escaping to get around it which is even worse.
Sorry, I mean for example: https://unsplash.com/collections/411759/awesome-pictures will become https://unsplash.com/collections/411759/awesome-pictures so the escape hatch is: <https://unsplash.com/collections/411759/awesome-pictures> if you need it or a raw link without inline onebox.
So that means we turn <> into
It kind of has a double meaning, since it is mega ninja territory I guess we can live with it.
I am ok to make this change I guess.
This also raises the question of how do we “force opt-in” an inline onebox which I guess mean punycode url for now.
I am only referring to full size one boxes
See Onebox all the links! - #99 by Wanderfound - meta - Boing Boing BBS
I guess, “two-dashes” issue was solved in linkifier linkify-it/CHANGELOG.md at master · markdown-it/linkify-it · GitHub, and auto-propagated to markdown-it.
So, fix was landed to discourse after dependencies uprgade. Proof:
test http://cs--preview.khanacademy.org test
I think, this can be marked as solved. No more <...> scopes required for this kind of links.