Hashtag link detection is inconsistent with web UI

[Tamschi]

Mastodon for Android requires the hashtag class on anchor elements to treat them as hashtag links: https://github.com/mastodon/mastodon-android/blob/9361c6d0dfcd1eb9d641f86219df6f5a86e44dac/mastodon/src/main/java/org/joinmastodon/android/ui/text/HtmlParser.java#L148-L153

The web interface does not (and also covers hashtag links with outer "#"): https://github.com/mastodon/mastodon/blob/67a8d4638c6e6a3ef178258504a6535746608c42/app/javascript/hooks/useLinks.ts#L13-L15

This occasionally causes trouble: https://github.com/snarfed/bridgy-fed/issues/1634#issuecomment-2577383556

It would be good to have parity here. Personally I'd prefer the behaviour of the web version, as I think I saw a post where the link didn't cover the "#".

[grishka]

Interesting, I had no idea the web app does any parsing of its own. I thought it just trusts what the server returns like I do. I've noticed that Friendica does the same thing with not including the # in the link. Just for reference, here's a Friendica post in the web app: Here's the same post in Smithereen (that doesn't support hashtags at all so treats them as links):

@Gargron what's your opinion on this? To me it feels like something that should be handled server-side.

[Tamschi]

@Gargron what's your opinion on this? To me it feels like something that should be handled server-side.

For what it's worth, I made a quick patch to achieve parity here.

I think it would be possible and helpful to overall match by href instead or additionally though, as that would additionally avoid compatibility issues with Mastodon's Unicode folding in hashtags.