Hashtag linking improvements

[mrvdb]

This improves rendering in a number of situations:

• it keeps anchor tags working
• it gives the user some control for not linking, for example in code
  blocks.

Con:
hashTags at the beginning of a line without a space won't get linked.

Workaround related to issues #42 and #6 and #33

[thebaer]

Thanks for trying to fix this. I agree this would solve some problems (especially for heavy users of same-page anchor tags), but breaking tags at the beginning of a line is too much of a regression to merge this. It also breaks tags that are put together without spaces around them, e.g. only 3 out of 8 tags correctly render in a post like this:

#test #lots #of #hashtags
#many#tags#every#where

I'm fine with suboptimal fixes sometimes, but especially since:

• it's currently possible to work around the in-page anchor issues, and
• this would introduce a visible bug that fails in these two very common cases,

I'd rather keep the current shortcomings until we have a fix for all scenarios mentioned in those issues.

[mrvdb]

Fair enough. Although, your second example line, is that really a common case?

The beginning of line failure is indeed a worry. I haven't really tried hard to get that into the regex, which could probably work, using the same method as getting the 'space case' to work.

For the generic case, having a working parser for a non-standardized format, as you mention 'we're not a markdown only shop', will be quite a challenge I think.

[mrvdb]

FYI I'm keeping a test page up here for myself which has the changes in this branch: https://qua.name/debug/test-for-hashlink

[thebaer]

Sorry I dropped off the map on this one. I agree the second case isn't common, but I'd like to support it, as I think it's expected behavior for anyone coming from other social networks, like Instagram.

I appreciate you taking the time on this. It's a good temporary fix, but as this will be deployed in an attempt to fix the issue for all WF users, including 40k+ users on Write.as, I'd really like to implement a permanent fix, likely involving changes to the saturday parser similar to the ones mentioned in #6. I believe it'll be straightforward, especially after figuring out how the parser works. So I'm gonna try to get to it this week.

[thebaer]

Issues should be fixed with changes to the Markdown parser, where it's aware of when a "hashtag" is inside a href attribute or code block.

[mrvdb]

No worries. I wanted to have the temporary fixes published somewhere so other instances could choose to patch theirs if they wanted to. I fully agree the permanent fix needs to be different.
Wouldn't it help if we were coding against a markdown standard like https://commonmark.org or is that a bridge too far?

[thebaer]

I don't know that it'd help, since we'll have to extend the standard no matter what. Or is there some other way you were thinking it'd help out?

Either way, I could see the case for adding the option between a standard like commonmark or our restricted flavor of Markdown in the future.

[mrvdb]

I was indeed advocating conforming to *a* standard indeed; commonmark seemed the most sensible.

If that needs to be in the form of an option for compatibility reasons, that is fine obviously

[thebaer]

Yeah, I want to support users who just want to write in plain text, and I think the current library is a decent tradeoff between supporting that and basic Markdown without requiring any explicit customization.

But I've added this as a new task: T557

[thebaer]

I'm going to take another crack at the parser-based fix this coming week, but if I'm not able to make progress, I'll merge this in. Since this fixes so many different issues, and hashtags at the beginning of a line work, I think this will be a good solution.

[thebaer]

Merging now -- thanks again!

Closes #33, closes #42