Emphasized URL with underscores

[p3k]

After upgrading marked from 0.3.3 to 0.3.4 I noticed a different output for the following call:

echo "_https://reddit.com/r/science/comments/5yde1e/its_official_time_crystals_are_a_new_state_of/_" | marked

This is was I got so far in marked 0.3.3 – which is also what I would expect:

https://reddit.com/r/science/comments/5yde1e/its_official_time_crystals_are_a_new_state_of/

<p><em><a href="https://reddit.com/r/science/comments/5yde1e/its_official_time_crystals_are_a_new_state_of/">https://reddit.com/r/science/comments/5yde1e/its_official_time_crystals_are_a_new_state_of/</a></em></p>

However, in marked 0.3.4 and greater the output becomes this:

_https://reddit.com/r/science/comments/5yde1e/its_official_time_crystals_are_a_new_state_of/_

<p>_<a href="https://reddit.com/r/science/comments/5yde1e/its_official_time_crystals_are_a_new_state_of/_">https://reddit.com/r/science/comments/5yde1e/its_official_time_crystals_are_a_new_state_of/_</a></p>

Please also note that Github’s markdown implementation behaves like 0.3.3:

https://reddit.com/r/science/comments/5yde1e/its_official_time_crystals_are_a_new_state_of/

[phiggins42]

came to file this same bug/regression. current test was @ 0.3.6 ... will move back to 0.3.3 it seems.

[joshbruce]

#984

[Feder1co5oave]

I'll just say that this is due to a change to the em inline rule:

@@ -454,7 +456,7 @@ var inline = {
   reflink: /^!?\[(inside)\]\s*\[([^\]]*)\]/,
   nolink: /^!?\[((?:\[[^\]]*\]|[^\[\]])*)\]/,
   strong: /^__([\s\S]+?)__(?!_)|^\*\*([\s\S]+?)\*\*(?!\*)/,
-  em: /^\b_((?:__|[\s\S])+?)_\b|^\*((?:\*\*|[\s\S])+?)\*(?!\*)/,
+  em: /^\b_((?:[^_]|__)+?)_\b|^\*((?:\*\*|[\s\S])+?)\*(?!\*)/,
   code: /^(`+)\s*([\s\S]*?[^`])\s*\1(?!`)/,
   br: /^ {2,}\n(?!\s*$)/,
   del: noop,

First of all, autolinking of plain URLs is GFM matter. Markdown (commonmark) allows autolinking of URIs wrapped inside <..>.
Still, even

_<https://reddit.com/r/science/comments/5yde1e/its_official_time_crystals_are_a_new_state_of/>_

gets parsed to

<p>_<a href="https://reddit.com/r/science/comments/5yde1e/its_official_time_crystals_are_a_new_state_of/">https://reddit.com/r/science/comments/5yde1e/its_official_time_crystals_are_a_new_state_of/</a>_</p>

and this is not correct. This is a tricky one.

Whenever underscores are present in URLs, it is advisable to use reflinks.

[Feder1co5oave]

@joshbruce I would re-open this one and put it under category 'emphasize'.

[joshbruce]

@Feder1co5oave: Re-opening. Putting under "links" for now. Would like avoid creating a category for individual HTML elements. That's why we have "lists" instead of "description lists", yeah?

Maybe inline and block would make sense as categories as well. I only created the initial categories because there were more than 5 or 6 issues revolving around that topic.

[UziTech]

this seems to be fixed in the latest version of marked. demo