Link redos

[UziTech]

Marked version: master

Description

Fixes redos when code blocks are in square brackets that are not links.

• FixesRegular expression backtracking in linkification #1425

Contributor

• Test(s) exist to ensure functionality and minimize regression (if no tests added, list tests covering this PR)

Committer

In most cases, this should be a different person than the contributor.

• Draft GitHub release notes have been updated.
• CI is green (no forced merge required).
• Merge PR

[UziTech]

/cc @Feder1co5oave@davisjam

I'm not sure this is a great fix. The test still takes a few hundred milliseconds.

[Feder1co5oave]

I tried a different approach but this seems better! It's far from perfect though. I think this issue is inherent in the way links and code spans bind.

So, for example:

[foo`](url)` <-- this is not a link
[`foo]`](url) <-- neither is this
[foo`](url) <-- but this is
[foo`](url)`` code `` <-- and this too.
[foo`](url)``code` <-- these are just two code spans sitting back-to-back

Whenever we try to match a link, if we find a ` inside the text part, we cannot know if it is a lonely backtick, the start of a codespan contained within the link text, or the start of a codespan which invalidates the link-like part we matched up at that point.
Also, code spans by themselves are hard to parse!:

marked/lib/marked.js

Line 546 in c679e5e

code: /^(`+)([^`]|[^`][\s\S]*?[^`])\1(?!`)/,

I think we should consider trying to resemble the codespan matching regex to avoid backtracking too much. Something along the lines of (`+) ... \2...

If you want to merge this fix in the mean time, that's fine too!

[styfle]

Looks good, besides adding butt to the repo 😆