New Rule: Report on and remove trailing slashes from links

[JoshuaKGoldberg]

Rule details

If a URL has a trailing link, e.g. www.google.com/, that trailing / is unnecessary and should be removed.

What type of rule is this?

Warns about a potential problem

Example code

https://www.google.com/
www.google.com/
google.com/

Prior Art

* https://github.com/vhf/remark-lint-no-url-trailing-slash
* https://github.com/xiaogaozi/markdownlint-rule-no-trailing-slash-in-links

Participation

• I am willing to submit a pull request to implement this rule.

Additional comments

This was originally requested in #228 by @DamianGlowala. Back then, this project was just a processor and did not have rules. It does now.

[mdjermanovic]

This would apply only to trailing slashes after the domain name? Not, for example, https://www.google.com/foo/.

[JoshuaKGoldberg]

Ah, good callout - I would want it to report on both cases. I don't recall ever seeing a meaningful distinction. AFAIK web browsers often treat with- and without-trailing-slashes as the same in many cases, both for after the domain name and after a path.

[mdjermanovic]

For trailing slashes after paths, web servers are usually configured to redirect one to the other, or to return the same result for both, but they're generally different URLs and can return different results, so I don't think they should be disallowed.

[JoshuaKGoldberg]

Do you have any examples of websites where they're treated differently? As in, after any redirects such as 301s, the end result page is different?

[mdjermanovic]

It would be difficult to find a real example, as it's a common practice to redirect, and a bit less common to treat them the same (return the same result without redirecting), but I made one:

https://mdjermanovic.github.io/test-site/foo/

https://mdjermanovic.github.io/test-site/foo

[mdjermanovic]

Also, even when the end result is the same, adding a trailing slash might avoid an unnecessary redirect.

[nzakas]

👎 I don't think this is specific enough to Markdown to be included (the same logic could be applied to links in any language). I also feel like the unpredictability of the behavior of removing slashes and the desire or not to have them create enough variables that this wouldn't be generally applicable.

As always, you can create a custom rule for this purpose if you so desire.

[snitin315]

I agree with @nzakas , I'm also 👎🏻 for this rule.