Generated footnote html different from cmark-gfm

[digitalmoksha]

I've started doing some testing between comrak and cmark-gfm.

I've noticed that the footnote extension generates different html. In particular, data-footnote-ref, data-footnotes, data-footnote-backref, and aria-label attributes are no longer added.

input

1. one[^1]
[^1]: AbC

cmark-gfm output

<ol>
<li>one<sup class="footnote-ref"><a href="#fn-1" id="fnref-1" data-footnote-ref>1</a></sup></li>
</ol>
<section class="footnotes" data-footnotes>
<ol>
<li id="fn-1">
<p>AbC <a href="#fnref-1" class="footnote-backref" data-footnote-backref aria-label="Back to content">↩</a></p>
</li>
</ol>
</section>

comrak output

<ol>
<li>one<sup class="footnote-ref"><a href="#fn1" id="fnref1">1</a></sup></li>
</ol>
<section class="footnotes">
<ol>
<li id="fn1">
<p>AbC <a href="#fnref1" class="footnote-backref">↩</a></p>
</li>
</ol>
</section>

I also notice the footnote ids no longer use a -, such as fn-1 vs fn1

Are these changes by design, or missing implementation?

[digitalmoksha]

If it's missing implementation I can put together a PR, but if it's by design I won't worry about it.

[kivikakk]

Not by design — when first implemented it was 1:1, but it looks like GitHub have since added these attributes: github/cmark-gfm#234

Happy to accept PRs that realign.

[kivikakk]

With the merge of #273, we're a lot closer. There's a few smaller things:

• As @froh mentioned in does comrak allow spaces in footnote labels? cmark-gfm doesn't. #271, the footnote label content can differ. We should align this.
• As noted at Add footnote attributes that mirror cmark-gfm #273 (comment), there are some other differences in the IDs generated and the acceptable characters in labels. These should also be aligned. (This is currently causing spec failure in CI.)

[digitalmoksha]

Currently comrak sequentially numbers footnotes, while cmark-gfm utilizes the footnote name. For example:

first[^1] and second[^😄second] and twenty[^_twenty]

[^1]: one
[^😄second]: two
[^_twenty]: twenty

in comrak

<p>first<sup class="footnote-ref"><a href="#fn-1" id="fnref-1" data-footnote-ref>1</a></sup> and second<sup class="footnote-ref"><a href="#fn-2" id="fnref-2" data-footnote-ref>2</a></sup> and twenty[^_twenty]</p>
<section class="footnotes" data-footnotes>
<ol>
<li id="fn-1">
<p>one <a href="#fnref-1" class="footnote-backref" data-footnote-backref aria-label="Back to content">↩</a></p>
</li>
<li id="fn-2">
<p>two <a href="#fnref-2" class="footnote-backref" data-footnote-backref aria-label="Back to content">↩</a></p>
</li>
</ol>
</section>

and in cmark-gfm

<p>first<sup class="footnote-ref"><a href="#fn-1" id="fnref-1" data-footnote-ref>1</a></sup> and second<sup class="footnote-ref"><a href="#fn-%F0%9F%98%84second" id="fnref-%F0%9F%98%84second" data-footnote-ref>2</a></sup> and twenty<sup class="footnote-ref"><a href="#fn-_twenty" id="fnref-_twenty" data-footnote-ref>3</a></sup></p>
<section class="footnotes" data-footnotes>
<ol>
<li id="fn-1">
<p>one <a href="#fnref-1" class="footnote-backref" data-footnote-backref data-footnote-backref-idx="1" aria-label="Back to reference 1">↩</a></p>
</li>
<li id="fn-%F0%9F%98%84second">
<p>two <a href="#fnref-%F0%9F%98%84second" class="footnote-backref" data-footnote-backref data-footnote-backref-idx="2" aria-label="Back to reference 2">↩</a></p>
</li>
<li id="fn-_twenty">
<p>twenty <a href="#fnref-_twenty" class="footnote-backref" data-footnote-backref data-footnote-backref-idx="3" aria-label="Back to reference 3">↩</a></p>
</li>
</ol>
</section>

Will see if I can generate a fix.

[digitalmoksha]

I opened separate issues, #307 and #306.

I think we can close this one.