Markdown footnotes not working

Summary

Markdown footnote anchors are not working, both in the documentation as well as in issues, merge requests, etc. It seems that id attributes are missing. Here is a footnote as an example: ¹

Steps to reproduce

1. Visit the Markdown footnotes section in the documentation
2. Press the link for footnote no. 2
3. Nothing happens

You can also go to the bottom of the document and press the icon, nothing happens as well.

Expected behavior

Press the footnote link and the page should jump to the appropriate footnote.

Actual behavior

Nothing happens after pressing footnote links.

Output of checks

This bug happens on GitLab.com

1. Example footnote

mentioned in merge request !8439 (merged)

I have run into this as well, and it appears to be an issue with mis-named anchors in the footnotes?

Viewing the source, the footnote Markdown in the text looks like:

<a href="#fn3">3</a>

However, down in the footnote section, they have a different anchor:

<a href="#fnref3" rev="footnote">

I don't know if that's intentional, as I'm not a webdev, but they certainly don't appear to match.

@smcgivern when you have the time, can you please direct this to the right person?

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The footnote redirect from the footnote text to the footnote itself on https://docs.gitlab.com/ee/user/markdown.html seems to work now, but the link from the footnote to the footnote text seems to lead to a ">" at the end of the ToC. Is there already an official version where the footnotes are working? Our gitlab server doesn't seem to have a fix yet. :/

There seems to be an inconsistency where:

• here footnotes work: https://docs.gitlab.com/ee/user/markdown.html#footnotes
• here footnotes do not work: https://gitlab.com/help/user/markdown.md#footnotes

Even in https://docs.gitlab.com/ee/user/markdown.html#footnotes, the footnote just points to the table of contents?

Hello, everyone.

We are also running into this issue with documentation on our hosted CE instance.

From what I can gather, the issue is not wrong anchor tags, but missing id attributes.

This is how it looks on docs.gitlab.com under the Footnotes headline:

<p>
    You can add footnotes to your text as follows.
    <sup id="fnref1">
        <a href="#fn1" rel="footnote">1</a>
    </sup>
</p>

and the corresponding Footnote:

<li id="fn1">
    <p>
        This is my awesome footnote.&nbsp;
        <a href="#fnref1" rev="footnote">↩</a>
    </p>
</li>

And this is the broken code on the /help/ subpages on gitlab.com and hosted instances:

<p dir="auto">
    You can add footnotes to your text as follows.
    <sup>
        <a href="#fn1">1</a>
    </sup>
</p>

<li>
    <p>
        This is my awesome footnote.&nbsp;
        <a href="#fnref1" rev="footnote">
            <gl-emoji data-name="leftwards_arrow_with_hook" data-unicode-version="1.1">
                <img class="emoji" title=":leftwards_arrow_with_hook:" alt=":leftwards_arrow_with_hook:" src="/assets/emoji/leftwards_arrow_with_hook-504714c5559b1bd35aa469be83069a923d1a25f364cac08c10df0195749e7b26.png" width="20" height="20" align="absmiddle">
            </gl-emoji>
        </a>
    </p>
</li>

Note how the id attributes are missing, so the anchor tag cannot work.

---

Concerning the remark @ostrokach made about the footnote pointing to the toc. This seems to be an issue with the toc generation. For whatever reason the toc entry for the footnotes is generated differently than all other entries and actually contains the needed id attribute:

<li>
    <a href="#references">References</a>
    <div class="footnotes">
        <hr>
        <ol>

            <li id="fn1">
            </li>

        </ol>
    </div>
</li>

This may be because the source of markdown.html actually has an intentionally broken footnote url at the bottom.

---

To conclude:

• Footnote rendering works on pages.gitlab.com but not on any hosted CE/EE server.
• From what I understand pages.gitlab.com is pre-rendered using nanoc whereas hosted server docs are rendered on page view using lib/banzai.
• Both nanoc and lib/banzai are set to use redacrpet for markdown rendering:
  • nanoc: https://gitlab.com/gitlab-com/gitlab-docs/blob/master/Rules
  • lib/banzai: https://gitlab.com/gitlab-org/gitlab-ce/blob/master/lib/banzai/filter/markdown_filter.rb
• The issue concerning the broken link that @ostrokach posted may be unrelated, as the markdown contains a broken link. Though I would still mark this as a bug, albeit a separate one.

---

Hope this helps a bit!

Hello

We are also affected by this when browsing a project's files in GitLab: markdown files with footnotes are rendered incorrectly and behave as described above for the /help subpages: the id attribute is missing from both the note reference and the foot note itself, so that no link work.

This is visible in https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/user/markdown.md#footnotes for instance

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mentioned in merge request !14835 (merged)

marked #27797 (closed) as a duplicate of this issue

marked #3301 (closed) as a duplicate of this issue

marked #42620 (closed) as a duplicate of this issue

mentioned in issue #42620 (closed)

mentioned in issue #27797 (closed)

mentioned in issue #43011 (closed)

I just want to push this issue up. After one year, this bug is still there and effects both GitLab.com and CE.

We sanitize the html generated from user supplied markdown pretty thoroughly - this is stripping off the id attribute from the <li> tag that wraps the footnote.

We would either need to whitelist the id attribute (which I'm not sure is wise) or add the ids back in another step, like we do for header anchors.

@digitalmoksha I actually see few issues with whitelisting the id attribute unless they would conflict with existing id's. An alternative could be to prefix those id's instead of sanitizing them out completely.

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Customer is experiencing this issue (internal).

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Why do you need to sanitize HTML which comes from markdown? Isn’t the produced code known to be safe?

@MCMic actually the markdown processor itself doesn't do any sanitization - and markdown supports mixing markdown and html. So we have to sanitize on top of that.

assigned to @digitalmoksha

@jonas1 the ids can definitely conflict - each piece of markdown processed (such as each individual comment), the footnote id numbering starts over.

So if the issue has one footnote, it gets referenced with id="fnref1". If a comment also adds a footnote, it gets the same id, id="fnref1"

I think what we can do is add a random number to each footnote id. So the first one might be id="fnref1-1234567" and the second one might be id="fnref1-987651"

mentioned in merge request !24168 (merged)

created merge request !24168 (merged) to address this issue

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mentioned in merge request !24457 (closed)

closed via merge request !24168 (merged)

mentioned in commit ae0b8880

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