Code chunks accessibility issue "Link missing a text alternative"

[josenino95]

This is my final issue on accessibility, related to #190 and #191.

The SiteImprove tool identified that code chunks weirdly generate hyperlinks that don't have alt text.

For example, looking at the HTML source of the Git SW lesson (right now it's line 443 of the HTML source) for an example with the Git SW lesson. Here an <a ...> tag is created, href="#cb2-1", but there isn't actual text inside between <a></a>. So that's why the accessibility tool is flagging it.

<pre class="sourceCode bash" tabindex="0"><code class="sourceCode bash"><span id="cb2-1"><a href="[#cb2-1](https://swcarpentry.github.io/git-novice/04-changes.html#cb2-1)" tabindex="-1"></a><span class="ex">$</span> nano guacamole.md</span></code></pre>

Do you know the reason why code chunks create these <a> tags? After a quick review, I see this happening to Shell and Python chunks, but not R or Output chunks.

[ndporter]

My understanding is that this is not as big of an accessibility problem. There are hyperlinks to enable in-page linking (or deep linking from outside) but they're not meant to be clickable in the same sense because they literally just return you to the chunk of the page where you clicked it.

[froggleston]

Hey @josenino95 - can you link to the HTML source please (or the episode/section of the git-novice lesson)? I can't seem to find the cb2-1 example you show.

Ah - I see it now - the bash chunks. That will be tricky to implement, unless we use something like bash-code-chunk-1 ?

Update: after more digging, this is "controlled" by pandoc, so isn't immediately resolvable: https://stackoverflow.com/questions/79875420/pandoc-converting-md-to-html-wcag-uncompliant-links-in-code-blocks

[josenino95]

I just edited my issue description to make it clearer, and I noticed the markdown syntax []() doesn't let me link the HTML source, but here it is: view-source:https://swcarpentry.github.io/git-novice/04-changes.html.

But is there a reason why those links are generated for bash but not for output? I don't see how it can be useful to have these sort of #cb2-1 in-page linking as that the user can actually use.

[froggleston]

Yes, pandoc only creates the id element for pre elements (the three backtick blocks) with a language specified. I'm looking into the possibility of using the lesson.lua in sandpaper to adjust these.

@josenino95 Could you please paste the output of the SiteImprove tool for this particular problem? I can't seem to use the SiteImprove tool without some kind of login or subscription, so I'm going on this site (which does also highlight this problem): https://www.accessibilitychecker.org/audit/?website=https%3A%2F%2Fswcarpentry.github.io%2Fr-novice-inflammation%2F&flag=us

[josenino95]

SiteImprove does require a login. Try with this link please (it's specific for that "Tracking Changes" episode of the Git lesson, but our own fork of the lesson): https://my2.siteimprove.com/Inspector/1237935/A11Y/Page?PageId=343679463744&impmd=A74FC28FD5FAD95A0E08DD9E49865810&issue=cantTell+failed&conf=a+aa+aria+si#/sia-r11/failed/eXpkQW5LakQ=;ZDEwNTVmOTU=

If that link doesn't work, I'm pasting next what it shows me, as I don't see a better way to export the report.

Details

Issue
Link missing a text alternative
Issue
2.4.4: Link Purpose (In Context)
2.4.9: Link Purpose (Link Only)
4.1.2: Name, Role, Value
Links should always have a text alternative. The link text can be inserted into the HTML — it does not need to be visible to pass this check.

Why is this an issue?
Links represented by images or icons can be problematic for visitors who are blind or have low vision.

The text alternative should describe the link's purpose — or what visitors can expect to find after they click it.

Help Center: Link without a text alternative, explained
WCAG 2.2: Understanding Success Criterion 2.4.4: Link Purpose in Context
WCAG 2.2: Understanding Success Criterion 2.4.9: Link Purpose (Link Only)
WCAG 2.2: Understanding Success Criterion 4.1.2: Name, Role, Value
Siteimprove Alfa: Technical documentation for rule SIA-R11

Occurrences
45
Decision

No decision taken
45

Dismissed as can't fix 0

Dismissed as false positive 0

Occurrence details:carpentry.library.ucsb.ed...ice/04-changes.html#cb1-1
Provide a text alternative for the link.

Occurrence details:carpentry.library.ucsb.ed...ice/04-changes.html#cb2-1
Provide a text alternative for the link.

Occurrence details:carpentry.library.ucsb.ed...ice/04-changes.html#cb9-1
Provide a text alternative for the link.

Occurrence details:carpentry.library.ucsb.ed...ce/04-changes.html#cb11-1
Provide a text alternative for the link.

Occurrence details:carpentry.library.ucsb.ed...ce/04-changes.html#cb13-1
Provide a text alternative for the link.

Occurrence details:carpentry.library.ucsb.ed...ce/04-changes.html#cb15-1
Provide a text alternative for the link.

Occurrence details:carpentry.library.ucsb.ed...ce/04-changes.html#cb16-1
Provide a text alternative for the link.

Occurrence details:carpentry.library.ucsb.ed...ce/04-changes.html#cb18-1
Provide a text alternative for the link.

Occurrence details:carpentry.library.ucsb.ed...ce/04-changes.html#cb20-1
Provide a text alternative for the link.

Occurrence details:carpentry.library.ucsb.ed...ce/04-changes.html#cb22-1

[froggleston]

Resolved in carpentries/sandpaper#716