[Regression?] Attributes extension not applied to `code` tag of code blocks

[cjbrooks12]

Describe the bug

In 0.42.12, attributes added with the Attributes Extension were applied to both the pre and code elements of code blocks. In 0.50.40, the same Markdown seems to only apply the attributes to the pre element, and I can't seem to find a way to get them applied to the inner code element.

This is a problem, as there is no way to apply additional attributes to code blocks in such a way that Javascript selectors can use them (such as for configuring a JS-based syntax highlighter). For example, the typical selector for finding code blocks of a particular language from Markdown is something like pre code[class='language-run-kotlin'], selecting the inner code element, but the configuration attributes are not available to the element that is selected.

• Parser
• HtmlRenderer
• Formatter
• FlexmarkHtmlParser
• DocxRenderer
• PdfConverterExtension
• Attributes extension (using default options)

To Reproduce

In 0.42.12, the following snippet would apply the attributes to both the

```run-kotlin
fun main() {
    println("Running from Kotlin Playground!")
}
```
{theme='darcula' lines='true'}

Expected behavior

Attributes are applied to both the pre and code elements, to be compatible with the 0.42.12 version. The following snippet is how the sample input above was rendered on 0.42.12.

<pre theme="darcula" lines="true"><code class="language-run-kotlin" theme="darcula" lines="true">fun main() {
   println(&quot;Running from Kotlin Playground!&quot;)
}
</code></pre>

Resulting Output

Attributes are only applied to the pre element, which is incompatible with 0.42.12. The following snippet is how the sample input above is rendered on 0.50.40.

<pre theme="darcula" lines="true"><code class="language-run-kotlin">fun main() {
    println(&quot;Running from Kotlin Playground!&quot;)
}
</code></pre>

[vsch]

@cjbrooks12, thank you for the catch.

Yes, I broke it by adding ability to add attributes after the info string for my plugin. vsch/idea-multimarkdown#760

I will add an option to generate it with attributes after info, by default to fall back to 0.42.12.

[vsch]

@cjbrooks12, as often happens, there is already a setting AttributesExtension.FENCED_CODE_INFO_ATTRIBUTES and it is set to true by default. I will change it to false in the next release.

As a workaround if you explicitly set AttributesExtension.FENCED_CODE_INFO_ATTRIBUTES to false in your parser/renderer options you will get old behaviour, which was to set attributes on the pre tag not code tag.

[cjbrooks12]

I think that option is different. It seems to change how attributes are parsed when they're in the first line of the code fence but doesn't change anything when the attributes list is immediately after the code fence. And it doesn't change whether or not the attributes are applied to the code tag within pre. To match the previous behavior, the parsed attributes should be applied to both the pre and code tags. Currently, they are only ever applied to pre.

[vsch]

@cjbrooks12, my bad. I did not realize that I "corrected" the fenced code attributes to only add them to the outer tag <pre>. This branch had no fenced code tests for attributes so I could not tell at a glance if I changed it. I added a test and saw the change.

I will fix it in 0.5.0 for backward compatibility and add an option to choose whether to add it to pre, code or both.

[vsch]

@cjbrooks12,
Fix for this is available. Repo updated branch 0.50, maven updated but may take a while to show up in maven central.

• Add: AttributesExtension.FENCED_CODE_ADD_ATTRIBUTES, default FencedCodeAddType.ADD_TO_PRE_CODE for backward compatibility with 0.42, but if this is option is not set and AttributesExtension.FENCED_CODE_INFO_ATTRIBUTES is set to true, default will change to FencedCodeAddType.ADD_TO_PRE since attributes after info are used to add to the code tag.

[cjbrooks12]

Just tried it out, it's working great. Thanks for the help!