[naaz234]

Description

FencedBlockPreprocessor.run passes every key/value pair from a fenced block's attribute list on to CodeHilite, including pygments_formatter, so one block can replace the formatter set in the codehilite configuration. With Pygments installed and just fenced_code and codehilite enabled:

>>> import markdown
>>> markdown.markdown("``` { .text pygments_formatter='text' }\n<b>Some HTML</b>\n```", extensions=['fenced_code', 'codehilite'])
'<p><b>Some HTML</b>\n</p>'

Pygments' text formatter writes the code out as is, so the content of that block is not escaped the way it is in every other code block. Other formatters don't give HTML at all (pygments_formatter='raw' renders a b"..." bytes repr). The fenced code docs list HtmlFormatter and lexer options as what a block can set, and pygments_formatter is neither.

The key is now dropped from the attribute list's settings before they are merged with the codehilite configuration, which is similar to CodeHilite always forcing full off. This only affects the Pygments branch. Without Pygments, the key is still written as a <code> attribute (with attr_list) as before, and other per-block options such as linenums, css_class and use_pygments work as before.

The new test sits with the other per-block option tests. It fails on master with Pygments 2.7.1 and passes with this change. The full suite passes with Pygments 2.7.1 and without Pygments, and flake8 is clean.

AI Assistance Disclosure

• No AI tools were used in preparing this PR.

• AI tools were used and I have disclosed which ones, and have fully reviewed and verified their output.

  AI tools were use to assist with the following:

  • Code
  • Code Comments
  • Documentation
  • Changelog Entry
  • Commit Message
  • The Description Above
  • Other: finding the issue, the test, and the reproduction above

  Tool used: Claude Code (Claude Opus 5.5).

Checklist

• This PR follows the contribution guidelines.
• The code follows the Code Style Guide.
• The commit message follows the Commit Message Style Guide.
• I have added or updated relevant docs, including release notes if applicable which follow the Documentation Style Guide.
• I have added or updated relevant tests.
• I have not requested, and will not request, an automated AI review for this PR.

[waylan]

I'm not sure why we care about this. This seems like a situation of garbage in, garbage out.

[naaz234]

Fair point. The reason I thought it was worth it is that, as far as I can tell, pygments_formatter is the only key a block can set that switches off the escaping every other code block gets, and the docs only list HtmlFormatter and lexer options as settable per block, so it looked like it had slipped through rather than being intended. That said, it does need the author to ask for that formatter explicitly, so I take the garbage in, garbage out point. Happy to close this if you don't think it's worth carrying.