[inchang-ing]

Raw HTML blocks which start on a line indented by more than three spaces were not extracted by the HTML block preprocessor, as it could not distinguish such a start tag nested within a containing block (a list item, admonition, etc.) from an indented code block. The block parser then treated the HTML as inline content and split it into separate paragraphs at any blank lines within the raw block.

The preprocessor now extracts such indented raw blocks, removes the indentation of the start tag from the stashed content, and preserves that indentation on the line which holds the placeholder. The block parser can then make the decision based on the resulting block structure: within a containing block the placeholder is parsed as nested content, whereas an indented code block keeps the placeholder in its content. In the latter case, a RawHtmlInCodeTreeprocessor (running before the codehilite treeprocessor) restores the stashed HTML as escaped text, so indented code blocks are rendered exactly as before, whether or not codehilite is enabled.

Fixes #1096

Description

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  Specifically, Claude (Anthropic's LLM, via the WorkBuddy agent) was used to draft the code, tests, documentation, changelog entry, commit messages and this description. All output was reviewed, tested and verified by a human before submission.

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• This PR follows the contribution guidelines.
• The code follows the Code Style Guide.
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[waylan]

Please edit your initial comment and check the appropriate boxes (add a x in the brackets like this [x]).

[facelessuser]

I would like to see this tested with md_in_html as well. The testing seems generally sparse for such a potentially big change. I'd like to spend some time more thoroughly vetting this and seeing how it will impact 3rd party plugins as well.

[inchang-ing]

@facelessuser Good point — I've added TestIndentedHtmlBlockswMdInHTML to tests/test_syntax/extensions/test_md_in_html.py, which mirrors the two new regression cases with md_in_html enabled:

• test_indented_code_block_with_blank_lines — the indented block with blank lines still renders as a code block with the extension on (stashed HTML escaped in <pre><code>), identical to the default behavior.
• test_raw_indented_in_list_item — the raw block nested in the list item stays a single <div> inside the <li> rather than being split at blank lines.

Full suite: 1138 tests OK (111 skipped). Also checked the boxes in the PR template per @waylan's request.

[waylan]

You checked AI tools were used and I have disclosed which ones but I do not see where you have disclosed which ones.

[waylan]

I see you force pushed a change. As the Contributing Guide states:

It is generally best not to squash multiple commits and force-push your changes to a pull request. Instead, the maintainers would like to be able to follow the series of commits along with the discussion about those changes as they progress over time. If your pull request is accepted, it will be squashed at that time if deemed appropriate.

There have been multiple failures to follow our contributing guidelines. It is disrespectful for the reviewer's time. Please review the guidelines carefully and follow them fully going forward or this PR may be closed.

[inchang-ing]

Sorry about that — both fair points.

The AI disclosure is now filled in: Claude was used to draft the code, tests, docs, changelog entry, commit messages and the description; I reviewed and verified everything before submitting.

On the force push: understood, it won't happen again. The two fixes pushed since are regular incremental commits, and everything further will be as well.