Issues with non-breaking space and non-standard end of line

[mgajda]

Explain the problem.

Users will increasingly use non-breaking space and non-CRLF end of line characters.

These are currently breaking Markdown syntax.

For example this apparently valid pair of chapters is parsed as a single heading, and then a paragraph:

# Good chapter

# Bad chapter

This is because there is non-breaking space after # and before "Bad chapter".

The produced output in Try Pandoc from Markdown to HTML:

<h1 id="good-chapter">Good chapter</h1>
<p># Bad chapter</p>

Same issue may occur when creating a list.

We propose to patch detection of Markdown syntax, so that any space is treated as a space, and any line breaking combination (either CRLF and plain CR) is treated as end-of-line within Markdown syntax.

Pandoc version?

Pandoc 3.2.1 in https://pandoc.org/try, with arguments: pandoc --from markdown --to html5 --no-highlight.

[jgm]

I think it makes sense to require a standard space after #. I'm not sure why someone would insert a nonbreaking space there.