react-markdown crushes if <li > element has spaces before it

[gilisho]

Subject of the issue

Issues with <li > element with a space at the beginning.
This is the problematic snippet:

  <li>hey
  
  </li>

Your environment

• Packages: react-markdown version 5 is affected. See in the live demo as well.

Steps to reproduce

remark: https://astexplorer.net/#/gist/19a843b97e350aaa80733876c81c1bed/60c88087318ea19410d99d798883b24a7733c520
react-markdown: https://codesandbox.io/s/react-markdown-debug-forked-o5rjw?file=/src/App.js

Expected behavior

What should happen?
This text:

  <li>hey
  
  </li>

Should be rendered like in Github:

hey

Actual behavior

App crushes when putting this text in react-markdown, as can be seen from the link.
Even when adding the gfm plugin, it does not parse like Github:
https://codesandbox.io/s/react-markdown-debug-forked-o5rjw?file=/src/App.js

[ChristianMurphy]

remark appears to be parsing as expected in https://astexplorer.net/#/gist/19a843b97e350aaa80733876c81c1bed/60c88087318ea19410d99d798883b24a7733c520
moving this to react-markdown.
In addition the issue appears to be a duplicate of #385 and #302

[ChristianMurphy]

This should be resolved by #427, in the meantime this is rendered as expected by react-remark https://github.com/remarkjs/react-remark (live demo: https://remarkjs.github.io/react-remark/?path=/story/remark-component--mixed-html-sanitized) which could be used as an alternative.
Closing as a duplicate, to follow along with progress, watch issues #385 and #302.

[gilisho]

Are you sure this is expected?

From the image above I thought remark parses it as two elements, which I think is an incorrect parsing.
and thanks!

[ChristianMurphy]

yes it is correct, from the CommonMark reference implementation https://spec.commonmark.org/dingus/?text=%20%20%3Cli%3Ehey%0A%20%20%0A%20%20%3C%2Fli%3E%0A

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE document SYSTEM "CommonMark.dtd">
<document xmlns="http://commonmark.org/xml/1.0">
  <html_block>  &lt;li&gt;hey</html_block>
  <html_block>  &lt;/li&gt;</html_block>
</document>

there are two HTML blocks, which matches the described spec as well https://spec.commonmark.org/0.29/#html-blocks