Bug: Importing from markdown does not respect escaping

[robfig]

Steps To Reproduce

1. Enter \*Hello\* here to see that it is valid markdown which is rendered as expected: https://spec.commonmark.org/dingus/
2. Go to lexical playground, clear the content, switch to Markdown mode. Enter \*Hello\*
3. Click the markdown button to import.

Expected: It populates the WYSIWYG editor with the literal text *Hello*

Actual: It displays \Hello\

This is because it ignores the escaping and treats the surrounding asterisks as a format to be applied. The process of applying the text formats should do a negative lookbehind assertion to confirm that the previous character is not a backslash.

Before import

After import

[robfig]

Oh interesting, createTextFormatTransformersIndex does indeed add a negative lookbehind for escaping. I'm not sure why it's not working at this point.

[robfig]

OK, it's the switch here that adds the negative assertion depending on userAgent. It turns out my Jest test is classified as IS_APPLE_WEBKIT (user agent "Mozilla/5.0 (linux) AppleWebKit/537.36 (KHTML, like Gecko) jsdom/20.0.3"), although I think it should support the regexp.

So maybe the fix is to change the condition under which it's not used?

    if (IS_SAFARI || IS_IOS || IS_APPLE_WEBKIT) {
      fullMatchRegExpByTag[tag] = new RegExp(
        `(${tagRegExp})(?![${tagRegExp}\\s])(.*?[^${tagRegExp}\\s])${tagRegExp}(?!${tagRegExp})`
      );
    } else {
      fullMatchRegExpByTag[tag] = new RegExp(
        `(?<![\\\\${tagRegExp}])(${tagRegExp})((\\\\${tagRegExp})?.*?[^${tagRegExp}\\s](\\\\${tagRegExp})?)((?<!\\\\)|(?<=\\\\\\\\))(${tagRegExp})(?![\\\\${tagRegExp}])`
      );
    }

[ratasorin]

Hello, I created a pull request that fixes this issue and #4808, you can see if it fits your requirements here: #4813

[antsorin]

Hi everyone.

Any update on this? Note that at the moment, neither import nor export handle the text content escaping, making the markdown support less reliable for production use.

Will @ratasorin's code be reviewed and hopefully merged soon?

[cduff]

Duplicate of https://github.com/facebook/lexical/issues/2715?