Unexpected syntax error when parsing a regexp with backslashes and special characters (new in 1.16.1)

[MatmaRex]

Hi, thank you for building this project, it's very useful!

After upgrading to Peast 1.16.1 to fix the edge case in parsing that @Krinkle reported in #67, we've discovered a new problem. It seems that the regexp parser that wasn't strict enough before is now too strict.

Minimal test case is: Peast\Peast::ES2016( '/=\n/' )->parse(); – this succeeds on 1.16.0 and throws an exception on 1.16.1.

Downstream bug reports for context, and links to the script that triggered the problem in case you need a bigger test case:

• https://phabricator.wikimedia.org/T358946 – https://pl.wikipedia.org/w/index.php?title=MediaWiki:Gadget-sk.js&action=edit&oldid=73032031
• https://phabricator.wikimedia.org/T359014 – https://en.wikipedia.org/w/index.php?title=MediaWiki:Gadget-XFDcloser-core.js&action=edit&oldid=1067165688

Thanks!

[mck89]

I've just fixed this bug and released a new version, actually the problem was only for a regex that started with /= since that is also an operator and the scanner could not detect when it should forgive an invalid character after that to try reconsuming it as regex.
Thank you for reporting!

[MatmaRex]

Thank you!