Lighthouse: Surface which line in robots.txt is blocking indexing

[russhuq]

CLI said the page is blocked for indexing but CDT said it isn't blocked, please see the video http://nimb.ws/oXGYa3.

[patrickhulce]

Thanks for the report and attached screencast @russhuq that really helps! ❤️

robots.txt files weren't checked until version 2.9.2 which is why you're seeing it pass in 2.8

[russhuq]

Thanks for the reply @patrickhulce!

Which specific robots.txt instruction is causing the page to get blocked would you guys consider adding this feature as well?

[patrickhulce]

@kdzwinel how difficult is it to add the blocking directive to the table like OP is wanting?

[kdzwinel]

Apparently @samclarke predicted that feature request, because he added getMatchingLineNumber in robots-parser v2.1.0 🎉 I'll be happy to implement it as soon as #4875 lands.