Relative canonical reported as invalid

[wasshuber]

Provide the steps to reproduce

1. Run LH on https://www.lybrary.com/the-royal-road-to-card-magic-p-35.html

What is the current behavior?

Reports canonical URL to be invalid because it is a relative URL.

What is the expected behavior?

The page defines a base URL with the <base> tag. This together with a relative URL in the <link rel=canonincal> tag defines unambiguously a complete/absolute URL as the canonical URL. This should not create an invalid response. It is completely standard conformant. The Google crawler correctly picks up this canonical URL without any issues.

Environment Information

• Affected Channels: DevTools
• Lighthouse version:
• Chrome version: 90.0.4430.93 (Official Build) (64-bit)
• Node.js version:
• Operating System:

Related issues

[patrickhulce]

Thanks for filing @wasshuber! Please see #12149 and the Google Search documentation on this subject. This audit isn't about what can work, it's about SEO best practices. If that's not a concern this site has, feel free to ignore this result then.

[wasshuber]

Thanks for the info. I guess my main problem here is the wording 'invalid'. 'Invalid' suggests that some syntax rule or official standard has been violated, which is not the case. Perhaps it should be called 'not recommended'.

[patrickhulce]

Yes, good point. Anyone watching interested in a good first bug to add "not recommended" to

lighthouse/lighthouse-core/audits/seo/canonical.js

Line 35 in a390c94

explanationRelative: 'Relative URL ({url})',

?
:)

[techguysid]

@patrickhulce I think I can take this up. Let me know if I should.

[patrickhulce]

sure @techguysid go for it! :)

[techguysid]

@patrickhulce - Thanks! Do you want me to replace invalid explanationInvalid: 'Invalid URL ({url})' to explanationNotRecommended: 'URL ({url}) not recommended' or add a new entry for it ?

[techguysid]

Because we would still be using explanationInvalid: 'Invalid URL ({url})' for some other cases if not this right? So I think adding new entry will help. Just wanted to double check.

[patrickhulce]

No, invalid URLs are still invalid. We're only tweaking the relative URL description to say it's not recommended

[techguysid]

Oh ok! explanationRelative: 'Relative URL ({url})' should have a not recommended thingy, something like explanationRelative: 'Relative URL ({url}) (not recommended)',

[techguysid]

@patrickhulce Here's the PR: #12479