It is unclear how close a match a copyright must be to the "canonical pattern"

[thundernixon]

Observed behaviour

The valid_copyright check is written in such a way that suggests every copyright must match very closely. This seems (potentially) overly strict.

🔥 FAIL: Copyright notices match canonical pattern in METADATA.pb

• com.google.fonts/check/metadata/valid_copyright
• 🔥 FAIL METADATA.pb: Copyright notices should match a pattern similar to: 'Copyright 2017 The Familyname Project Authors (git url)'
  But instead we have got: 'Copyright 2012-2015 The Mozilla Foundation, Telefonica S.A., and Nikita Prokopov (https://github.com/tonsky/FiraCode)'

Expected behaviour

If there is some flexibility in what is acceptable in a copyright (e.g. multiple authors, multiple dates, etc), we should find a way to better indicate that. For example, the test could instead:

• Check for presence of the string copyright
• Check for presence of a year
• Check for presence of a GitHub URL
• Maybe check for author / project name(s)
• Maybe check for non-ASCII symbols (though this already happens in ascii_only_entries check)
• Otherwise, not get too hung up on formatting

I would also suggest that this might be more of a warn than a fail.

[vv-monsalve]

This would be the reasoning behind this apparent strictness in the formatting. From that, I think it is not only reasonable but also even necessary to stick to that.

[vv-monsalve]

But I would agree that the rationale could be improved to make that clear. I'll try to make a proposal, at this very moment I don't have the right mind for it :)

[tiroj]

Once one realises that The _____ Project Authors refers to the individuals or organisation identified in the accompanying AUTHORS.txt in the repo, the required form makes more sense. I was confused by the fail at first, but found this very helpful:
https://opensource.google/docs/releasing/authors/

[simoncozens]

We now have a good rationale text for this which explains the required components. As John says, because of Google's expectation for authorship/copyrights of open source property, the strictness here is desirable.