fix: terminate the build process when font resolution fails

[cernymatej]

🔗 Linked issue

resolves #356

❓ Type of change

• [ ] 📖 Documentation (updates to the documentation or readme)
• [ ] 🐞 Bug fix (a non-breaking change that fixes an issue)
• [x] 👌 Enhancement (improving an existing functionality)
• [ ] ✨ New feature (a non-breaking change that adds functionality)
• [ ] 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• [ ] ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

This will ensure that the build process is terminated when the font face declarations cannot be produced, preventing a project with broken fonts from being deployed.

---

I'm wondering if this should be addressed upstream in unifont as well. https://github.com/unjs/unifont/blob/f4d3efae764b78ab4c11cf303e465ecf5b95c1a4/src/index.ts#L55-L57 https://github.com/unjs/unifont/blob/f4d3efae764b78ab4c11cf303e465ecf5b95c1a4/src/index.ts#L79-L81

However, that would likely require a major version bump since it would be a breaking change. Then again, it might not be necessary, as one could simply check the return value to determine whether the resolution was successful.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 82.73%. Comparing base (33e98b0) to head (b81a658).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #518      +/-   ##
==========================================
- Coverage   82.84%   82.73%   -0.11%     
==========================================
  Files          13       13              
  Lines        1067     1066       -1     
  Branches      264      268       +4     
==========================================
- Hits          884      882       -2     
- Misses        178      179       +1     
  Partials        5        5              

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[danielroe]

It's possible that nuxt/fonts might process something that isn't a valid font (and therefore can't resolve it).

So I think the scenarios we should care about are:

• if the font providers can't initialise their registries
• if the font providers don't provide font data even though they have the font in their registry
• if we can't download the fonts

[cernymatej]

Could you please share an example of a case where something fails to resolve, but we wouldn’t want to throw an error here? 🙏 I'd like to test it.

The resolveFont function from unifont receives a fontFamily parameter, so I assumed it was already considered a valid font face.
https://github.com/nuxt/fonts/blob/6632fa2f2378af20d94ab87b37979708c4adc5ee/src/module.ts#L211

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Are you suggesting that we should throw an error when a failure occurs in these places instead?

Downloading registries https://github.com/unjs/unifont/blob/f4d3efae764b78ab4c11cf303e465ecf5b95c1a4/src/index.ts#L51

Downloading font details https://github.com/unjs/unifont/blob/f4d3efae764b78ab4c11cf303e465ecf5b95c1a4/src/index.ts#L71

Downloading fonts https://github.com/nuxt/fonts/blob/6632fa2f2378af20d94ab87b37979708c4adc5ee/src/assets.ts#L153 (probably unnecessary, since errors aren’t caught here anyway - we can keep the fetch error, if it occurs)

[danielroe]

It might fail - I think - if the font family isn't a web font or if it's processing a css variable which doesn't have a font family.

[danielroe]

we can use https://github.com/unjs/unifont/pull/161 once the next release of unifont