Beginnings of a designspace profile

[simoncozens]

Description

This implements the following consistency checks on a .designspace file:

• com.google.fonts/check/designspace_has_sources: Check that all sources in a designspace can be loaded successfully.
• com.google.fonts/check/designspace_has_default_master: Check that a default master is defined.
• com.google.fonts/check/designspace_has_consistent_glyphset: Check that non-default masters do not contain glyphs not found in the default master.
• com.google.fonts/check/designspace_has_consistent_unicodes: Check that Unicode assignments are consistent between masters.

To Do

• update CHANGELOG.md
• wait for all checks to pass
• request a review

[felipesanches]

In general I prefer to avoid creating new profiles. Things should fit some of the existing profiles such as universal or googlefonts.

This one though, as well as the ufo one, operate on source files of a font project so it makes sense for them to be separate. On the other hand, maybe we should merge all source-level profiles into a single one. Or even better, mirror the binary-check profiles nomenclature. Something like universal-src, googlefonts-src, etc.

In the future we might even make the profiles smart to distinguish whether source or binary checks should be performed, based on the types of files provided on the command line.

[felipesanches]

Here I'm just expressing how I feel about this matter in terms of a long-term project vision. I've considered other ways people have tried to deal with creation of new profiles in past PRs and it seems to me that indiscriminate creation of many new profiles for the purpose of grouping checks while not including them as child-profiles under one of the existing vendor-specific or universal ones will potentially just lead to important checks being segregated / forgotten.

[simoncozens]

I think I'm going to open a new issue to discuss how to handle non-TTFs in profiles: #3169

[m4rc1e]

I personally don't mind individual profiles for every source type if the checks are useful to all vendors. I can see this profile being used by everyone, not just us at Google Fonts.

[m4rc1e]

I guess if we needed our own designspace profile, we could create check-googlefonts-designspace which inherits from this profile. My worry is by including designspace stuff in the other profiles, we may create even more spaghetti than we're trying to eliminate.

[simoncozens]

I agree that this should go in check-universal and its checks should be picked up there if we are handed a designspace file. In #3169, I mentioned some things we will need to clear up make that happen.

[felipesanches]

Have you seen this? https://github.com/LettError/DesignspaceProblems

[felipesanches]

@simoncozens, do you plan on resuming efforts related to this PR? Such as integrating these checks into either googlefonts or universal profile?

[simoncozens]

At some point, yes. But I have to make sure that we can happily throw .designspace files at fontbakery and have them dispatched to checks with the appropriate conditions. (See #3169)

That might already work, I just haven't tried it!

[felipesanches]

hey, @simoncozens, as you told us you're on a "fontbakery hacking mood" this week, this could be a good PR to review

[felipesanches]

Work on this continues at #3448