[opentype/name/match_familyname_fullfont] Unclear rationale, unsure whether fail is warranted

[arrowtype]

Observed behaviour

I’m building binary fonts directly from UFO sources, using FontMake.

As part of this, ufo2ft will construct NameID 4 from the same UFO info fields that are used to set up NameIDs 16 & 17.

https://github.com/googlefonts/ufo2ft/blob/5a606b7884bb6da594e3cc56a169e5c3d5fa267c/Lib/ufo2ft/outlineCompiler.py#L402-L435

The problem is, there is a Font Bakery check which will yield a FAIL if NameID 4 doesn’t start with NameID 1: match_familyname_fullfont.

However, the rationale of this check is slightly ambiguous. Can NameID 4 start with any of the three listed names, or only NameID 1?

• Based on the rationale, I would guess the first thing is true (NameID 4 can start with NameID 1, 16, or 22), but...
• Based on the check results, it seems that the much stricter match is true (NameID 4 must start with exactly NameID 1)

The FULL_FONT_NAME entry in the ‘name’ table should start with the same string as the Family Name (FONT_FAMILY_NAME, TYPOGRAPHIC_FAMILY_NAME or WWS_FAMILY_NAME).

If the Family Name is not included as the first part of the Full Font Name, and the user embeds the font in a document using a Microsoft Office app, the app will fail to render the font when it opens the document again.

Is it known which scenario is true?

Related issues:

• [com.google.fonts/check/name/match_familyname_fullfont] possible false positive with legacy name ID 1/2 #4190
• Checks name/fullfontname, name/postscriptname and name/match_familyname_fullfont falsely reject abbreviated font names #2254

Expected behaviour

I would expect one of the following:

• If NameID 4 can start with NameID 1, 16, or 22, then ufo2ft is working well, and this check should be made less strict.
• If NameID 4 must start with exactly NameID 1, then ufo2ft should be adjusted to set NameID 4 based on the styleMap names (Names 1 & 2), instead of the preferred typographic names (Names 16 & 17).

Resources and steps needed to reproduce

I can’t share the fonts publicly, but I can share them directly via email, if a reproduction case is necessary.

Thank you!