veraPDF (GreenField) fails to parse font opened correctly by PDF vievers, FontForge, freetype

[ceztko]

The attached file below produces the error "Can't parse font program of font" with veraPDF 1.27.102 GreenField (latest dev). VeraPdf obviously produce a failed PDF/A-1 report because of this problem. The document has been shrank to include only the failing part of the original content. The font is a subset of a CFF based font that was produced with the library components of afdko (I can provide the original font, if required). The subset opens correctly in PDF viewers, FontForge and the freetype library. I'm also attaching the extracted CFF font and the veraPDF report.

FontParseFailure.pdf
FontAndReport.zip

[bdoubrov]

@ceztko it looks like veraPDF CFF parser is confused by the Name INDEX of the embedded CFF font (see Adobe Technical Note #5176, Section 7) that is supposed to store the PostScript name(s) of the font. In your case it just contains a zero length string.

I note that Adobe Preflight tool also gives this as a warning when inspecting this font:

We'll fix this case by also logging this as a warning and trying to parse the font further. I do agree this doesn't seem to be a critical parser error.

[ceztko]

Thank you. The original font as you can imagine is 3rd party and it's manipulated by a reliable Adobe open source tool (afdko) which is probably just preserving the original content and performing as little validations as necessary. I am happy GreenField is being fixed to accept such fonts.

[MaximPlusov]

Fixed in the latest dev build 1.27.108