Cursive attachment easily broken

I notice that the current version (including the latest stable 3260) fails to export Arabic font with cursive attachment + kerning. The “kerning” is achieved by sneaking elevation-checker glyphs (set as non-spacing marks), and implemented in a couple of retails fonts I’ve done.

スクリーンショット 2024-08-07 19.23.08

The latest Glyphs seems to handle mark feature differently, and prevent letters from connecting when the mark glyphs are present. How can I fix this?

can you check the curs code? What is the category/subcategory of those marker glyphs? They need to be marked as none spacing marks.

Their custom glyph info are Arabic, Mark, Nonspacing (maybe I should add RTL? it makes no difference though).
The curs code looks fine, nothing jumps out as odd.

Was there a version that exported this correctly?

Yes to my knowledge, at leas back in Feb 2023. A retail source file at the time fails in cursive attachment.

I think this is the same issue as GDEF classes are not set for glyphs without anchors

True. I looked into this last night. Hopefully I can fix this, soon.

Yup, seems like the same issue.

How soon do you think, like ‘next build’ soon?

I’m in a middle of teaching OpenType Ruqah, and my lesson can change depending on how Glyphs handle the issue at the moment.

Update is up.

Thanks, it’s working!