makeOTF error: mark

Hello,

After having rebuilt Cyrillic glyphs as components of Latin glyphs, I am getting an error when I export fonts: ‘script behavior already specified (text was “latn”) in mark’

mark is:
feature mark {
lookup markcyrl {
pos base [A-cy] <anchor 316 0> mark @mark_bottom <anchor 326 644> mark @mark_top;
pos base [Es-cy] <anchor 310 0> mark @mark_bottom <anchor 346 644> mark @mark_top;
pos base [Te-cy] <anchor 284 0> mark @mark_bottom;
pos base [Dze-cy] <anchor 224 0> mark @mark_bottom;

} markcyrl;
lookup marklatn {
pos base [A] <anchor 316 0> mark @mark_bottom <anchor 326 644> mark @mark_top;
pos base [C] <anchor 310 0> mark @mark_bottom <anchor 346 644> mark @mark_top;
pos base [G] <anchor 338 0> mark @mark_bottom;
pos base [K] <anchor 271 0> mark @mark_bottom;
pos base [L] <anchor 244 0> mark @mark_bottom;
pos base [N] <anchor 324 0> mark @mark_bottom;
pos base [R] <anchor 269 0> mark @mark_bottom;
pos base [S] <anchor 224 0> mark @mark_bottom;
pos base [T] <anchor 284 0> mark @mark_bottom;
pos base [Agrave] <anchor 316 0> mark @mark_bottom <anchor 326 644> mark @mark_top;
pos base [Aacute] <anchor 316 0> mark @mark_bottom <anchor 326 644> mark @mark_top;
pos base [Acircumflex] <anchor 316 0> mark @mark_bottom <anchor 326 644> mark @mark_top;
pos base [Atilde] <anchor 316 0> mark @mark_bottom <anchor 326 644> mark @mark_top;

} marklatn;
lookupflag 0;
script cyrl;
lookup markcyrl;
script latn;
lookup marklatn;
lookupflag 0;
} mark;

When I remove ‘script latn;’ or shift ‘script latn; lookup marklatn;’ before
‘script cyrl; lookup markcyrl;’, exporting works.

What’s causing the error?
And defining glyphs in one script as components of another script is a suggested practice in Glyphs, is that right?

Many thanks,

Tom

You could remove the mark feature and let Glyphs build a new one from the anchors.

I let Glyphs build it; there isn’t a pre-existing mark feature.
Please try exporting a font with this glyphs file. ‘languagesystem’ declarations are required to generate the error.

test.zip (3.8 KB)