Fix the order of feature writers

We want curs feature lookups to come first, then kerning, then mark/mkmk, but we currently are calling CursFeatureWriter last which causes its lookups to be also written last. The lookup order does not matter for HarfBuzz, but it matters for other implementations, see: harfbuzz/harfbuzz#4596 (comment)
googlefonts · Aug 28, 2024 · 9dd2f92 · 9dd2f92
1 parent bb79cae
commit 9dd2f92
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Showing 2 changed files with 11 additions and 11 deletions.
diff --git a/Lib/ufo2ft/featureCompiler.py b/Lib/ufo2ft/featureCompiler.py
@@ -172,10 +172,10 @@ class FeatureCompiler(BaseFeatureCompiler):
     """
 
     defaultFeatureWriters = [
+        CursFeatureWriter,
         KernFeatureWriter,
         MarkFeatureWriter,
         GdefFeatureWriter,
-        CursFeatureWriter,
     ]
 
     def __init__(

diff --git a/tests/featureWriters/variableFeatureWriter_test.py b/tests/featureWriters/variableFeatureWriter_test.py
@@ -19,6 +19,16 @@ def test_variable_features(FontClass):
         markClass dotabove-ar <anchor (wght=100:100 wght=1000:125) (wght=100:320 wght=1000:416)> @MC_top;
         markClass gravecmb <anchor 250 400> @MC_top;
 
+        feature curs {
+            lookup curs_rtl {
+                lookupflag RightToLeft IgnoreMarks;
+                pos cursive alef-ar.fina <anchor (wght=100:299 wght=1000:330) (wght=100:97 wght=1000:115)> <anchor NULL>;
+                pos cursive peh-ar.init <anchor NULL> <anchor (wght=100:161 wght=1000:73) (wght=100:54 wght=1000:89)>;
+                pos cursive peh-ar.init.BRACKET.varAlt01 <anchor NULL> <anchor (wght=100:89 wght=1000:73) (wght=100:53 wght=1000:85)>;
+            } curs_rtl;
+
+        } curs;
+
         lookup kern_Arab {
             lookupflag IgnoreMarks;
             pos alef-ar.fina alef-ar.fina <(wght=100:15 wght=1000:35) 0 (wght=100:15 wght=1000:35) 0>;
@@ -47,16 +57,6 @@ def test_variable_features(FontClass):
         table GDEF {
             LigatureCaretByPos peh-ar.init 100;
         } GDEF;
-
-        feature curs {
-            lookup curs_rtl {
-                lookupflag RightToLeft IgnoreMarks;
-                pos cursive alef-ar.fina <anchor (wght=100:299 wght=1000:330) (wght=100:97 wght=1000:115)> <anchor NULL>;
-                pos cursive peh-ar.init <anchor NULL> <anchor (wght=100:161 wght=1000:73) (wght=100:54 wght=1000:89)>;
-                pos cursive peh-ar.init.BRACKET.varAlt01 <anchor NULL> <anchor (wght=100:89 wght=1000:73) (wght=100:53 wght=1000:85)>;
-            } curs_rtl;
-
-        } curs;
 """  # noqa: B950
     )