[layout] Change order of feature collection
See comments for rationale.
Fixes https://github.com/harfbuzz/harfbuzz/issues/4445
diff --git a/src/hb-ot-layout.cc b/src/hb-ot-layout.cc
index 5ce3669..2eb8535 100644
--- a/src/hb-ot-layout.cc
+++ b/src/hb-ot-layout.cc
@@ -1308,11 +1308,16 @@
unsigned int count = l.get_feature_indexes (0, nullptr, nullptr);
feature_map->alloc (count);
- for (unsigned int i = 0; i < count; i++)
+ /* Loop in reverse, such that earlier entries win. That emulates
+ * a linear search, which seems to be what other implementations do.
+ * We found that with arialuni_t.ttf, the "ur" language system has
+ * duplicate features, and the earlier ones work but not later ones.
+ */
+ for (unsigned int i = count; i; i--)
{
unsigned feature_index = 0;
unsigned feature_count = 1;
- l.get_feature_indexes (i, &feature_count, &feature_index);
+ l.get_feature_indexes (i - 1, &feature_count, &feature_index);
if (!feature_count)
break;
hb_tag_t feature_tag = g.get_feature_tag (feature_index);
