Bug with omar-type fonts Arabic shaping, joining is inconsistent with YEH, BEH and JIM. about hamza HOT 1 CLOSED

I might have found the source of this bug, in the GSUB multiple substitution code. This latter switch case will free nested (unlike ligature substitution, which recycles the starting node) which comes from an instance of hz_sequence_node_cache_t from the GSUB chained contextual substitution code. This bug really is a result of a bad understanding of how that lookup is meant to function anyway, if there are multiple nested lookups to apply on the same context, then the indices of subsequent operations take into account to modified sequence context. This means that in nested lookups, the code has to be quite different as to either update the node cache, or I would have to iterate over the original sequence again and again, after each nested lookup. This to me ... seems slower. Here's the documentation for reference on how this is supposed to work.

from hamza.