Isn't all this other code just as broken if it uses prepare_cached with DBD::Sybase? And if it doesn’t use prepare_cached with DBD::Sybase, why would it be affected? And if you patch Class::DBI instead, wouldn’t that affect all CDBI apps, even those that shouldn’t be, like someone whipping up some quick using DBD::SQLite off at a corner of the environment? Patching DBD::Sybase seems to scope the fix to the right layer, whereas patching CDBI would be a scattershot that would affect code which shouldn’t be and miss code that should be.
(Note: I’m not arrogating any say in your decision, just pointing out what seems like a mistake to me. The call is obviously yours since you’re the one who’ll have to live with the consequences.)
Makeshifts last the longest.