the patch is stale, since I took so long to review it. Sorry!
No worries. I've updated the patch.
It's always strangely pleasant when patches go stale because there are new features to adapt to.
why all the SpecificCompiler#doc() methods? Why not just call, e.g., doc(out, indent, schema.getDoc())?
It was a good idea when there were only 2 types, and it felt cleaner. Fixed it to just use String and one doc() method. Avoided the temptation to introduce a "hasDoc" interface.
shouldn't we now also extend avrogen to copy comments through?
AVRO-296. It needs to be done, but it's not 100% trivial (because javacc strips out comments, and that needs to get undone), so I'd rather take a pass at it separately.