Critical Description
I am creating a protocol in memory by building up Schema objects, then writing the avpr file to disk and running SpecificCompiler against it to generate Java sources. My protocol file causes SpecificCompiler to hang. Running in the debugger, I can see a long stack trace emanating from SpecificCompiler.enqueue() (see debugger stack trace at end of this text). What appears to be happening is that Schema.RecordSchema.hashCode() is removing itself from the SEEN_HASHCODE map prematurely; schemas with circular references in multiple fields are added and removed from SEEN_HASHCODE causing the code to bounce around between fields without ever unwinding to the root object.
Attached is a patch that fixes the problem. If this patch is accepted, I'd like to request an incremental release as this is a showstopper for us. I've also attached a sample avpr file that reproduces the issue.
Debugger stack trace referenced above:
org.apache.avro.specific.SpecificCompiler at localhost:3273
Thread [main] (Suspended)
System.identityHashCode(Object) line: not available [native method]
IdentityHashMap<K,V>.hash(Object, int) line: 284
IdentityHashMap<K,V>.put(K, V) line: 412
Schema$RecordSchema.hashCode() line: 601
Schema$LockableArrayList<E>(AbstractList<E>).hashCode() line: 527
Schema$UnionSchema.hashCode() line: 781
Schema$ArraySchema.hashCode() line: 703
Schema$LockableArrayList<E>(AbstractList<E>).hashCode() line: 527
Schema$UnionSchema.hashCode() line: 781
Schema$Field.hashCode() line: 421
Schema$LockableArrayList<E>(AbstractList<E>).hashCode() line: 527
Schema$RecordSchema.hashCode() line: 602
Schema$Field.hashCode() line: 421
Schema$LockableArrayList<E>(AbstractList<E>).hashCode() line: 527
Schema$RecordSchema.hashCode() line: 602
Schema$LockableArrayList<E>(AbstractList<E>).hashCode() line: 527
Schema$UnionSchema.hashCode() line: 781
Schema$Field.hashCode() line: 421
Schema$LockableArrayList<E>(AbstractList<E>).hashCode() line: 527
Schema$RecordSchema.hashCode() line: 602
Schema$LockableArrayList<E>(AbstractList<E>).hashCode() line: 527
Schema$UnionSchema.hashCode() line: 781
Schema$Field.hashCode() line: 421
Schema$LockableArrayList<E>(AbstractList<E>).hashCode() line: 527
Schema$RecordSchema.hashCode() line: 602
Schema$LockableArrayList<E>(AbstractList<E>).hashCode() line: 527
Schema$UnionSchema.hashCode() line: 781
Schema$Field.hashCode() line: 421
Schema$LockableArrayList<E>(AbstractList<E>).hashCode() line: 527
Schema$RecordSchema.hashCode() line: 602
Schema$LockableArrayList<E>(AbstractList<E>).hashCode() line: 527
Schema$UnionSchema.hashCode() line: 781
Schema$Field.hashCode() line: 421
Schema$LockableArrayList<E>(AbstractList<E>).hashCode() line: 527
Schema$RecordSchema.hashCode() line: 602
Schema$LockableArrayList<E>(AbstractList<E>).hashCode() line: 527
Schema$UnionSchema.hashCode() line: 781
Schema$Field.hashCode() line: 421
Schema$LockableArrayList<E>(AbstractList<E>).hashCode() line: 527
Schema$RecordSchema.hashCode() line: 602
Schema$LockableArrayList<E>(AbstractList<E>).hashCode() line: 527
Schema$UnionSchema.hashCode() line: 781
Schema$Field.hashCode() line: 421
Schema$LockableArrayList<E>(AbstractList<E>).hashCode() line: 527
Schema$RecordSchema.hashCode() line: 602
Schema$LockableArrayList<E>(AbstractList<E>).hashCode() line: 527
Schema$UnionSchema.hashCode() line: 781
Schema$ArraySchema.hashCode() line: 703
Schema$Field.hashCode() line: 421
Schema$LockableArrayList<E>(AbstractList<E>).hashCode() line: 527
Schema$RecordSchema.hashCode() line: 602
HashMap<K,V>.getEntry(Object) line: 344
HashMap<K,V>.containsKey(Object) line: 335
HashSet<E>.contains(Object) line: 184
SpecificCompiler.enqueue(Schema) line: 134
SpecificCompiler.<init>(Protocol) line: 70
SpecificCompiler.compileProtocol(File, File) line: 114
SpecificCompiler.main(String[]) line: 399