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Posted to dev@avro.apache.org by "Richard Ahrens (JIRA)" <ji...@apache.org> on 2010/10/27 21:29:20 UTC

[jira] Updated: (AVRO-685) Certain recursive schemas can prevent Schema.RecordSchema.hashCode() and .equals() from returning

     [ https://issues.apache.org/jira/browse/AVRO-685?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Richard Ahrens updated AVRO-685:
--------------------------------

    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	


  was:
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.

I'm unable to include attachments to this Jira issue, but here's 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.

Index: src/java/org/apache/avro/Schema.java
===================================================================
--- src/java/org/apache/avro/Schema.java	(revision 1028064)
+++ src/java/org/apache/avro/Schema.java	(working copy)
@@ -587,21 +587,27 @@
       Set seen = SEEN_EQUALS.get();
       SeenPair here = new SeenPair(this, o);
       if (seen.contains(here)) return true;       // prevent stack overflow
+      boolean first = seen.isEmpty();
       try {
         seen.add(here);
         return fields.equals(((RecordSchema)o).fields);
       } finally {
-        seen.remove(here);
+          if(first) {
+              seen.clear();
+          }
       }
     }
     public int hashCode() {
       Map seen = SEEN_HASHCODE.get();
       if (seen.containsKey(this)) return 0;       // prevent stack overflow
+      boolean first = seen.isEmpty();
       try {
         seen.put(this, this);
         return super.hashCode() + fields.hashCode();
       } finally {
-        seen.remove(this);
+          if(first) {
+              seen.clear();
+          }
       }
     }
     void toJson(Names names, JsonGenerator gen) throws IOException {



I can also provide a sample avpr file to reproduce the issue-- please contact me directly.

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	



> Certain recursive schemas can prevent Schema.RecordSchema.hashCode() and .equals() from returning
> -------------------------------------------------------------------------------------------------
>
>                 Key: AVRO-685
>                 URL: https://issues.apache.org/jira/browse/AVRO-685
>             Project: Avro
>          Issue Type: Bug
>          Components: java
>    Affects Versions: 1.4.1
>         Environment: all
>            Reporter: Richard Ahrens
>            Priority: Critical
>
> 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	

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