Re: Probable bug within sun.management.StackTraceElementCompositeData

[David Holmes]

Hi Sven,

Moving to serviceability-dev mailing list. Please don't reply to jdk-dev.

Thanks,
David

On 15/10/2018 5:42 AM, Sven Reimers wrote:

Hi all,

I hope this is the correct e-mailing list. During out testing of Apache
NetBeans 10 we discovered a problem with self sampling capability of
NetBeans. Digging further into this problem (NETBEANS-1359
<https://issues.apache.org/jira/browse/NETBEANS-1359>) I debugged through
the code and it seems that there is a problem with the order of the values
and the order of the attributes.

 From the code I see the order of the values is

         final Object[] stackTraceElementItemValues = {
             ste.getClassLoaderName(),
             ste.getModuleName(),
             ste.getModuleVersion(),
             ste.getClassName(),
             ste.getMethodName(),
             ste.getFileName(),
             ste.getLineNumber(),
             ste.isNativeMethod(),
         };

compared to  the order of the attributes


     private static final String[] V5_ATTRIBUTES = {
         CLASS_NAME,
         METHOD_NAME,
         FILE_NAME,
         LINE_NUMBER,
         NATIVE_METHOD,
     };

     private static final String[] V9_ATTRIBUTES = {
         CLASS_LOADER_NAME,
         MODULE_NAME,
         MODULE_VERSION,
     };

     private static final String[] STACK_TRACE_ELEMENT_ATTRIBUTES =
         Stream.of(V5_ATTRIBUTES, V9_ATTRIBUTES).flatMap(Arrays::stream)
               .toArray(String[]::new);

which can be expanded to

         CLASS_NAME,
         METHOD_NAME,
         FILE_NAME,
         LINE_NUMBER,
         NATIVE_METHOD,
         CLASS_LOADER_NAME,
         MODULE_NAME,
         MODULE_VERSION,

With the difference in ordering you will get an exception  in
CompositeDataSupport, if you try to convert things (lines 228ff)

         // Check each value, if not null, is of the open type defined for
the
         // corresponding item
         for (String name : namesFromType) {
             Object value = items.get(name);
             if (value != null) {
                 OpenType<?> itemType = compositeType.getType(name);
                 if (!itemType.isValue(value)) {
                     throw new OpenDataException(
                             "Argument value of wrong type for item " + name
+
                             ": value " + value + ", type " + itemType);
                 }
             }
         }

which is hard to compensate from the caller side.

I think the change, which introduced this was

https://github.com/openjdk/jdk/commit/9091926ae64690982d59f1d634f96bb9b79a5470

The proposed patch seems simple, just change the ordering of the attributes

   private static final String[] STACK_TRACE_ELEMENT_ATTRIBUTES =
         Stream.of(V9_ATTRIBUTES, V5_ATTRIBUTES).flatMap(Arrays::stream)
               .toArray(String[]::new);

or change the value ordering to fit the attributes order.

Can anyone confirm the analysis?

Thanks

-Sven