MPI_TESTANY is described in MPI-1 p46. The last 2 full paragraphs of

the page address three situations:

1. if the array of requests are all REQUEST_NULL, set flag=true and
   index=MPI_UNDEFINED
2. if the array of requests are not all REQUEST_NULL, if any of them
   finished, set flag=true and index=whatever_the_index_was
3. if the array of requests are not all REQUEST_NULL, if none of them
   finished, set flag=false and index=MPI_UNDEFINED

With regards to the index value, we are currently doing 1 and 2, but
not 3.  More specifically, index should be set to MPI_UNDEFINED if no
requests are found to have completed (regardless of whether they are
REQUEST_NULL or not).

This patch fixes this problem.

This commit was SVN r8319.

ompi/request/req_test.c

@@ -53,13 +53,13 @@ int ompi_request_test_any(
     }
 
     /* Only fall through here if we found nothing */
+    *index = MPI_UNDEFINED;
     if(num_requests_null_inactive != count) {
         *completed = false;
 #if OMPI_ENABLE_PROGRESS_THREADS == 0
         opal_progress();
 #endif
     } else {
-        *index = MPI_UNDEFINED;
         *completed = true;
         if (MPI_STATUS_IGNORE != status) {
             *status = ompi_status_empty;