Deactivate Span API by default in BP5 (#1771)

* Deactivate Span API by default in BP5

* Link the fix PR

Author: franzpoeschel

src/IO/ADIOS/ADIOS2IOHandler.cpp

@@ -1247,6 +1247,12 @@ void ADIOS2IOHandlerImpl::getBufferView(
     Writable *writable, Parameter<Operation::GET_BUFFER_VIEW> &parameters)
 {
     // @todo check access mode
+    /*
+     * We will check BP5 again below. BP5 fundamentally supports the Span API,
+     * but runs into this bug https://github.com/ornladios/ADIOS2/issues/4586,
+     * fixed by https://github.com/ornladios/ADIOS2/pull/4587,
+     * so we treat the Span API as opt-in there.
+     */
     std::string optInEngines[] = {"bp4", "bp5", "file", "filestream"};
     if (std::none_of(
             begin(optInEngines),
@@ -1270,7 +1276,17 @@ void ADIOS2IOHandlerImpl::getBufferView(
         return;
     case UseSpan::Auto:
         if (switchAdios2VariableType<detail::HasOperators>(
-                parameters.dtype, name, ba.m_IO))
+                parameters.dtype, name, ba.m_IO)
+#if (                                                                          \
+    ADIOS2_VERSION_MAJOR * 1000 + ADIOS2_VERSION_MINOR * 10 +                  \
+    ADIOS2_VERSION_PATCH) <= 2102
+            ||
+            // Deactivate the Span API in BP5 by default due to this bug
+            // https://github.com/ornladios/ADIOS2/issues/4586,
+            // fixed by https://github.com/ornladios/ADIOS2/pull/4587
+            this->realEngineType() == "bp5"
+#endif
+        )
         {
             parameters.out->backendManagedBuffer = false;
             return;

test/Files_ParallelIO/iterate_nonstreaming_series.cpp

@@ -21,7 +21,18 @@ static auto run_test(
     size_t const extent = base_extent * size_t(mpi_size);
 
     {
-        Series writeSeries(file, Access::CREATE, MPI_COMM_WORLD, jsonConfig);
+        Series writeSeries(
+            file,
+            Access::CREATE,
+            MPI_COMM_WORLD,
+            /*
+             * The ADIOS2 backend deactivates the Span API by default due to
+             * this bug: https://github.com/ornladios/ADIOS2/issues/4586,
+             * fixed by https://github.com/ornladios/ADIOS2/pull/4587.
+             * For this test, we enable it.
+             */
+            json::merge(
+                jsonConfig, R"({"adios2":{"use_span_based_put": true}})"));
         if (variableBasedLayout)
         {
             writeSeries.setIterationEncoding(IterationEncoding::variableBased);

test/SerialIOTest.cpp

@@ -6394,7 +6394,17 @@ void iterate_nonstreaming_series(
 {
     constexpr size_t extent = 100;
     {
-        Series writeSeries(file, Access::CREATE, jsonConfig);
+        Series writeSeries(
+            file,
+            Access::CREATE,
+            /*
+             * The ADIOS2 backend deactivates the Span API by default due to
+             * this bug: https://github.com/ornladios/ADIOS2/issues/4586,
+             * fixed by https://github.com/ornladios/ADIOS2/pull/4587.
+             * For this test, we enable it.
+             */
+            json::merge(
+                jsonConfig, R"({"adios2":{"use_span_based_put": true}})"));
         if (variableBasedLayout)
         {
             writeSeries.setIterationEncoding(IterationEncoding::variableBased);