Deactivate Span API by default in BP5

[franzpoeschel]

Workaround for this bug ornladios/ADIOS2#4586.
Since BP5 can write directly from user buffers, this change (essentially activating our fallback implementation) is not too costly.

TODO:

• Wait for an answer in the issue linked above. The current draft assumes that this will be fixed in upcoming versions, but let's be sure of that.

[guj]

This bug was fixed in BP5. Should span be allowed again in BP5?

[franzpoeschel]

This bug was fixed in BP5. Should span be allowed again in BP5?

It is allowed based on the discovered ADIOS2 version, any version newer than 2.10.2 will use the Span API by default again:

#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

Do you know if the error you saw is related to this?

[guj]

The one from master is 2.10.0.735 from bpls -V
so that's why span was deactivated.