Openpmd-api: Incomplete error message

[eschnett]

While debugging the Julia wrapper of openPMD-api, I received the error message below. It is incomplete, and it does not give any information about the second type.

LoadError: [ADIOS2] Trying to access a dataset with wrong type (trying to access dataset with type int64_t, but has type )

I would have expected to see a type name there, of if there is somehow no type information, say why it is missing.

Software Environment

• version of openPMD-api: [0.14.0], this branch
• installed openPMD-api via: [Yggdrasil]
• operating system: [macOS 11.4]
• machine: [laptop]
• name and version of Python implementation: [n/a]
• version of HDF5: [n/a]
• version of ADIOS1: [n/a]
• version of ADIOS2: [2.7.1]
• name and version of MPI: [MPICH 3.4.2]

[franzpoeschel]

ADIOS2 reports datatypes as strings, and when a datatype cannot be found (e.g. when a variable is not found), it returns an empty string, which is what you're seeing here.
The error message seems a bit cryptic as a result, I'll look into making this more understandable.

[franzpoeschel]

Fixed with #1036