Hi,

I noticed a strange behaviour with scijava parameters. It looks like the handling of array parameters are very different if they contain a generics wildcard or not:

Let's imagine a class:

public class MyClass<T> {

}

And a scijava converter from String to MyClass<?>[] (not sure the wildcard changes anything if present in the converter)

This:

@Parameter
MyClass[] myobjects;

behaves correctly with regards to the scijava mechanism. The correct converter is called.

However this:

@Parameter
MyClass<?>[] myobjects;

completely fails : in the test case I have, the scijava mechanism attempts to put a File[] object into myobjects, obviously failing.

I narrowed down the issue to the CommandModuleItem class. The line

I have not made a minimal example of this issue, but one test in bigdataviewer-playground can be used to reproduce the issue : https://github.com/bigdataviewer/bigdataviewer-playground/blob/fixes-rawtype/src/test/src/sc/fiji/bdvpg/scijava/ScijavaShowDemo.java.

The demo fails. But if you remove the wildcard in the line https://github.com/bigdataviewer/bigdataviewer-playground/blob/daab0a336831b89c44d13932c243dd41e493dbe5/src/main/java/sc/fiji/bdvpg/scijava/command/bdv/BdvSourcesAdderCommand.java#L49:

SourceAndConverter[] sacs;

Then everything works.

How can this be solved ? I'm also open to suggestions on my code. I tend to fear that modifying scijava common is risky. So if there's a solution on bigdataviewer-playground side I would rather do it. I can think of 3 options:

• keeping raws type in the parameters : this creates annoying issues when converting to List + we are not supposed to use raw types in Java as far as I understood
• making a container class : SourceAndConverterList which would hold a single field List<SourceAndConverter>. This seems the most easy thing to do a provides a lot of control on the scijava side - but it's a bit inelegant
• managing to make a working List<SourceAndConverter<?>> scijava parameter, but I have no idea if this is possible. To me, because the generic types are erased at runtime, this looks impossible, but is it really ?

Here's some maybe related issues:

#172

#118