Error passing bindings to cxx for autocxx subclass using POD with certain fields

[tychedelia]

These two fields cause cxx to reject the bindings generated for our subclass method:

  --- stderr
  Error:
    × cxx couldn't handle our generated bindings - could be a bug in autocxx:
    │ unsupported type: MyPod

It also appears to be an issue using rust::Slice<float> or rust::Vec<float> (float* works fine as expected).

I am a C++ noob but I can't understand what's problematic about these fields.

Expected Behavior

cxx accepts the bindings, or autocxx generates an error when generating the subclass describing why the POD type isn't valid.

Actual Behavior

cxx rejects the bindings without any additional error info.

Steps to Reproduce the Problem

See linked fork above, uncomment "bad fields" in MyPod and run cargo run.

[adetaylor]

Thanks. I agree the error messages here aren't good enough. I'll work on them next time I get a chance.

[tychedelia]

For anyone who might want to look at this for a first issue, it does appear that the error is being correctly generated here. If you look at the Rust code generated here and passed to cxx, you can see that the real error is correctly noted in the doc strings. In my case, that leads me to these issues #266 #199

[tychedelia]

@adetaylor Looks like if I just allow pointer-to-pointer here by removing the error, everything works okay, at least for the subclass example in my diff. There's a failing integration test test_pointer_to_pointer, but that looks to be guarding against a different kind of indirection than my simple nested array POD use case. Is there a way that we could allow this and generate a better error in the "troublesome API" case shown in the test? This would be hugely helpful in unblocking me!

[adetaylor]

Thanks for taking a look at this and sorry for missing your messages two years ago. Feel free to raise a PR and I'll take a look.