structs of structs don't seem to work

[etheory]

Describe the bug

Adding a struct to a struct seems to result in undefined initialization behavior.

OSL version and dependencies

• OSL branch/version: 1.13.12.0.2
• OS: Rocky Linux release 9.4
• C++ compiler: clang-15.0.7.3
• LLVM version: llvm-15.0.7.1
• OIIO version: OpenImageIO-2.4.13.0.4
• Qt version: Qt-5.15.3.8

To Reproduce

Steps to reproduce the behavior:

Given the following structs:

struct StructA
{
  float cellRand;
  point minDist;
  point closest;
  point secondClosest;
  float edgeDist;
};

struct StructB
{
  StructA result;
  int level;
  float scale;
};

and given a shading function with signature:

StructA somefunction();

If you try and initialize using:

StructB value = StructB(somefunction(), 0, 1.0);

all the attributes are correctly set in the various structs, but if, instead, you do:

StructA temp = somefunction();
StructB value = StructB(temp, 0, 1.0);

then value is incorrect, and the result member is filled with zeroes.

Evidence

• I was trying to assemble a full test example using osltoy, but was blocked by: https://github.com/AcademySoftwareFoundation/OpenShadingLanguage/issues/2035

It'd be great for someone else to confirm they can reproduce this behavior, thanks!

[etheory]

@ld-kerley has suggested to use list initalization as a workaround in the short term. I'll give that a go.

[etheory]

@ld-kerley I tried your suggestion but it didn't work. List initializing still results in empty structures for me.