CustomAttribute with Array Properties sets nulls incorrectly

[JamesAshworth]

An attribute with two array properties does not behave as expected if the first array property is set to a value and the second array property is set to null. If the two arrays are of the same type, the second property is set to the same value as the first property. If the two types are incompatible, an exception is thrown when the attribute is constructed, stating that the second property cannot be found.

Attached are two variations on a simple program that replicates each issue.

Same Type
Incompatible Types

[0xd4d]

The signature of _GetPropertyOrFieldData should be updated from out object value to ref object value since it doesn't always initialize it. Or the native method should be updated to always initialize it.

https://github.com/dotnet/coreclr/blob/master/src/System.Private.CoreLib/src/System/Reflection/CustomAttribute.cs#L1493

value isn't initialized if arraySize == -1.

https://github.com/dotnet/coreclr/blob/master/src/vm/customattribute.cpp#L1004-L1015

[danmoseley]

Thanks for the report and diagnosis. Are either of you interested in offering a PR?

[0xd4d]

@danmosemsft No, but maybe someone else wants to do it.

[danmoseley]

@JamesAshworth ? 😃

[JamesAshworth]

@danmosemsft Not an area I'm confident enough with I'm afraid - not looked at this code before, and haven't got the time at the moment to get familiar.

[danmoseley]

Thanks @JamesAshworth not a problem.

[steveharter]

Moving to future based on priority + schedule.