Issue with `Union{Missing, VersionNumber}`

[ericphanson]

Issue with `Union{Missing, VersionNumber}`

[quinnj]

Ok, fix is up: #465. I believe this has always been an issue. Kind of a gnarly one, but I think the solution proposed should be robust for structs.

[Moelf]

https://github.com/JuliaLang/julia/blob/c58e508fddba24a7508b3018aa7f413362b384ca/base/version.jl#L43-L44

technically this is indeed not fixed number of fields

[ericphanson]

I'm not sure if that's the issue, as VersionNumber's alone work:

julia> struct C
       v::VersionNumber
       end

julia> table = [C(v"1")]
1-element Vector{C}:
 C(v"1.0.0")

julia> Arrow.tobuffer(table)
IOBuffer(data=UInt8[...], readable=true, writable=true, seekable=true, append=false, size=1144, maxsize=Inf, ptr=1, mark=-1)

and e.g. fieldcount(VersionNumber) works fine.

[quinnj]

Do we know if this used to work and regressed? Or perhaps just never worked?

[ericphanson]

I’m not sure, I’ve definitely serialized VersionNumbers before, but maybe not with missing. This came up in a new application, it didn’t break a working one.

[quinnj]

Alternative fix is up: #466