Field XXX has non-zero size in file, this should not happen

[dpinol]

On version 0.5.1, when using typemap for upgrades, we get the following message for some kinds of types (for Symbols & enums, but not for Ints and Strings)
Field XXX has non-zero size in file, this should not happen

You can reproduce with this:

using JLD2

@enum MyEnum begin
    A = 1
end

Base.@kwdef struct KK
    enum::MyEnum = A
    int::Int = 0
    field::Symbol = :KK2
    str::String = "jkjk"
end

function JLD2.rconvert(::Type{KK}, deserialized::NamedTuple)
    return KK(; deserialized...)
end

save("kk.jld2", Dict("kk" => KK()))
load("kk.jld2"; typemap=Dict("KK" => JLD2.Upgrade(KK)))

┌ Warning: Field enum has non-zero size in file, this should not happen
└ @ JLD2 ~/.julia/packages/JLD2/JHhTf/src/data/reconstructing_datatypes.jl:595
┌ Warning: Field field has non-zero size in file, this should not happen
└ @ JLD2 ~/.julia/packages/JLD2/JHhTf/src/data/reconstructing_datatypes.jl:595

[JonasIsensee]

Hm, I actually can't reproduce..

julia> using JLD2
Precompiling JLD2
  1 dependency successfully precompiled in 26 seconds. 7 already precompiled.

julia> @enum MyEnum begin
           A = 1
       end

julia> Base.@kwdef struct KK
           enum::MyEnum = A
           int::Int = 0
           field::Symbol = :KK2
           str::String = "jkjk"
       end
KK

julia> function JLD2.rconvert(::Type{KK}, deserialized::NamedTuple)
           return KK(; deserialized...)
       end

julia> save("kk.jld2", Dict("kk" => KK()))

julia> load("kk.jld2"; typemap=Dict("KK" => JLD2.Upgrade(KK)))
Dict{String, Any} with 1 entry:
  "kk" => KK(A, 0, :KK2, "jkjk")

I am not sure what is going on at your side.
You clearly managed to trigger the problem.
Will be happy to help with some more info.

What Julia version are you on?

[dpinol]

Hi,
thanks for looking into this.
After some digging I found out it only happens when executing in a test with Jive.jl (or through Juliacall python library).
Looking at jive.jl code I found out that you can reproduce it with:

• Write my code above in a file named kk.jl
• Execute this from REPL Base.include(Module(), "kk.jl"). This is done to ensure that each test file is executed on a different Module to avoid that 'using's in one test file affect the other test files.

[dpinol]

Btw, I also get these different messages in 0.5.1 when doing Base.include

┌ Warning: type Main.anonymous.KK does not exist in workspace; reconstructing
└ @ JLD2 ~/.julia/packages/JLD2/JHhTf/src/data/reconstructing_datatypes.jl:573
┌ Warning: type Main.anonymous.MyEnum does not exist in workspace; reconstructing
└ @ JLD2 ~/.julia/packages/JLD2/JHhTf/src/data/reconstructing_datatypes.jl:457

[JonasIsensee]

Ok, I found the problem.
Well, the problem is really just an overly eager warning message that I will need to remove.

This bit is expected and also exists on older versions:
You're storing types defined in an anonymous module. Therefore they are stored with name Main.anonymous.KK and cannot be recovered since Main.anonymous is not actually a valid name.

Btw, I also get these different messages in 0.5.1 when doing Base.include

┌ Warning: type Main.anonymous.KK does not exist in workspace; reconstructing
└ @ JLD2 ~/.julia/packages/JLD2/JHhTf/src/data/reconstructing_datatypes.jl:573
┌ Warning: type Main.anonymous.MyEnum does not exist in workspace; reconstructing
└ @ JLD2 ~/.julia/packages/JLD2/JHhTf/src/data/reconstructing_datatypes.jl:457

[dpinol]

Cool, thanks!
My tests all pass so I agree that the problem doesn't affect the library behaviour.