Exception when reconstructing a type inside a collection with a specific type parameter #374
Comments
Octogonapus
changed the title
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Hi @Octogonapus , Defining |
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I think this could be handled with a look-ahead inside ┌ Debug: constructrr
│ T = Main.Foo.Outer
│ dt = JLD2.CompoundDatatype(0x00000008, [:a], [0], JLD2.H5Datatype[JLD2.BasicDatatype(0x37, 0x00, 0x00, 0x00, 0x00000008)])
│ attrs =
│ 1-element Vector{JLD2.ReadAttribute}:
│ JLD2.ReadAttribute(:julia_type, JLD2.ReadDataspace(0x00, 0x00, 4891), 0xff, 560, 4891)
└ @ JLD2 ~/Documents/code/JLD2.jl/src/data/reconstructing_datatypes.jl:121
┌ Debug: field_datatypes
│ field_datatypes = JLD2.RelOffset[]
└ @ JLD2 ~/Documents/code/JLD2.jl/src/data/reconstructing_datatypes.jl:123
┌ Debug: isconcretetype(T)
│ isconcretetype(T) = true
└ @ JLD2 ~/Documents/code/JLD2.jl/src/data/reconstructing_datatypes.jl:126
┌ Debug: dtnames & mapped
│ dtnames =
│ Dict{Symbol, Int64} with 1 entry:
│ :a => 1
│ mapped =
│ 1-element BitVector:
│ 0
└ @ JLD2 ~/Documents/code/JLD2.jl/src/data/reconstructing_datatypes.jl:138
┌ Debug: determine dtrr
│ field_datatypes = JLD2.RelOffset[]
│ dtindex = 1
│ dt.members =
│ 1-element Vector{JLD2.H5Datatype}:
│ JLD2.BasicDatatype(0x37, 0x00, 0x00, 0x00, 0x00000008)
└ @ JLD2 ~/Documents/code/JLD2.jl/src/data/reconstructing_datatypes.jl:161
┌ Debug: dtrr
│ dtrr = JLD2.ReadRepresentation{Any, JLD2.RelOffset}()
│ typeof(dtrr) = JLD2.ReadRepresentation{Any, JLD2.RelOffset}
│ (typeof(dtrr)).parameters = svec(Any, JLD2.RelOffset)
└ @ JLD2 ~/Documents/code/JLD2.jl/src/data/reconstructing_datatypes.jl:168
┌ Debug: constructrr type intersection
│ readtype = Any
│ wstype = Vector{Main.Foo.Inner} (alias for Array{Main.Foo.Inner, 1})
│ typeintersect(readtype, wstype) = Vector{Main.Foo.Inner} (alias for Array{Main.Foo.Inner, 1})
│ hasmethod(convert, Tuple{Type{wstype}, readtype}) = false
└ @ JLD2 ~/Documents/code/JLD2.jl/src/data/reconstructing_datatypes.jl:171If I may also work on implementing a "reconstructed types only" feature, as described in #242. |
I've looked at the source code and the files. Sadly I'm pretty sure this is not possible.
I believe it may be more useful to implement the explicit type remapping that's already working in #316. |
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Since I had the code lying around already I ended up doing the above myself in #376 . |
Description
Using Julia v1.6 and JLD2 v0.4.19, JLD2 fails to load a struct containing a vector of a type which must be reconstructed. In principal, this makes sense, as the reconstructed type isn't convertible to the required type on the vector. This behavior isn't very helpful, though, as the exception occurs inside JLD2 code so I don't have an opportunity to address the problem.
My code can provide a way to convert a reconstructed
Foo.Innerinto a trueFoo.Inner. Would it be possible to pass this function to JLD2 somehow? I'm not sure how my conversion method would get the required type information, though. I can see that JLD2 has this information, since it creates type names like thisJLD2.ReconstructedTypes.var"##Main.Foo.Inner#258". That is probably enough to implement the conversion function I have in mind. In our own code, we save the type name as a string next to the data, and then use that to convert any reconstructed types into the true types. We need to do this conversion in the first place because we need to dispatch on these types; dispatch won't work with reconstructed types.I'd also like I note that I can help work on this change, if it's something that would be accepted.
Workaround
I could change the type of
Outer.atoVector, but this not ideal as I want to require a specific eltype on that vector.I could also define a method of
convertlike thisBase.convert(::Type{Inner}, other) = Inner(other.x, 0), but I can't think of a way to provide a tight enough type bound onotherso that this function won't get accidentally called.MWE
Step 1: Serialize
Step 2: Deserialize with an Added Field
Exception
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