# Rescuing old Julia 0.5 Nullable{Date} type in 0.6

**URL:** https://discourse.julialang.org/t/rescuing-old-julia-0-5-nullable-date-type-in-0-6/11818
**Category:** General Usage
**Created:** [June 20, 2018, 11:11am UTC](https://discourse.julialang.org/t/rescuing-old-julia-0-5-nullable-date-type-in-0-6/11818 "2018-06-20T11:11:52Z")
**Posts on this page:** 8
**Page:** 1

<div class="post-metadata">

### Author: ![acunningham](https://avatars.discourse-cdn.com/v4/letter/a/96bed5/32.png) [@acunningham](https://discourse.julialang.org/u/acunningham)
#### Post date: [June 20, 2018, 11:11am UTC](https://discourse.julialang.org/t/rescuing-old-julia-0-5-nullable-date-type-in-0-6/11818/1 "2018-06-20T11:11:52Z")

</div>

Hi,

I’m upgrading to from Julia 0.5 to Julia 0.6 but I’m having some problems reading old JLD files with Nullable{Date} field.

Julia 0.5 type below:

```julia
type foo5
    id::Int64
    rollup_date::Nullable{Date}
end

```

Julia 0.6 type:

```julia
mutable struct foo5
    id::Int64
    rollup_date::Nullable{Date}
    
end

```

Following the JLD docs for rescuing old types I have the following:

```julia
type OldNullable{T}
    isnull::Bool
    value::T
end

JLD.readas(x::OldNullable) = Nullable(x.value, !x.isnull)
JLD.translate("Base.Nullable{Base.Dates.Date}", "OldNullable{Base.Dates.Date}")

path = "c:\\foo5.jld"
file_dir, file_name = splitdir(path)
file_prefix, file_ext = splitext(file_name)
obj = JLD.load(path, file_prefix)

```

After trying to load this type I get the following error:

```julia
stored type foo5 does not match currently loaded type

Stacktrace:
 [1] jldatatype(::JLD.JldFile, ::HDF5.HDF5Datatype) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\jld_types.jl:721
 [2] read(::JLD.JldDataset) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\JLD.jl:368
 [3] read(::JLD.JldFile, ::String) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\JLD.jl:344
 [4] (::JLD.##41#42{String})(::JLD.JldFile) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\JLD.jl:1241
 [5] #jldopen#11(::Array{Any,1}, ::Function, ::JLD.##41#42{String}, ::String, ::Vararg{String,N} where N) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\JLD.jl:243
 [6] load(::FileIO.File{FileIO.DataFormat{:JLD}}, ::String) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\JLD.jl:1240
 [7] #load#13(::Array{Any,1}, ::Function, ::String, ::String, ::Vararg{String,N} where N) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\FileIO\src\loadsave.jl:113
 [8] load(::String, ::String) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\FileIO\src\loadsave.jl:113

```

Any ideas or anything obvious that I’m doing wrong?

Regards,  
Adrian.

---

<div class="post-metadata">

### Author: ![rdeits](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/rdeits/32/286_2.png) [@rdeits](https://discourse.julialang.org/u/rdeits)
#### Post date: [June 20, 2018, 2:59pm UTC](https://discourse.julialang.org/t/rescuing-old-julia-0-5-nullable-date-type-in-0-6/11818/2 "2018-06-20T14:59:40Z")

</div>

Nullables are immutable, so perhaps your OldNullable should be a `struct` (the new equivalent of the old `immutable`) instead. I realize that your code matches the readme, but it’s possible that the readme is incorrect. See [https://github.com/JuliaIO/JLD.jl/issues/180](https://github.com/JuliaIO/JLD.jl/issues/180) where the version that worked used a `struct` for OldNullable.

---

<div class="post-metadata">

### Author: ![acunningham](https://avatars.discourse-cdn.com/v4/letter/a/96bed5/32.png) [@acunningham](https://discourse.julialang.org/u/acunningham)
#### Post date: [June 21, 2018, 10:33am UTC](https://discourse.julialang.org/t/rescuing-old-julia-0-5-nullable-date-type-in-0-6/11818/3 "2018-06-21T10:33:58Z")

</div>

hmm…tried that, still doesn’t seem to work.

If I do exactly as the link states, I can write a 0.5 Nullable{Date} to disk and read in 0.6. But it doesn’t work when I have it nested inside my type.

---

<div class="post-metadata">

### Author: ![pearlzli](https://avatars.discourse-cdn.com/v4/letter/p/76d3ee/32.png) [@pearlzli](https://discourse.julialang.org/u/pearlzli)
#### Post date: [June 25, 2018, 6:19pm UTC](https://discourse.julialang.org/t/rescuing-old-julia-0-5-nullable-date-type-in-0-6/11818/4 "2018-06-25T18:19:39Z")

</div>

Could you try also defining an `OldFoo5` type and corresponding `readas` method and `translate` call?

---

<div class="post-metadata">

### Author: ![acunningham](https://avatars.discourse-cdn.com/v4/letter/a/96bed5/32.png) [@acunningham](https://discourse.julialang.org/u/acunningham)
#### Post date: [June 25, 2018, 7:45pm UTC](https://discourse.julialang.org/t/rescuing-old-julia-0-5-nullable-date-type-in-0-6/11818/5 "2018-06-25T19:45:05Z")

</div>

Yep, tried that, still does not work:

```julia
import JLD

struct OldNullable{T}
    isnull::Bool
    value::T
end

JLD.readas(x::OldNullable) = Nullable(x.value, !x.isnull)
JLD.translate("Base.Nullable{Base.Dates.Date}", "OldNullable{Base.Dates.Date}")

mutable struct foo5 
    id::Int64
    rollup_date::Nullable{Date}
end

mutable struct oldfoo5
    id::Int64
    rollup_date::Nullable{Date}
end

JLD.readas(x::oldfoo5) = foo5(x.id, x.rollup_date)
JLD.translate("foo5", "oldfoo5")

path = "c:\\foo5.jld"
file_dir, file_name = splitdir(path)
file_prefix, file_ext = splitext(file_name)
obj = JLD.load(path, file_prefix)

```

gives the same error:

```julia
stored type oldfoo5 does not match currently loaded type

Stacktrace:
 [1] jldatatype(::JLD.JldFile, ::HDF5.HDF5Datatype) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\jld_types.jl:721
 [2] read(::JLD.JldDataset) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\JLD.jl:368
 [3] read(::JLD.JldFile, ::String) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\JLD.jl:344
 [4] (::JLD.##41#42{String})(::JLD.JldFile) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\JLD.jl:1241
 [5] #jldopen#11(::Array{Any,1}, ::Function, ::JLD.##41#42{String}, ::String, ::Vararg{String,N} where N) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\JLD.jl:243
 [6] load(::FileIO.File{FileIO.DataFormat{:JLD}}, ::String) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\JLD.jl:1240
 [7] #load#13(::Array{Any,1}, ::Function, ::String, ::String, ::Vararg{String,N} where N) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\FileIO\src\loadsave.jl:113
 [8] load(::String, ::String) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\FileIO\src\loadsave.jl:113

```

---

<div class="post-metadata">

### Author: ![pearlzli](https://avatars.discourse-cdn.com/v4/letter/p/76d3ee/32.png) [@pearlzli](https://discourse.julialang.org/u/pearlzli)
#### Post date: [June 25, 2018, 9:39pm UTC](https://discourse.julialang.org/t/rescuing-old-julia-0-5-nullable-date-type-in-0-6/11818/6 "2018-06-25T21:39:48Z")

</div>

I think I got your example to work when I did the following:

- Change the type of `rollup_date` in the `oldfoo5` definition to `OldNullable{Date}`
- Change the definition of `readas` on `oldfoo5` to  
`readas(x::oldfoo5) = foo5(x.id, JLD.readas(x.rollup_date))`

Does that work for you?

---

<div class="post-metadata">

### Author: ![acunningham](https://avatars.discourse-cdn.com/v4/letter/a/96bed5/32.png) [@acunningham](https://discourse.julialang.org/u/acunningham)
#### Post date: [June 26, 2018, 11:17am UTC](https://discourse.julialang.org/t/rescuing-old-julia-0-5-nullable-date-type-in-0-6/11818/7 "2018-06-26T11:17:17Z")

</div>

Yes, that works just fine. Never thought to try that.

Many thanks!

---

<div class="post-metadata">

### Author: ![acunningham](https://avatars.discourse-cdn.com/v4/letter/a/96bed5/32.png) [@acunningham](https://discourse.julialang.org/u/acunningham)
#### Post date: [July 23, 2018, 9:30pm UTC](https://discourse.julialang.org/t/rescuing-old-julia-0-5-nullable-date-type-in-0-6/11818/8 "2018-07-23T21:30:42Z")

</div>

So, I’ve encountered another issue with this. Reading in the old types works as suggested, however if I decide to create a new one and write it out, I can’t load it back in again. Have you encountered that?

So if you keep the existing code to “rescue” the old types but then create a new one and write it to disk. You’d can’t load it again. Same error then reappears.

Seems like the mapping to read `OldNullable` then causes in issue when trying to write out a regular `Nullable`.

However, i can load the type if I create a session and don’t include the mapping code.

```julia
new_foo = foo5(66, Date())

file_path = "C:\\new_foo.jld"

file_dir, file_name = splitdir(file_path)
file_prefix, file_ext = splitext(file_name)

JLD.save(file_path, file_prefix, new_foo, compress=false)

file_path = "C:\\new_foo.jld"
file_dir, file_name = splitdir(file_path)
file_prefix, file_ext = splitext(file_name)
obj = JLD.load(file_path, file_prefix)

stored type OldNullable{Base.Dates.Date} does not match currently loaded type

Stacktrace:
 [1] jldatatype(::JLD.JldFile, ::HDF5.HDF5Datatype) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\jld_types.jl:721
 [2] jldatatype(::JLD.JldFile, ::HDF5.HDF5Datatype) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\jld_types.jl:711
 [3] read(::JLD.JldDataset) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\JLD.jl:368
 [4] read(::JLD.JldFile, ::String) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\JLD.jl:344
 [5] (::JLD.##41#42{String})(::JLD.JldFile) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\JLD.jl:1241
 [6] #jldopen#11(::Array{Any,1}, ::Function, ::JLD.##41#42{String}, ::String, ::Vararg{String,N} where N) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\JLD.jl:243
 [7] load(::FileIO.File{FileIO.DataFormat{:JLD}}, ::String) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\JLD\src\JLD.jl:1240
 [8] #load#13(::Array{Any,1}, ::Function, ::String, ::String, ::Vararg{String,N} where N) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\FileIO\src\loadsave.jl:113
 [9] load(::String, ::String) at C:\Program Files\ReSolver.DistributedJulia\packages\v0.6\FileIO\src\loadsave.jl:113

```