Test case fails on julia 1.10

[NeroBlackstone]

In test/deser.jl, test case No.30:

https://github.com/bhftbootcamp/Serde.jl/blob/6140ed063b0c4b2e73d31a86152c6febbcdeba18/test/deser.jl#L501-L504

In julia 1.10, it will fail:

Case №30: Deserializing missing and nothing: Test Failed at /home/nero/github/Serde.jl/test/deser.jl:501
  Expression: Serde.deser(Foo35_3, Dict{String, Any}("value" => 100))
    Expected: "WrongType: for 'Foo35_3' value '100' has wrong type 'value::Int64', must be 'value::Missing'"
     Message: "cannot convert a value to missing for assignment"

Stacktrace:
 [1] macro expansion
   @ ~/github/Serde.jl/test/deser.jl:501 [inlined]
 [2] macro expansion
   @ ~/.julia/juliaup/julia-1.10.3+0.x64.linux.gnu/share/julia/stdlib/v1.10/Test/src/Test.jl:1577 [inlined]
 [3] macro expansion
   @ ~/github/Serde.jl/test/deser.jl:472 [inlined]
 [4] macro expansion
   @ ~/.julia/juliaup/julia-1.10.3+0.x64.linux.gnu/share/julia/stdlib/v1.10/Test/src/Test.jl:1577 [inlined]
 [5] top-level scope
   @ ~/github/Serde.jl/test/deser.jl:7

This is because Julia 1.10 throw a different Error in src/de/deser.jl:

https://github.com/bhftbootcamp/Serde.jl/blob/6140ed063b0c4b2e73d31a86152c6febbcdeba18/src/De/Deser.jl#L249-L251

If we test this function:

deser(Missing,100)

Julia 1.10 will throw ERROR: cannot convert a value to missing for assignment

Julia 1.8 will throw ERROR: MethodError: convert(::Type{Union{}}, ::Int64) is ambiguous. Candidates

And in src/de/deser.jl, we are not handling ErrorException.

https://github.com/bhftbootcamp/Serde.jl/blob/6140ed063b0c4b2e73d31a86152c6febbcdeba18/src/De/Deser.jl#L494-L515

Question

How do you think it can be improved better? I can open a PR.

[NeroBlackstone]

A similar julia 1.10 test fail is No.37 in same test file.

Case №37: Deserialization Number to Number: Test Failed at /home/nero/github/Serde.jl/test/deser.jl:662
  Expression: Serde.deser_json(Message{Nothing}, exp_str)
    Expected: "WrongType: for 'Message{Nothing}' value 'Dict{String, Any}()' has wrong type 'payload::Dict{String, Any}', must be 'payload::Nothing'"
     Message: "cannot convert a value to nothing for assignment"

Stacktrace:
 [1] macro expansion
   @ ~/github/Serde.jl/test/deser.jl:662 [inlined]
 [2] macro expansion
   @ ~/.julia/juliaup/julia-1.10.3+0.x64.linux.gnu/share/julia/stdlib/v1.10/Test/src/Test.jl:1577 [inlined]
 [3] macro expansion
   @ ~/github/Serde.jl/test/deser.jl:655 [inlined]
 [4] macro expansion
   @ ~/.julia/juliaup/julia-1.10.3+0.x64.linux.gnu/share/julia/stdlib/v1.10/Test/src/Test.jl:1577 [inlined]
 [5] top-level scope
   @ ~/github/Serde.jl/test/deser.jl:7

[dmitrii-doronin]

Hi, @NeroBlackstone! I've seen this issue before and I have not been able to pinpoint the root cause. If you do plain conversion, outside of the package, it will work just fine. This behaviour sprung up after 1.10 release.

Currently it tries to convert after return (there's a specific syntax for that). I think, the solution would be to switch to explicit conversion within functions before return.

[NeroBlackstone]

I find the reason, convert() throws inconsistent errors in Julia 1.10.

I think the simplest solution is:

elseif (e isa MethodError) || (e isa InexactError) || (e isa ArgumentError) || (e isa ErrorException)

I have tested it and all passed, what do you think?

[dmitrii-doronin]

Have you tried explicit conversions? I think it might take more time but be more sustainable in the long run.

Also I'm baffled by the policy. It's not julia 2.0 to break existing error behaviours)

[dmitrii-doronin]

Also, @gryumov what's your stand on this? Apparently, there's an issue already on the official page.

[NeroBlackstone]

Also I'm baffled by the policy. It's not julia 2.0 to break existing error behaviours)

“Error types, unless explicitly documented (like DomainError or Base.IOError), are subject to change is the official policy”

Looks like they don't think this is a break change.😅

I don’t know if subsequent Julia versions will maintain this behavior.

[NeroBlackstone]

I think, the solution would be to switch to explicit conversion within functions before return.

Sorry, I don't quite understand what you are describing here. Do you mean to explicitly call the convert function to convert Any type to Missing before the derse function returns?

Or define a new convert function to throw MethodError ?

[dmitrii-doronin]

Okay, I see where the issue is. I'm taking a look. You can comment out these tests if you're actively developing. They don't affect the core functionality.

[gryumov]

Hello everyone! @dmitrii-doronin it might seem strange #40, but we need to deal with multiple dispatch, let's create issues for this:

https://github.com/bhftbootcamp/Serde.jl/actions/runs/8912634371/job/24476466918?pr=40