MOI optimizer broke

[blegat]

It seems the constructor NLPModelsJuMP.Optimizer() broke with an update of one of the dependencies. When running the tests, I get

Got exception outside of a @test
  MethodError: no method matching SolverCore.GenericExecutionStats{Float64, Vector{Float64}, Vector{Float64}, Any}()
  
  Closest candidates are:
    (::Type{SolverCore.GenericExecutionStats{T, S, V, Tsp}} where {T, S, V, Tsp})(::Any, ::Any, ::Any, ::Any, ::Any, ::Any, ::Any, ::Any, ::Any, ::Any, ::Any, ::Any, ::Any, ::Any, ::Any, ::Any, ::Any, ::Any, ::Any, ::Any, ::Any)
     @ SolverCore ~/.julia/packages/SolverCore/iOwNg/src/stats.jl:109
  
  Stacktrace:
    [1] NLPModelsJuMP.Optimizer()
      @ NLPModelsJuMP ~/.julia/dev/NLPModelsJuMP/src/MOI_wrapper.jl:10

The versions used are

(NLPModelsJuMP) pkg> st
Project NLPModelsJuMP v0.12.1
Status `~/.julia/dev/NLPModelsJuMP/Project.toml`
  [4076af6c] JuMP v1.15.1
  [b8f27783] MathOptInterface v1.20.1
  [a4795742] NLPModels v0.20.0
  [01435c0c] Percival v0.7.0
  [ff4d7338] SolverCore v0.3.7
  [37e2e46d] LinearAlgebra
  [de0858da] Printf
  [2f01184e] SparseArrays

[blegat]

This is why it was not detected in the tests: #167 (comment)

[tmigot]

Ok... I am slighly surprised it ever worked now as I don't remember the last we updated the GenericExecutionStats constructor. The main one being:

 stats = GenericExecutionStats(nlp)

because it allocates some structure that are dependent of the size of the problem.

The solution might be to proceed in the same way we handle the solver?

It should be possible to make an empty constructor for the GenericExecutionStats, but it will at minima requires knowing the type used for the solution vector and the multipliers (for instance, Vector{Float64}, etc...).

[blegat]

Ok thanks, #168 should fix it by simply using nothing.

[amontoison]

Do you want a new release?

[blegat]

Yes please :)

[amontoison]

Ok, I will do it later today 👍

@tmigot Do you plan to open a PR with your new empty GenericStatsExectution that you added in SolverCore.jl?

[tmigot]

Thanks @amontoison , I will add it later, no rush there.