Allow arbitrary number of arguments to submit

[blegat]

It would have zero argument for RejectSolution, see #782, it would be weird to require the user to provide a tuple()

[mlubin]

Wait, hold on. Aren't there MethodError concerns with this? How can JuMP expose this function and know that the caller is providing the correct number of arguments?

[blegat]

They will get an error like it's not supported:
https://github.com/JuliaOpt/MathOptInterface.jl/blob/e458dfd55b581d2c0470a69095ab0001df823d82/src/attributes.jl#L389-L395
We have the same issue for get:
https://github.com/JuliaOpt/MathOptInterface.jl/blob/e458dfd55b581d2c0470a69095ab0001df823d82/src/attributes.jl#L248-L250
But not for set, which throws a MethodError (but still violating the MethodError principle since it's not the same one but avoiding this causes ambiguity as mentioned in the comment):
https://github.com/JuliaOpt/MathOptInterface.jl/blob/e458dfd55b581d2c0470a69095ab0001df823d82/src/attributes.jl#L348-L376

[mlubin]

They will get an error like it's not supported:

If you try to submit using a submittable that's supported, then you'll hit throw(SubmitNotAllowed(sub)). This seems like the wrong error message, because submit may be allowed, you just submitted with the wrong number of arguments.

I don't see an easy workaround if we're following the MethodError principle.

We have the same issue for get

Is this an issue with the fallback or with the definition of get? Why do we need get to allow an arbitrary number of arguments?

[blegat]

Is this an issue with the fallback or with the definition of get? Why do we need get to allow an arbitrary number of arguments?

Not, just with the fallback.

[codecov-io]

Codecov Report

Merging #797 into master will not change coverage.
The diff coverage is 0%.

@@          Coverage Diff           @@
##           master    #797   +/-   ##
======================================
  Coverage    94.1%   94.1%           
======================================
  Files          59      59           
  Lines        6671    6671           
======================================
  Hits         6278    6278           
  Misses        393     393

Impacted Files	Coverage Δ
src/attributes.jl	85.54% <0%> (ø)	⬆️

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[blegat]

In fact, it does not make sense to throw SubmitNotAllowed in the fallback since for submittable you support iff you implement submit. It should throw an methoderror now
For set, it's different since you may support an attribute but only implement allocate/load.

[mlubin]

Not, just with the fallback.

What is preventing us from defining the fallback without using varargs?

[blegat]

What is preventing us from defining the fallback without using varargs?

Nothing, let's open an issue #799

[mlubin]

LGTM. Merge when ready.