Add Aqua.jl for some static testing

[lgoettgens]

See oscar-system/Oscar.jl#2385.

[lgoettgens]

When reviewing this PR, please check the compat versions introduced here for sensibility.

[benlorenz]

A few more changes:

• Adjusted the compat bounds a little bit (see commit messages for details).
• Removed one case of type piracy which did come from this repository.
• Improved comments for the disabled tests.

For type piracy we basically have these two (for various kinds of containers):

[5] isempty(arg1::Union{Ptr{Nothing}, CxxWrap.CxxWrapCore.ConstCxxPtr{<:Polymake.Set{Int64}}, CxxWrap.CxxWrapCore.CxxPtr{<:Polymake.Set{Int64}}}) in Polymake at /home/lorenz/.julia/packages/CxxWrap/aXNBY/src/CxxWrap.jl:624
[6] length(arg1::Union{Ptr{Nothing}, CxxWrap.CxxWrapCore.ConstCxxPtr{<:Polymake.Map{CxxWrap.StdLib.StdString, CxxWrap.StdLib.StdString}}, CxxWrap.CxxWrapCore.CxxPtr{<:Polymake.Map{CxxWrap.StdLib.StdString, CxxWrap.StdLib.StdString}}}) in Polymake at /home/lorenz/.julia/packages/CxxWrap/aXNBY/src/CxxWrap.jl:624

Unless someone wants to dig into how CxxWrap generates these signatures this will stay disabled.

Ambiguities is somewhat similar except that there are thousands instead of just 40 cases and Aqua doesn't seem to provide any way to work with the results (which are just dumped on the screen...).

[lgoettgens]

Thanks for your changes!
For ambiguities, you could change the =false to =(recursive=false,) to only consider ambiguities that arise from at least one method contained in Polymake.jl. Maybe this then ignores most of the CxxWrap stuff and leaves only some few things to fix.

The Aqua-function is basically only a wrapper around Test.detect_ambiguities
https://github.com/JuliaTesting/Aqua.jl/blob/76443b2f5e52fed5b9354305af7cd32883ada15e/src/ambiguities.jl#L180

I think this would be the way to go and investigate.

If there are some certain functions with ambiguities coming from CxxWrap, one could disable those in the Aqua check (cf. exclude in https://juliatesting.github.io/Aqua.jl/dev/#Aqua.test_ambiguities-Tuple{Any}).

[benlorenz]

recursive=false doesn't seem to change anything, probably because these are functions that are generated inside Polymake.jl (we write some c++ code for these in libpolymake_julia and when Polymake.jl is loaded this compiled c++ code is turned, by CxxWrap, into julia functions).

If anyone wants to look into this, a lot of the output looks like this (again with varying types), but there are also a bunch of other function names involved:

Ambiguity #23384
__delete(arg1::Union{Ptr{Nothing}, CxxWrap.CxxWrapCore.CxxPtr{<:CxxWrap.StdLib.UniquePtr{CxxWrap.CxxWrapCore.CxxBool}}}) in CxxWrap.StdLib at /home/lorenz/.julia/packages/CxxWrap/aXNBY/src/CxxWrap.jl:624
__delete(arg1::Union{Ptr{Nothing}, CxxWrap.CxxWrapCore.CxxPtr{<:Polymake.IncidenceMatrix{Polymake.Symmetric}}}) in Polymake at /home/lorenz/.julia/packages/CxxWrap/aXNBY/src/CxxWrap.jl:624

Possible fix, define
  __delete(::Union{Ptr{Nothing}, CxxWrap.CxxWrapCore.CxxPtr{Union{}}})

For now I will just keep piracy and ambiguities checks disabled.

Warning (for anyone trying to look into this): That ambiguities check might take about half an hour.