Add tests with JET

[devmotion]

Based on and opened against #954.

The most basic JET tests revealed a typo and few issues (calls of non-existing methods):

julia> using StatsBase, JET

julia> report_package(StatsBase; target_defined_modules = true)
...
═════ 6 possible errors found ═════
┌ _unscaled_covzm(x::DenseMatrix, dims::Colon) @ StatsBase /Users/david/.julia/packages/StatsBase/uvhDX/src/cov.jl:26
│ no matching method found `unscaled_covzm(::DenseMatrix)`: StatsBase.unscaled_covzm(x::DenseMatrix)
└────────────────────
┌ _unscaled_covzm(x::DenseMatrix, wv::StatsBase.AbstractWeights, dims::Colon) @ StatsBase /Users/david/.julia/packages/StatsBase/uvhDX/src/cov.jl:29
│ no matching method found `_scalevars(::DenseMatrix, ::StatsBase.AbstractWeights)`: StatsBase._scalevars(x::DenseMatrix, wv::StatsBase.AbstractWeights)
└────────────────────
┌ (::Base.TTY)(obj::StatisticalModel) @ StatsBase /Users/david/.julia/packages/StatsBase/uvhDX/src/deprecates.jl:8
│ `StatsBase.MethodErrror` is not defined: StatsBase.MethodErrror
└────────────────────
┌ model_response(obj::StatisticalModel) @ StatsBase ./deprecated.jl:105
│ no matching method found `response(::StatisticalModel)`: response(obj::StatisticalModel)
└────────────────────
┌ scattermat_zm(x::DenseMatrix, dims::Int64) @ StatsBase ./deprecated.jl:105
│ no matching method found `kwcall(::@NamedTuple{dims::Int64}, ::typeof(StatsBase.scattermat_zm), ::DenseMatrix)`: Core.kwcall(NamedTuple{(:dims,)}(tuple(dims::Int64)::Tuple{Int64})::@NamedTuple{dims::Int64}, scattermat_zm, x::DenseMatrix)
└────────────────────
┌ scattermat_zm(x::DenseMatrix, wv::StatsBase.AbstractWeights, dims::Int64) @ StatsBase ./deprecated.jl:105
│ no matching method found `kwcall(::@NamedTuple{dims::Int64}, ::typeof(StatsBase.scattermat_zm), ::DenseMatrix, ::StatsBase.AbstractWeights)`: Core.kwcall(NamedTuple{(:dims,)}(tuple(dims::Int64)::Tuple{Int64})::@NamedTuple{dims::Int64}, scattermat_zm, typeassert(x::DenseMatrix, StatsBase.DenseMatrix)::DenseMatrix, typeassert(wv::StatsBase.AbstractWeights, AbstractWeights)::StatsBase.AbstractWeights)
└────────────────────

Edit: Tests currently fail on 1.12 (only somewhat experimental support for JET, an internal AssertionError is thrown) and on the other Julia versions since JET triggers method redefinitions (e.g. https://github.com/JuliaStats/StatsBase.jl/actions/runs/14743207189/job/41385529150?pr=955#step:6:178) that cause other subsequent tests to fail. See https://aviatesk.github.io/JET.jl/v0.9/jetanalysis/#jetanalysis-toplevel-entry

Edit 2: "Fixed" by disabling JET tests on Julia 1.12 and moving the JET tests to the end, after all other tests.

[devmotion]

There exists no unscaled_covzm with this type signature in Statistics.

[devmotion]

Same here.

[devmotion]

A typo.

[devmotion]

Also these do not exist.

[nalimilan]

JET makes tests fail due to version compat issues at #959. Any ideas what may be going on?

[devmotion]

It seems to be a bug in Pkg: #959 (comment)