Select outputs after creating an edge to size stack at position other than last fails

[DrChainsaw]

Root cause is that variable array for selecting existing outputs can only select from previous existing outputs.

The logic to deal with this in inoutconstraint!(s, ::SizeStack, v, model, vardict::Dict) assumes that any misaligned inputs are last in inputs(v).

It might be possible to avoid aligning select vars but do align insertion vars as they can be assumed to have the same size. MWE below fails to align sizes and reverts the edge addition when this change is made though.

MWE testset which runs in select.jl:

    @testset "Create edge to SizeStack pos 1" begin
        inpt = iv(3)
        v1 = av(inpt, 2, "v1")
        v2 = av(inpt, 3, "v2")
        v3 = cc(v1, name="v3")
        v4 = av(v3, 3, "v4")

        g = CompGraph(inpt, v3)
        @test size(g(ones(Float32, 1,3))) == (1, nout(v3))

        create_edge!(v2, v3, pos=1)
        Δoutputs(v3, v -> 1:nout_org(v))

        @test in_inds(op(v4)) == [-1,-1,-1,1,2]

        @test size(g(ones(Float32, 1,3))) == (1, nout(v3))
    end

[DrChainsaw]

Testcase for structure (where it belongs):

@testset "Create edge to SizeStack pos 1" begin
    v0 = inpt(3, "v0")
    v1 = av(v0, 2; name="v1")
    v2 = av(v0, 3, name="v2")
    v3 = conc(v1; dims=2, traitdecoration=tf("v3"))
    v4 = av(v3, 3, name="v4")

    g = CompGraph(v0, v3)
    @test size(g(ones(3))) == (nout(v3),1)

    @test create_edge!(v2, v3, pos=1)

    @test lastins(v4) == [-1,-1,-1,1,2]

    @test size(g(ones(3))) == (nout(v3),1)
end