Fix RaggedEnd in range and returning DiffEqArray

[JoshuaLampert]

Checklist

• Appropriate tests were added
• Any code changes were done in a way that does not break public API
• All documentation related to code changes were updated
• The new code follows the
  contributor guidelines, in particular the SciML Style Guide and
  COLPRAC.
• Any new documentation only uses public API

Additional context

This fixes two issues:

1. Indexing with a range, which has a start including an end fails (noticed by @iago-lito on Zulip):
   on master:

julia> u = VectorOfArray([[1.0, 2.0, 3.0], [4.0, 5.0, 6.0], [7.0, 8.0, 9.0]])
VectorOfArray{Float64,2}:
3-element Vector{Vector{Float64}}:
 [1.0, 2.0, 3.0]
 [4.0, 5.0, 6.0]
 [7.0, 8.0, 9.0]

julia> u[:, end-1:end]
ERROR: MethodError: no method matching isless(::RecursiveArrayTools.RaggedEnd, ::RecursiveArrayTools.RaggedEnd)
The function `isless` exists, but no method is defined for this combination of argument types.

Closest candidates are:
  isless(::Missing, ::Any)
   @ Base missing.jl:87
  isless(::Any, ::Missing)
   @ Base missing.jl:88
  isless(::Pkg.Resolve.VersionWeight, ::Pkg.Resolve.VersionWeight)
   @ Pkg ~/.julia/juliaup/julia-1.12.4+0.x64.linux.gnu/share/julia/stdlib/v1.12/Pkg/src/Resolve/versionweights.jl:28
  ...

Stacktrace:
 [1] <(x::RecursiveArrayTools.RaggedEnd, y::RecursiveArrayTools.RaggedEnd)
   @ Base ./operators.jl:399
 [2] <=(x::RecursiveArrayTools.RaggedEnd, y::RecursiveArrayTools.RaggedEnd)
   @ Base ./operators.jl:448
 [3] >=(x::RecursiveArrayTools.RaggedEnd, y::RecursiveArrayTools.RaggedEnd)
   @ Base ./operators.jl:472
 [4] (::Colon)(start::RecursiveArrayTools.RaggedEnd, stop::RecursiveArrayTools.RaggedEnd)
   @ Base ./range.jl:7
 [5] top-level scope
   @ REPL[6]:1

This PR:

julia> u = VectorOfArray([[1.0, 2.0, 3.0], [4.0, 5.0, 6.0], [7.0, 8.0, 9.0]])
VectorOfArray{Float64,2}:
3-element Vector{Vector{Float64}}:
 [1.0, 2.0, 3.0]
 [4.0, 5.0, 6.0]
 [7.0, 8.0, 9.0]

julia> u[:, end-1:end]
VectorOfArray{Float64,2}:
2-element Vector{Vector{Float64}}:
 [4.0, 5.0, 6.0]
 [7.0, 8.0, 9.0]

2. Indexing a DiffEqArray with a range returned a VectorOfArray instead of a DiffEqArray:
   on master:

julia> u = DiffEqArray([[1.0, 2.0, 3.0], [4.0, 5.0, 6.0], [7.0, 8.0, 9.0]], 1:3)
t: 1:3
u: 3-element Vector{Vector{Float64}}:
 [1.0, 2.0, 3.0]
 [4.0, 5.0, 6.0]
 [7.0, 8.0, 9.0]

julia> u[:, 2:end]
VectorOfArray{Float64,2}:
2-element Vector{Vector{Float64}}:
 [4.0, 5.0, 6.0]
 [7.0, 8.0, 9.0]

This PR:

julia> u = DiffEqArray([[1.0, 2.0, 3.0], [4.0, 5.0, 6.0], [7.0, 8.0, 9.0]], 1:3)
t: 1:3
u: 3-element Vector{Vector{Float64}}:
 [1.0, 2.0, 3.0]
 [4.0, 5.0, 6.0]
 [7.0, 8.0, 9.0]

julia> u[:, 2:end]
t: 2:1:3
u: 2-element Vector{Vector{Float64}}:
 [4.0, 5.0, 6.0]
 [7.0, 8.0, 9.0]

[ChrisRackauckas]

You're missing start with raggedend and stop with integer?

[JoshuaLampert]

Oh, right. That's also possible. I'll add that in a minute.

[JoshuaLampert]

Should be fixed. Thanks for catching that!

[JoshuaLampert]

This was actually pretty confusing because in the previous test t of the left hand side is not the same as the t on the right hand side, but it is not caught because of

RecursiveArrayTools.jl/src/vector_of_array.jl

Line 1048 in 6519ecf

return A.u == B.u

.

[JoshuaLampert]

Can this be merged, @ChrisRackauckas?