oneunit of sparse matrix should return sparse matrix

[KlausC]

currently we have:

julia> oneunit(sparse([1 1 ; 2 2]))
2×2 Array{Int64,2}:
 1  0
 0  1
julia> one(sparse([1 1 ; 2 2]))
2×2 SparseMatrixCSC{Int64,Int64} with 2 stored entries:
  [1, 1]  =  1
  [2, 2]  =  1

where it should be. I think the behavour of one is as it should be, while oneunit is inconsistent.

julia> oneunit(sparse([1 2; 3 4]))
2×2 SparseMatrixCSC{Int64,Int64} with 2 stored entries:
  [1, 1]  =  1
  [2, 2]  =  1

julia> one(sparse([1 2; 3 4]))
2×2 SparseMatrixCSC{Int64,Int64} with 2 stored entries:
  [1, 1]  =  1
  [2, 2]  =  1

[JeffBezanson]

Bumping for review. LGTM.

[ararslan]

This has already been backported to 1.1.0 and cannot be backported to 1.0 as a minor change.

[ViralBShah]

May I request not labelling this as a minor change and allowing it backported to 1.0? My only reason is that we are backporting a number of other sparse PRs that are small changes, but together greatly improve the overall quality of the sparse libraries.

There is no urgency, but it would be nice to get it into the 1.0.x at some point.

[KristofferC]

We should backport bugfixes, doc improvements and performance improvements to patch releases. Since we are aiming to do 4 month releases it is not too bad if a small change like this goes into the next minor release imo.

[ViralBShah]

I guess that is ok - even though this is probably a borderline bugfix. So folks who want LTS (the 1.0 branch) will not get this and have to wait for the next LTS.

[KristofferC]

So folks who want LTS (the 1.0 branch) will not get this and have to wait for the next LTS.

Yes, but the reason you are on an LTS in the first place likely because you don't want these type of changes until you decide to upgrade to a new minor version.