fix combine_blockaxes

NDTensors/src/lib/BlockSparseArrays/ext/BlockSparseArraysGradedAxesExt/test/runtests.jl

@@ -39,6 +39,8 @@ const elts = (Float32, Float64, Complex{Float32}, Complex{Float64})
     d2 = gradedrange([U1(0) => 2, U1(1) => 2])
     a = BlockSparseArray{elt}(d1, d2, d1, d2)
     blockdiagonal!(randn!, a)
+    @test axes(a, 1) isa GradedOneTo
+    @test axes(view(a, 1:4, 1:4), 1) isa GradedOneTo
 
     for b in (a + a, 2 * a)
       @test size(b) == (4, 4, 4, 4)

NDTensors/src/lib/GradedAxes/src/gradedunitrange.jl

@@ -17,7 +17,8 @@ using BlockArrays:
   blocklengths,
   findblock,
   findblockindex,
-  mortar
+  mortar,
+  sortedunion
 using Compat: allequal
 using FillArrays: Fill
 using ..LabelledNumbers:
@@ -304,17 +305,25 @@ end
 # that mixed dense and graded axes.
 # TODO: Maybe come up with a more general solution.
 function BlockArrays.combine_blockaxes(
-  a1::GradedOneTo{<:LabelledInteger{T}}, a2::Base.OneTo{T}
+  a1::AbstractGradedUnitRange{T}, a2::Base.OneTo{T}
 ) where {T<:Integer}
   combined_blocklasts = sort!(union(unlabel.(blocklasts(a1)), blocklasts(a2)))
   return BlockedOneTo(combined_blocklasts)
 end
 function BlockArrays.combine_blockaxes(
-  a1::Base.OneTo{T}, a2::GradedOneTo{<:LabelledInteger{T}}
+  a1::Base.OneTo{T}, a2::AbstractGradedUnitRange{T}
 ) where {T<:Integer}
   return BlockArrays.combine_blockaxes(a2, a1)
 end
 
+# preserve labels inside combine_blockaxes
+# TODO dual
+function BlockArrays.combine_blockaxes(
+  a::AbstractGradedUnitRange, b::AbstractGradedUnitRange
+)
+  return gradedrange(sortedunion(blocklasts(a), blocklasts(b)))
+end
+
 # Version of length that checks that all blocks have the same label
 # and returns a labelled length with that label.
 function labelled_length(a::AbstractBlockVector{<:Integer})