[BUG] `fusedims` on `BlockSparseArray` with `gradedrange` axes and trailing singleton broken

[mtfishman]

For example:

using BlockSparseArrays: BlockSparseVector
using GradedUnitRanges: gradedrange
using SymmetrySectors: U1
using TensorAlgebra: blockedperm, fusedims

r = gradedrange([U1(0) => 2, U1(1) => 2])
a = BlockSparseVector{Float64}(undef, r)
b = fusedims(a, blockedperm((1,), ()))

throws the error:

LoadError: StackOverflowError:
Stacktrace:
     [1] unchecked_oneto
       @ ./range.jl:472 [inlined]
     [2] map
       @ ./tuple.jl:355 [inlined]
     [3] axes
       @ ./abstractarray.jl:98 [inlined]
     [4] to_indices(A::Base.OneTo{Int64}, I::Tuple{BlockArrays.BlockVector{BlockArrays.Block{1, Int64}, Vector{Vector{BlockArrays.Block{1, Int64}}}, Tuple{BlockArrays.BlockedOneTo{Int64, Vector{Int64}}}}})
       @ BlockArrays ~/.julia/packages/BlockArrays/8VbzB/src/views.jl:58
     [5] getindex(A::Base.OneTo{Int64}, I::BlockArrays.BlockVector{BlockArrays.Block{1, Int64}, Vector{Vector{BlockArrays.Block{1, Int64}}}, Tuple{BlockArrays.BlockedOneTo{Int64, Vector{Int64}}}})
       @ Base ./abstractarray.jl:1312
     [6] unblock(A::Base.OneTo{Int64}, inds::Tuple{Base.OneTo{Int64}}, I::Tuple{BlockArrays.BlockVector{BlockArrays.Block{1, Int64}, Vector{Vector{BlockArrays.Block{1, Int64}}}, Tuple{BlockArrays.BlockedOneTo{Int64, Vector{Int64}}}}})
       @ BlockArrays ~/.julia/packages/BlockArrays/8VbzB/src/views.jl:10
     [7] to_indices(A::Base.OneTo{Int64}, inds::Tuple{Base.OneTo{Int64}}, I::Tuple{BlockArrays.BlockVector{BlockArrays.Block{1, Int64}, Vector{Vector{BlockArrays.Block{1, Int64}}}, Tuple{BlockArrays.BlockedOneTo{Int64, Vector{Int64}}}}})
       @ BlockArrays ~/.julia/packages/BlockArrays/8VbzB/src/views.jl:35
--- the above 4 lines are repeated 19994 more times ---
 [79984] to_indices(A::Base.OneTo{Int64}, I::Tuple{BlockArrays.BlockVector{BlockArrays.Block{1, Int64}, Vector{Vector{BlockArrays.Block{1, Int64}}}, Tuple{BlockArrays.BlockedOneTo{Int64, Vector{Int64}}}}})
       @ BlockArrays ~/.julia/packages/BlockArrays/8VbzB/src/views.jl:58
 [79985] getindex(A::Base.OneTo{Int64}, I::BlockArrays.BlockVector{BlockArrays.Block{1, Int64}, Vector{Vector{BlockArrays.Block{1, Int64}}}, Tuple{BlockArrays.BlockedOneTo{Int64, Vector{Int64}}}})
       @ Base ./abstractarray.jl:1312
 [79986] unblock(A::Base.OneTo{Int64}, inds::Tuple{Base.OneTo{Int64}}, I::Tuple{BlockArrays.BlockVector{BlockArrays.Block{1, Int64}, Vector{Vector{BlockArrays.Block{1, Int64}}}, Tuple{BlockArrays.BlockedOneTo{Int64, Vector{Int64}}}}})
       @ BlockArrays ~/.julia/packages/BlockArrays/8VbzB/src/views.jl:10

with versions:

  [2c9a651f] BlockSparseArrays v0.2.20
  [e2de450a] GradedUnitRanges v0.1.6
  [f8a8ad64] SymmetrySectors v0.1.5
  [68bd88dc] TensorAlgebra v0.1.10

[mtfishman]

@ogauthe maybe related to ITensor/TensorAlgebra.jl#33.

[ogauthe]

To trigger the issue with the latest TensorAlgebra, one needs to use bp = permmortar(((1,), ())). The issue is still there.

[ogauthe]

Fixed by the replacement of fusedims with matricize