More robust blockreshape

Author: mtfishman

Project.toml

@@ -1,7 +1,7 @@
 name = "BlockSparseArrays"
 uuid = "2c9a651f-6452-4ace-a6ac-809f4280fbb4"
 authors = ["ITensor developers <support@itensor.org> and contributors"]
-version = "0.9.1"
+version = "0.9.2"
 
 [deps]
 Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"

src/BlockArraysExtensions/BlockArraysExtensions.jl

@@ -277,7 +277,13 @@ function _blockreshape(a::AbstractArray, axes::Tuple{Vararg{AbstractUnitRange}})
     # TODO: Better converter here.
     return reshape(reshaped_blocks_a[I], block_axes_I)
   end
-  bs = Dict(Block(Tuple(I)) => f(I) for I in eachstoredindex(reshaped_blocks_a))
+  bs = if iszero(storedlength(reshaped_blocks_a))
+    # This branch only seems to be required in Julia 1.10, not Julia 1.11.
+    # TODO: Remove this branch once Julia 1.10 support is dropped.
+    Dict{Block{length(axes),Int},AbstractArray{eltype(a),length(axes)}}()
+  else
+    Dict(Block(Tuple(I)) => f(I) for I in eachstoredindex(reshaped_blocks_a))
+  end
   return blocksparse(bs, axes)
 end