fix mapreduce

Author: JoshuaLampert

lib/RecursiveArrayToolsRaggedArrays/src/RecursiveArrayToolsRaggedArrays.jl

@@ -1521,7 +1521,11 @@ end
 Base.map(f, A::AbstractRaggedVectorOfArray) = map(f, A.u)
 
 function Base.mapreduce(f, op, A::AbstractRaggedVectorOfArray; kwargs...)
-    return mapreduce(f, op, view(A, ntuple(_ -> :, ndims(A))...); kwargs...)
+    # For full reduction (no kwargs): safely recurse over u to handle ragged inner shapes.
+    # The view-based approach uses size(A.u[1]) for all columns, which fails when inner
+    # arrays are themselves ragged with different column counts.
+    isempty(kwargs) || return mapreduce(f, op, view(A, ntuple(_ -> :, ndims(A))...); kwargs...)
+    return mapreduce(u -> mapreduce(f, op, u), op, A.u)
 end
 function Base.mapreduce(
         f, op, A::AbstractRaggedVectorOfArray{T, 1, <:AbstractVector{T}}; kwargs...

lib/RecursiveArrayToolsRaggedArrays/test/runtests.jl

@@ -1016,4 +1016,15 @@ using Test
         src[:, 1] .= 99.0
         @test dst[:, 1] == [1.0, 1.0]
     end
+
+    @testset "mapreduce over nested ragged arrays" begin
+        # Outer array whose inner RaggedVoA elements have different column counts.
+        # mapreduce must recurse over A.u rather than building a fixed-shape view.
+        inner1 = RaggedVectorOfArray([ones(3), ones(3)])           # 2 columns
+        inner2 = RaggedVectorOfArray([ones(3), ones(3), ones(3)])  # 3 columns — ragged!
+        u = RaggedVectorOfArray([inner1, inner2])
+
+        @test mapreduce(identity, +, u) == 15.0  # (2+3)*3
+    end
+
 end