do not reshape during widening (#246)

* do not reshape during widening

* bump project file

Author: piever

Project.toml

@@ -1,6 +1,6 @@
 name = "StructArrays"
 uuid = "09ab397b-f2b6-538f-b94a-2f83cf4a842a"
-version = "0.6.12"
+version = "0.6.13"
 
 [deps]
 Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"

src/collect.jl

@@ -122,9 +122,9 @@ _widenstructarray(dest::AbstractArray, i, ::Type{T}) where {T} = _widenarray(des
 
 _widenarray(dest::AbstractArray{T}, i, ::Type{T}) where {T} = dest
 function _widenarray(dest::AbstractArray, i, ::Type{T}) where T
-    new = similar(dest, T, length(dest))
+    new = similar(dest, T)
     copyto!(new, firstindex(new), dest, firstindex(dest), i-1)
-    new
+    return new
 end
 
 """

test/runtests.jl

@@ -817,11 +817,19 @@ pair_structarray((first, last)) = StructArray{Pair{eltype(first), eltype(last)}}
 end
 
 @testset "collect2D" begin
-    s = (l for l in [(a=i, b=j) for i in 1:3, j in 1:4])
+    s = ((a=i, b=j) for i in 1:3, j in 1:4)
     v = collect_structarray(s)
     @test size(v) == (3, 4)
+    @test eltype(v) == @NamedTuple{a::Int, b::Int}
     @test v.a == [i for i in 1:3, j in 1:4]
     @test v.b == [j for i in 1:3, j in 1:4]
+
+    s = (i == 1 ? (a=nothing, b=j) : (a=i, b=j) for i in 1:3, j in 1:4)
+    v = collect_structarray(s)
+    @test size(v) == (3, 4)
+    @test eltype(v) == @NamedTuple{a::Union{Int, Nothing}, b::Int}
+    @test v.a == [i == 1 ? nothing : i for i in 1:3, j in 1:4]
+    @test v.b == [j for i in 1:3, j in 1:4]
 end
 
 @testset "collectoffset" begin