BoundsError on join

[MaximilianJHuber]

On JuliaDB 0.12 and IndexedTables 0.12:

using JuliaDB, Dates

t1 = table((date = [Date(2008,12,31), Date(2009,12,31), Date(2010,12,31)], ))
t2 = table((date = [Date(2008,12,31), Date(2009,12,31)], value = [1,2]))

join(t1, t2, how = :left, lkey = :date, rkey = :date)

throws:

BoundsError: attempt to access StructArrays.StructArray{NamedTuple{(),Tuple{}},1,NamedTuple{(),Tuple{}}} with indices 1:0 at index [1]

Stacktrace:
 [1] throw_boundserror(::StructArrays.StructArray{NamedTuple{(),Tuple{}},1,NamedTuple{(),Tuple{}}}, ::Tuple{Int64}) at .\abstractarray.jl:484
 [2] checkbounds at .\abstractarray.jl:449 [inlined]
 [3] macro expansion at C:\Users\Max\.julia\packages\StructArrays\Du4zZ\src\structarray.jl:125 [inlined]
 [4] getindex at C:\Users\Max\.julia\packages\StructArrays\Du4zZ\src\structarray.jl:122 [inlined]
 [5] #261 at .\none:0 [inlined]
 [6] iterate at .\generator.jl:47 [inlined]
 [7] _piterate at .\iterators.jl:814 [inlined]
 [8] _piterate at .\iterators.jl:816 [inlined]
 [9] iterate at .\iterators.jl:822 [inlined]
 [10] iterate at .\generator.jl:44 [inlined]
 [11] foreach(::getfield(IndexedTables, Symbol("##265#275")){NamedTuple{(),Tuple{}},NamedTuple{(:value,),Tuple{Union{Missing, Int64}}},NamedTuple{(:date,),Tuple{Date}},StructArrays.StructArray{NamedTuple{(:date,),Tuple{Date}},1,NamedTuple{(:date,),Tuple{Array{Date,1}}}},NamedTuple{(:left, :right),Tuple{StructArrays.StructArray{NamedTuple{(),Tuple{}},1,NamedTuple{(),Tuple{}}},StructArrays.StructArray{NamedTuple{(:value,),Tuple{Union{Missing, Int64}}},1,NamedTuple{(:value,),Tuple{Array{Union{Missing, Int64},1}}}}}}}, ::Base.Generator{Base.Iterators.ProductIterator{Tuple{Base.Generator{UnitRange{Int64},getfield(IndexedTables, Symbol("##262#272")){StructArrays.StructArray{NamedTuple{(:value,),Tuple{Union{Missing, Int64}}},1,NamedTuple{(:value,),Tuple{Array{Int64,1}}}},Array{Int64,1}}},Base.Generator{UnitRange{Int64},getfield(IndexedTables, Symbol("##261#271")){StructArrays.StructArray{NamedTuple{(),Tuple{}},1,NamedTuple{(),Tuple{}}},Array{Int64,1}}}}},typeof(reverse)}) at .\abstractarray.jl:1835
 [12] (::getfield(IndexedTables, Symbol("#iterate_value_push_key#270")){NamedTuple{(),Tuple{}},NamedTuple{(:value,),Tuple{Union{Missing, Int64}}},false,DataType,Nothing,Nothing,StructArrays.StructArray{NamedTuple{(:date,),Tuple{Date}},1,NamedTuple{(:date,),Tuple{Array{Date,1}}}},NamedTuple{(:left, :right),Tuple{StructArrays.StructArray{NamedTuple{(),Tuple{}},1,NamedTuple{(),Tuple{}}},StructArrays.StructArray{NamedTuple{(:value,),Tuple{Union{Missing, Int64}}},1,NamedTuple{(:value,),Tuple{Array{Union{Missing, Int64},1}}}}}},typeof(IndexedTables.concat_tup),StructArrays.StructArray{NamedTuple{(),Tuple{}},1,NamedTuple{(),Tuple{}}},StructArrays.StructArray{NamedTuple{(:value,),Tuple{Union{Missing, Int64}}},1,NamedTuple{(:value,),Tuple{Array{Int64,1}}}},StructArrays.StructArray{NamedTuple{(:date,),Tuple{Date}},1,NamedTuple{(:date,),Tuple{Array{Date,1}}}},StructArrays.StructArray{NamedTuple{(:date,),Tuple{Date}},1,NamedTuple{(:date,),Tuple{Array{Date,1}}}},Array{Int64,1},Array{Int64,1},Bool,Bool})(::Tuple{UnitRange{Int64},UnitRange{Int64}}) at C:\Users\Max\.julia\packages\IndexedTables\DgX0A\src\join.jl:62
 [13] foreach(::getfield(IndexedTables, Symbol("#iterate_value_push_key#270")){NamedTuple{(),Tuple{}},NamedTuple{(:value,),Tuple{Union{Missing, Int64}}},false,DataType,Nothing,Nothing,StructArrays.StructArray{NamedTuple{(:date,),Tuple{Date}},1,NamedTuple{(:date,),Tuple{Array{Date,1}}}},NamedTuple{(:left, :right),Tuple{StructArrays.StructArray{NamedTuple{(),Tuple{}},1,NamedTuple{(),Tuple{}}},StructArrays.StructArray{NamedTuple{(:value,),Tuple{Union{Missing, Int64}}},1,NamedTuple{(:value,),Tuple{Array{Union{Missing, Int64},1}}}}}},typeof(IndexedTables.concat_tup),StructArrays.StructArray{NamedTuple{(),Tuple{}},1,NamedTuple{(),Tuple{}}},StructArrays.StructArray{NamedTuple{(:value,),Tuple{Union{Missing, Int64}}},1,NamedTuple{(:value,),Tuple{Array{Int64,1}}}},StructArrays.StructArray{NamedTuple{(:date,),Tuple{Date}},1,NamedTuple{(:date,),Tuple{Array{Date,1}}}},StructArrays.StructArray{NamedTuple{(:date,),Tuple{Date}},1,NamedTuple{(:date,),Tuple{Array{Date,1}}}},Array{Int64,1},Array{Int64,1},Bool,Bool}, ::Base.Iterators.Filter{getfield(IndexedTables, Symbol("##259#268")),StructArrays.GroupJoinPerm{StructArrays.GroupPerm{StructArrays.StructArray{NamedTuple{(:date,),Tuple{Date}},1,NamedTuple{(:date,),Tuple{Array{Date,1}}}},Array{Int64,1},Base.OneTo{Int64}},StructArrays.GroupPerm{StructArrays.StructArray{NamedTuple{(:date,),Tuple{Date}},1,NamedTuple{(:date,),Tuple{Array{Date,1}}}},Array{Int64,1},Base.OneTo{Int64}}}}) at .\abstractarray.jl:1835
 [14] #_join!#256(::Type, ::Nothing, ::Nothing, ::Function, ::StructArrays.StructArray{NamedTuple{(:date,),Tuple{Date}},1,NamedTuple{(:date,),Tuple{Array{Date,1}}}}, ::NamedTuple{(:left, :right),Tuple{StructArrays.StructArray{NamedTuple{(),Tuple{}},1,NamedTuple{(),Tuple{}}},StructArrays.StructArray{NamedTuple{(:value,),Tuple{Union{Missing, Int64}}},1,NamedTuple{(:value,),Tuple{Array{Union{Missing, Int64},1}}}}}}, ::Val{:left}, ::Val{false}, ::typeof(IndexedTables.concat_tup), ::StructArrays.GroupJoinPerm{StructArrays.GroupPerm{StructArrays.StructArray{NamedTuple{(:date,),Tuple{Date}},1,NamedTuple{(:date,),Tuple{Array{Date,1}}}},Array{Int64,1},Base.OneTo{Int64}},StructArrays.GroupPerm{StructArrays.StructArray{NamedTuple{(:date,),Tuple{Date}},1,NamedTuple{(:date,),Tuple{Array{Date,1}}}},Array{Int64,1},Base.OneTo{Int64}}}, ::StructArrays.StructArray{NamedTuple{(),Tuple{}},1,NamedTuple{(),Tuple{}}}, ::StructArrays.StructArray{NamedTuple{(:value,),Tuple{Union{Missing, Int64}}},1,NamedTuple{(:value,),Tuple{Array{Int64,1}}}}) at C:\Users\Max\.julia\packages\IndexedTables\DgX0A\src\join.jl:72
 [15] (::getfield(IndexedTables, Symbol("#kw##_join!")))(::NamedTuple{(:missingtype, :init_group, :accumulate),Tuple{DataType,Nothing,Nothing}}, ::typeof(IndexedTables._join!), ::StructArrays.StructArray{NamedTuple{(:date,),Tuple{Date}},1,NamedTuple{(:date,),Tuple{Array{Date,1}}}}, ::NamedTuple{(:left, :right),Tuple{StructArrays.StructArray{NamedTuple{(),Tuple{}},1,NamedTuple{(),Tuple{}}},StructArrays.StructArray{NamedTuple{(:value,),Tuple{Union{Missing, Int64}}},1,NamedTuple{(:value,),Tuple{Array{Union{Missing, Int64},1}}}}}}, ::Val{:left}, ::Val{false}, ::Function, ::StructArrays.GroupJoinPerm{StructArrays.GroupPerm{StructArrays.StructArray{NamedTuple{(:date,),Tuple{Date}},1,NamedTuple{(:date,),Tuple{Array{Date,1}}}},Array{Int64,1},Base.OneTo{Int64}},StructArrays.GroupPerm{StructArrays.StructArray{NamedTuple{(:date,),Tuple{Date}},1,NamedTuple{(:date,),Tuple{Array{Date,1}}}},Array{Int64,1},Base.OneTo{Int64}}}, ::StructArrays.StructArray{NamedTuple{(),Tuple{}},1,NamedTuple{(),Tuple{}}}, ::StructArrays.StructArray{NamedTuple{(:value,),Tuple{Union{Missing, Int64}}},1,NamedTuple{(:value,),Tuple{Array{Int64,1}}}}) at .\none:0
 [16] #join#276(::Symbol, ::Bool, ::Symbol, ::Symbol, ::Tuple{}, ::Tuple{Int64}, ::Nothing, ::Bool, ::Type, ::Nothing, ::Nothing, ::typeof(join), ::typeof(IndexedTables.concat_tup), ::IndexedTable{StructArrays.StructArray{NamedTuple{(:date,),Tuple{Date}},1,NamedTuple{(:date,),Tuple{Array{Date,1}}}}}, ::IndexedTable{StructArrays.StructArray{NamedTuple{(:date, :value),Tuple{Date,Int64}},1,NamedTuple{(:date, :value),Tuple{Array{Date,1},Array{Int64,1}}}}}) at C:\Users\Max\.julia\packages\IndexedTables\DgX0A\src\join.jl:187
 [17] (::getfield(Base, Symbol("#kw##join")))(::NamedTuple{(:how, :lkey, :rkey),Tuple{Symbol,Symbol,Symbol}}, ::typeof(join), ::Function, ::IndexedTable{StructArrays.StructArray{NamedTuple{(:date,),Tuple{Date}},1,NamedTuple{(:date,),Tuple{Array{Date,1}}}}}, ::IndexedTable{StructArrays.StructArray{NamedTuple{(:date, :value),Tuple{Date,Int64}},1,NamedTuple{(:date, :value),Tuple{Array{Date,1},Array{Int64,1}}}}}) at .\none:0
 [18] #join#277 at C:\Users\Max\.julia\packages\IndexedTables\DgX0A\src\join.jl:197 [inlined]
 [19] (::getfield(Base, Symbol("#kw##join")))(::NamedTuple{(:how, :lkey, :rkey),Tuple{Symbol,Symbol,Symbol}}, ::typeof(join), ::IndexedTable{StructArrays.StructArray{NamedTuple{(:date,),Tuple{Date}},1,NamedTuple{(:date,),Tuple{Array{Date,1}}}}}, ::IndexedTable{StructArrays.StructArray{NamedTuple{(:date, :value),Tuple{Date,Int64}},1,NamedTuple{(:date, :value),Tuple{Array{Date,1},Array{Int64,1}}}}}) at .\none:0
 [20] top-level scope at In[3]:5

But the following is fine:

using JuliaDB, Dates

t1 = table((date = [Date(2008,12,31), Date(2009,12,31), Date(2010,12,31)], height = [4,5,6]))
t2 = table((date = [Date(2008,12,31), Date(2009,12,31)], value = [1,2]))

join(t1, t2, how = :left, lkey = :date, rkey = :date)

[piever]

The issue is that rows(t, cols) , whenever cols is empty, returns that funny object:StructArrays.StructArray{NamedTuple{(),Tuple{}},1,NamedTuple{(),Tuple{}}} with indices 1:0. When join tries to access it, it errors. The problem is that rows(t, cols) can't be a StructArray of the correct length because the length of the StructArray is the length of the columns and without columns this is undefined. Here I think the current solution (creating something with 0 length) is not ideal. I guess we could change rows(t, cols) to return fill(NamedTuple(), length(t)) so that length and eltype are correct, in which case I imagine join should work out of the box.