conversion traits not taken into account in 0.21

[aplavin]

In 0.21, convert_argument(trait, args...) methods are not really called with user-specified arguments.
That's due to the new expand_dimensions function called before convert_arguments with conversion trait:

Makie.jl/src/conversions.jl

Lines 17 to 21 in d157f9c

	CT = conversion_trait(T, args...)
	# Try to expand dimensions first, as this is the most basic step!
	expanded = expand_dimensions(CT, args...)
	!isnothing(expanded) && return convert_arguments(T, expanded...; kw...)

.

Noticed when trying to update KeyedArray conversions (in AxisKeysExtra.jl) to the new Makie version, specifically conversions like https://github.com/JuliaAPlavin/AxisKeysExtra.jl/blob/0000000065d69673f7f40c0f93f01ba0fbbbda34/ext/MakieExt.jl#L10-L13. MWE:

julia> using AxisKeys, Makie

julia> Makie.convert_arguments(ct::PointBased, x::KeyedArray{<:Any,1}) = convert_arguments(ct, only(axiskeys(x)), AxisKeys.keyless_unname(x))

julia> convert_arguments(Scatter, KeyedArray([1,2,3], x=10:10:30))
# 0.20, expected:
(Point{2, Float32}[[10.0, 1.0], [20.0, 2.0], [30.0, 3.0]],)
# 0.21, unexpected:
(10:10:30, Point{2, Float64}[[1.0, 1.0], [2.0, 2.0], [3.0, 3.0]])

• are you running newest version (version from docs) ? bug only appears in 0.21, while 0.20 works fine
• can you reproduce the bug with a fresh environment ? (]activate --temp; add Makie)
• What platform + GPU are you on? any platform

[aplavin]

Hmm, trying the most recent release – the underlying issue doesn't seem really fixed by that PR of mine...
Can we reopen this?

Example from the first post works, but actual plotting doesn't.

julia> using AxisKeys, Makie

julia> Makie.convert_arguments(ct::PointBased, x::KeyedArray{<:Any,1}) = convert_arguments(ct, only(axiskeys(x)), AxisKeys.keyless_unname(x))

julia> scatter(KeyedArray([1,2,3], x=10:10:30))
# Makie 0.20: shows the plot
# Makie 0.21.2: throws
ERROR: ArgumentError:     Conversion failed for Scatter (With conversion trait PointBased()) with args: Tuple{StepRange{Int64, Int64}, Vector{Point{2, Float64}}} .
    Scatter requires to convert to argument types Tuple{AbstractVector{<:Union{Point2, Point3}}}, which convert_arguments didn't succeed in.
    To fix this overload convert_arguments(P, args...) for Scatter or PointBased() and return an object of type Tuple{AbstractVector{<:Union{Point2, Point3}}}.`

Stacktrace:
 [1] conversion_pipeline(P::Type{…}, used_attrs::Tuple{}, args::Tuple{…}, args_obs::Tuple{…}, user_attributes::Dict{…}, deregister::Vector{…}, recursion::Int64)
   @ Makie ~/.julia/packages/Makie/We6MY/src/interfaces.jl:240
 [2] conversion_pipeline(P::Type{…}, used_attrs::Tuple{}, args::Tuple{…}, args_obs::Tuple{…}, user_attributes::Dict{…}, deregister::Vector{…}, recursion::Int64)
   @ Makie ~/.julia/packages/Makie/We6MY/src/interfaces.jl:233
 [3] conversion_pipeline(P::Type{…}, used_attrs::Tuple{}, args::Tuple{…}, args_obs::Tuple{…}, user_attributes::Dict{…}, deregister::Vector{…})
   @ Makie ~/.julia/packages/Makie/We6MY/src/interfaces.jl:213
 [4] (Scatter)(user_args::Tuple{KeyedArray{Int64, 1, NamedDimsArray{…}, Base.RefValue{…}}}, user_attributes::Dict{Symbol, Any})
   @ Makie ~/.julia/packages/Makie/We6MY/src/interfaces.jl:271
 [5] _create_plot(F::Function, attributes::Dict{Symbol, Any}, args::KeyedArray{Int64, 1, NamedDimsArray{…}, Base.RefValue{…}})
   @ Makie ~/.julia/packages/Makie/We6MY/src/figureplotting.jl:316
 [6] #scatter#72
   @ ~/.julia/packages/MakieCore/8S3xT/src/recipes.jl:436 [inlined]
 [7] scatter(args::KeyedArray{Int64, 1, NamedDimsArray{(:x,), Int64, 1, Vector{Int64}}, Base.RefValue{StepRange{Int64, Int64}}})
   @ MakieCore ~/.julia/packages/MakieCore/8S3xT/src/recipes.jl:434
 [8] top-level scope
   @ REPL[3]:1
Some type information was truncated. Use `show(err)` to see complete types.

Any ideas on how to actually fix it? conversion_pipeline looks quite involved...

[aplavin]

This time I don't even see a way to work around this issue... Any advice welcome!
Hope Makie intends to continue supporting convert_arguments stuff.

[asinghvi17]

Defining Makie.expand_dimensions(::PointBased, k::KeyedArray) = (only(axiskeys(x)), AxisKeys.keyless_unname(x)) seems to fix it, though I imagine that's not the ideal way forward.

My guess is that KeyedArrays are hitting [7] expand_dimensions(::PointBased, y::AbstractVector{T} where T<:Real) @ ~/.julia/dev/Makie/src/interfaces.jl:136, since they are AbstractArrays...

[aplavin]

Thanks for the suggestion, will try that!
It's kinda confusing, I thought convert_arguments should be applied first by design. Its goal is basically "convert user type to what we understand", while expand_dimensions seems to be "convert one type we understand to another".

[SimonDanisch]

It's a separate step to divide a user defined type into it's x and y components