Can't plot a second Lines SpecApi.PlotSpec with Date x-axis

[rdboyes]

• what version of Makie are you running? (]st -m Makie)

(jl_OOZ0Ex) pkg> status
Status `/tmp/jl_OOZ0Ex/Project.toml`
  [ee78f7c6] Makie v0.22.1
  [ade2ca70] Dates v1.11.0

• can you reproduce the bug with a fresh environment ? (]activate --temp; add Makie)

yes

• What platform + GPU are you on?

Ubuntu 24.04, Nvidia 1080

Using the SpecApi, you get the error ArgumentError: Cannot change dim conversion for dimension 1, since it already is set to a conversion: Makie.DateTimeConversion(Observable(Date)). when trying to plot a second Lines object if the x axis is a Date. This operation works fine if the x axis is not a Date or if you don't use the SpecApi.

using Dates
using Makie

xdates = Date.(["2025-02-17", "2025-02-18"])
nums1 = [1, 2]
nums2 = [3, 4]

Makie.plot(
        Makie.SpecApi.GridLayout(
            Makie.SpecApi.Axis(
                plots=[
                    Makie.PlotSpec(
                        :Lines,
                        xdates,
                        nums1),
                    Makie.PlotSpec(
                        :Lines,
                        xdates,
                        nums2)
                ]
            )
        )
    )

Expected output:

f, _, pl = lines(xdates, nums1)
lines!(f[1,1], xdates, nums2)
f

Full stacktrace:

ERROR: ArgumentError: Cannot change dim conversion for dimension 1, since it already is set to a conversion: Makie.DateTimeConversion(Observable(Date)).
Stacktrace:
  [1] setindex!(conversions::Makie.DimConversions, value::Makie.DateTimeConversion, i::Int64)
    @ Makie ~/.julia/packages/Makie/Q6F2P/src/dim-converts/dim-converts.jl:35
  [2] (::Makie.var"#201#202"{Makie.DimConversions, Int64})(val::Makie.DateTimeConversion)
    @ Makie ~/.julia/packages/Makie/Q6F2P/src/dim-converts/dim-converts.jl:23
  [3] on(f::Any, observable::Observables.AbstractObservable; weak::Bool, priority::Int64, update::Bool)
    @ Observables ~/.julia/packages/Observables/YdEbO/src/Observables.jl:368
  [4] on
    @ ~/.julia/packages/Observables/YdEbO/src/Observables.jl:361 [inlined]
  [5] setindex!
    @ ~/.julia/packages/Makie/Q6F2P/src/dim-converts/dim-converts.jl:22 [inlined]
  [6] connect_conversions!(conversions::Makie.DimConversions, new_conversions::Makie.DimConversions)
    @ Makie ~/.julia/packages/Makie/Q6F2P/src/dim-converts/dim-converts.jl:139
  [7] connect_plot!(parent::Scene, plot::Lines{Tuple{Vector{Point{2, Float64}}}})
    @ Makie ~/.julia/packages/Makie/Q6F2P/src/interfaces.jl:394
  [8] diff_plotlist!(scene::Scene, plotspecs::Vector{PlotSpec}, obs_to_notify::Vector{Observable}, plotlist::Nothing, reusable_plots::IdDict{PlotSpec, Plot}, new_plots::IdDict{PlotSpec, Plot})
    @ Makie ~/.julia/packages/Makie/Q6F2P/src/specapi.jl:611
  [9] (::Makie.var"#update_plotlist#1132"{Scene, Nothing, IdDict{PlotSpec, Plot}, IdDict{PlotSpec, Plot}, Bool, Vector{Observable}})(plotspecs::Vector{PlotSpec})
    @ Makie ~/.julia/packages/Makie/Q6F2P/src/specapi.jl:651
 [10] (::Makie.var"#1131#1136"{Vector{PlotSpec}})()
    @ Makie ~/.julia/packages/Makie/Q6F2P/src/specapi.jl:675
 [11] lock(f::Makie.var"#1131#1136"{Vector{PlotSpec}}, l::ReentrantLock)
    @ Base ./lock.jl:232
 [12] (::Makie.var"#1130#1135"{ReentrantLock})(plotspecs::Vector{PlotSpec})
    @ Makie ~/.julia/packages/Makie/Q6F2P/src/specapi.jl:674
 [13] on(f::Any, observable::Observables.AbstractObservable; weak::Bool, priority::Int64, update::Bool)
    @ Observables ~/.julia/packages/Observables/YdEbO/src/Observables.jl:368
 [14] on
    @ ~/.julia/packages/Observables/YdEbO/src/Observables.jl:361 [inlined]
 [15] #on#238
    @ ~/.julia/packages/Makie/Q6F2P/src/scenes.jl:152 [inlined]
 [16] on
    @ ~/.julia/packages/Makie/Q6F2P/src/scenes.jl:151 [inlined]
 [17] update_plotspecs!
    @ ~/.julia/packages/Makie/Q6F2P/src/specapi.jl:673 [inlined]
 [18] update_plotspecs!(scene::Scene, list_of_plotspecs::Observable{Vector{PlotSpec}}, plotlist::Nothing)
    @ Makie ~/.julia/packages/Makie/Q6F2P/src/specapi.jl:642
 [19] update_plotspecs!
    @ ~/.julia/packages/Makie/Q6F2P/src/specapi.jl:642 [inlined]
 [20] update_gridlayout!(gridlayout::GridLayout, nesting::Int64, oldgridspec::Nothing, gridspec::Makie.GridLayoutSpec, previous_contents::Vector{Pair{Tuple{…}, Tuple{…}}}, new_layoutables::Vector{Pair{Tuple{…}, Tuple{…}}})
    @ Makie ~/.julia/packages/Makie/Q6F2P/src/specapi.jl:930
 [21] update_gridlayout!(target_layout::GridLayout, layout_spec::Makie.GridLayoutSpec, unused_layoutables::Vector{Pair{Tuple{…}, Tuple{…}}}, new_layoutables::Vector{Pair{Tuple{…}, Tuple{…}}})
    @ Makie ~/.julia/packages/Makie/Q6F2P/src/specapi.jl:982
 [22] #1150
    @ ~/.julia/packages/Makie/Q6F2P/src/specapi.jl:1033 [inlined]
 [23] lock(f::Makie.var"#1150#1152"{Makie.GridLayoutSpec, GridLayout, Vector{Pair{Tuple{…}, Tuple{…}}}, Vector{Pair{Tuple{…}, Tuple{…}}}}, l::ReentrantLock)
    @ Base ./lock.jl:232
 [24] (::Makie.var"#1149#1151"{GridLayout, ReentrantLock, Vector{Pair{Tuple{…}, Tuple{…}}}, Vector{Pair{Tuple{…}, Tuple{…}}}})(layout_spec::Makie.GridLayoutSpec)
    @ Makie ~/.julia/packages/Makie/Q6F2P/src/specapi.jl:1032
 [25] on(f::Any, observable::Observables.AbstractObservable; weak::Bool, priority::Int64, update::Bool)
    @ Observables ~/.julia/packages/Observables/YdEbO/src/Observables.jl:368
 [26] on
    @ ~/.julia/packages/Observables/YdEbO/src/Observables.jl:361 [inlined]
 [27] #on#238
    @ ~/.julia/packages/Makie/Q6F2P/src/scenes.jl:152 [inlined]
 [28] on
    @ ~/.julia/packages/Makie/Q6F2P/src/scenes.jl:151 [inlined]
 [29] update_fig!(fig::Figure, layout_obs::Observable{Makie.GridLayoutSpec})
    @ Makie ~/.julia/packages/Makie/Q6F2P/src/specapi.jl:1031
 [30] plot!(fig::Figure, plot::Plot{plot, Tuple{Makie.GridLayoutSpec}})
    @ Makie ~/.julia/packages/Makie/Q6F2P/src/specapi.jl:1047
 [31] _create_plot(F::Function, attributes::Dict{Symbol, Any}, args::Makie.GridLayoutSpec)
    @ Makie ~/.julia/packages/Makie/Q6F2P/src/figureplotting.jl:318
 [32] plot(args::Makie.GridLayoutSpec)
    @ MakieCore ~/.julia/packages/MakieCore/sHgwT/src/recipes.jl:58
 [33] top-level scope
    @ REPL[57]:1
Some type information was truncated. Use `show(err)` to see complete types.

[rdboyes]

This can be fixed by editing

Makie.jl/src/dim-converts/dim-converts.jl

Line 29 in e6c3e37

conversions[i] === value && return # ignore same conversion

to

conversions[i] == value && return

and adding

Base.:(==)(a::DateTimeConversion, b::DateTimeConversion) = a.type[] == b.type[]

But this seems like a change with too many consequences to just make a PR

[rdboyes]

Since I have a working fix that seems to pass all tests, I have submitted a PR