resolve CairoMakie insert! ambiguity

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## [Unreleased]
 
 - Correct a bug in the `project` function when projecting using a `Scene`. [#3909](https://github.com/MakieOrg/Makie.jl/pull/3909).
+- Correct a method ambiguity in `insert!` which was causing `PlotList` to fail on CairoMakie. [#4038](https://github.com/MakieOrg/Makie.jl/pull/4038)
 
 ## [0.21.5] - 2024-07-07
 

CairoMakie/src/screen.jl

@@ -204,6 +204,8 @@ Base.size(screen::Screen) = round.(Int, (screen.surface.width, screen.surface.he
 # we render the scene directly, since we have
 # no screen dependent state like in e.g. opengl
 Base.insert!(screen::Screen, scene::Scene, plot) = nothing
+# to resolve method ambiguity, since this method is defined in Makie for MakieScreen and PlotList:
+Base.insert!(screen::Screen, scene::Scene, plot::Plot{plotlist}) = nothing
 function Base.delete!(screen::Screen, scene::Scene, plot::AbstractPlot)
     # Currently, we rerender every time, so nothing needs
     # to happen here.  However, in the event that changes,

CairoMakie/test/runtests.jl

@@ -134,6 +134,12 @@ end
     rm("test.mp4")
 end
 
+@testset "plotlist no ambiguity (#4038)" begin
+    f = plotlist([Makie.SpecApi.Scatter(1:10)])
+    Makie.colorbuffer(f; backend=CairoMakie)
+    plotlist!([Makie.SpecApi.Scatter(1:10)])
+end
+
 
 excludes = Set([
     "Colored Mesh",