give markershape precedence over marker (#4651)

* give markershape precedence over marker

* Update test/test_args.jl

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

src/args.jl

@@ -1106,7 +1106,7 @@ end
 
 function processMarkerArg(plotattributes::AKW, arg)
     # markershape
-    if allShapes(arg)
+    if allShapes(arg) && !haskey(plotattributes, :markershape)
         plotattributes[:markershape] = arg
 
         # stroke style

test/test_args.jl

@@ -1,3 +1,30 @@
+struct Foo{T}
+    x::Vector{T}
+    y::Vector{T}
+end
+
+@recipe function f(foo::Foo)
+    xlabel --> "x"
+    ylabel --> "y"
+    seriestype --> :path
+    marker --> :auto
+    return foo.x, foo.y
+end
+
+x = collect(0.0:10.0)
+foo = Foo(x, sin.(x))
+
+@testset "Magic attributes" begin
+    @test plot(foo)[1][1][:markershape] === :+
+    @test plot(foo, markershape = :diamond)[1][1][:markershape] === :diamond
+    @test plot(foo, marker = :diamond)[1][1][:markershape] === :diamond
+    @test (@test_logs (:warn, "Skipped marker arg diamond.") plot(
+        foo,
+        marker = :diamond,
+        markershape = :diamond,
+    )[1][1][:markershape]) === :diamond
+end
+
 @testset "Subplot Attributes" begin
     let pl = plot(rand(4, 4), layout = 2)
         @test pl[1].primary_series_count == 2