Merging of Themes / Attributes with duplicated entries ignores rightmost value

[haakon-e]

Merging of Themes / Attributes with duplicated entries does not work how Base.merge does.

julia> theme1 = Theme(fontsize=8)
Attributes with 1 entry:
  fontsize => 8

julia> theme2 = Theme(fontsize=800)
Attributes with 1 entry:
  fontsize => 800

julia> merge(theme1, theme2)
Attributes with 1 entry:
  fontsize => 8

I would expect the result of the merge to be:

julia> merge(theme1, theme2)
Attributes with 1 entry:
  Axis => Attributes with 1 entry:
    titlesize => 100

which is the effect of e.g. set_theme!, update_theme!, with_theme.

Makie.merge does not have its own docstring explaining this, so if you do ?merge or ?Makie.merge you'll be shown explanations for other types, all of which tell you variants of the docs for Base.merge (my emphasis):

merge(d::AbstractDict, others::AbstractDict...)

Construct a merged collection from the given collections. If necessary, the types of the resulting collection will be promoted to accommodate the types of the merged collections. If the same key is present in another collection, the value for that key will be the value it has in the last collection listed.

Relevant LOC:

Makie.jl/MakieCore/src/attributes.jl

Lines 248 to 263 in 44d00b4

	function merge_attributes!(input::Attributes, theme::Attributes)
	for (key, value) in attributes(theme)
	if !haskey(input, key)
	input[key] = value
	else
	current_value = input[key]
	tvalue = to_value(value)
	if tvalue isa Attributes && current_value isa Attributes
	# if nested attribute, we merge recursively
	merge_attributes!(current_value, tvalue)
	end
	# we're good! input already has a value, can ignore theme
	end
	end
	return input
	end

---

• what version of Makie are you running? (]st -m Makie) v0.21.11
• can you reproduce the bug with a fresh environment ? (]activate --temp; add Makie)
• What platform + GPU are you on? Mac M1