Merge pull request #936 from slwu89/coerce-component-error

Informative error for `coerce_component` with scalar input
AlgebraicJulia · Sep 4, 2024 · 982ea6e · 982ea6e
2 parents b71a5b8 + ce50fb6
commit 982ea6e
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diff --git a/src/categorical_algebra/CSets.jl b/src/categorical_algebra/CSets.jl
@@ -462,7 +462,11 @@ function coerce_component(ob::Symbol, f::FinFunction{Int,Int},
   return f 
 end
 
-coerce_component(::Symbol, f, dom_size::Int, codom_size::Int; kw...) =
+coerce_component(ob::Symbol, f::T, dom_size::Int, codom_size::Int; kw...) where {T<:Integer} =
+  error("Scalar component for $ob not allowed; " *
+  "this is probably from a scalar component in an ACSetTransformation, please use a vector")
+
+coerce_component(::Symbol, f::T, dom_size::Int, codom_size::Int; kw...) where {T<:AbstractVector{<:Integer}}=
   FinFunction(f, dom_size, codom_size; kw...)
 
 function coerce_attrvar_component(

diff --git a/test/categorical_algebra/CSets.jl b/test/categorical_algebra/CSets.jl
@@ -64,6 +64,7 @@ f = ACSetTransformation(X,X; V=[1,2], E=[1,2,3])
 @test components(f) == (V=FinFunction([1,2]), E=FinFunction([1,2,3]), 
                         Weight=VarFunction{Float64}([], FinSet(0)))
 
+@test_throws ErrorException ACSetTransformation(Y,X; V=[1,2], E=1)
 g = ACSetTransformation(Y,X; V=[1,2], E=[1])
 @test is_natural(g)
 @test compose(g,f) |> force == g
@@ -300,6 +301,7 @@ diagram = FreeDiagram([g, ob(terminal(Graph)), Graph(1)], [(α,3,1), (β,3,2)])
 # Constructors and accessors. Test type conversion as well Int -> Float64
 g = path_graph(WeightedGraph{Float64}, 2, E=(weight=2,))
 h = path_graph(WeightedGraph{Float64}, 4, E=(weight=[1,2,3],))
+@test_throws ErrorException ACSetTransformation((V=[2,3], E=2), g, h)
 α = ACSetTransformation((V=[2,3], E=[2]), g, h)
 @test length(components(α)) == 3