fix == on incomplete Composites

Author: oxinabox

src/differentials/composite.jl

@@ -45,7 +45,15 @@ function Composite{P}(d::Dict) where {P<:Dict}
     return Composite{P, typeof(d)}(d)
 end
 
-Base.:(==)(a::Composite, b::Composite) = backing(a) == backing(b)
+function Base.:(==)(a::Composite{P, T}, b::Composite{P, T}) where {P, T}
+    return backing(a) == backing(b)
+end
+function Base.:(==)(a::Composite{P}, b::Composite{P}) where {P, T}
+    return canonicalize(a) == canonicalize(b)
+end
+Base.:(==)(a::Composite{P}, b::Composite{Q}) where {P, Q} = false
+
+Base.hash(a::Composite, h::UInt) = Base.hash(backing(canonicalize(a)), h)
 
 function Base.show(io::IO, comp::Composite{P}) where P
     print(io, "Composite{")
@@ -155,6 +163,9 @@ end
 # Tuple composites are always in their canonical form
 canonicalize(comp::Composite{<:Tuple, <:Tuple}) = comp
 
+# Dict composite are always in their canonical form.
+canonicalize(comp::Composite{<:Any, <:AbstractDict}) = comp
+
 """
     _zeroed_backing(P)
 
@@ -206,7 +217,7 @@ function elementwise_add(a::NamedTuple{an}, b::NamedTuple{bn}) where {an, bn}
     # https://github.com/JuliaLang/julia/blob/592748adb25301a45bd6edef3ac0a93eed069852/base/namedtuple.jl#L220-L231
     if @generated
         names = Base.merge_names(an, bn)
-        
+
         vals = map(names) do field
             a_field = :(getproperty(a, $(QuoteNode(field))))
             b_field = :(getproperty(b, $(QuoteNode(field))))

test/differentials/composite.jl

@@ -29,6 +29,22 @@ end
         @test convert(Dict, Composite{Dict}(Dict(4 => 3))) == Dict(4 => 3)
     end
 
+    @testset "==" begin
+        @test Composite{Foo}(x=0.1, y=2.5) == Composite{Foo}(x=0.1, y=2.5)
+        @test Composite{Foo}(x=0.1, y=2.5) == Composite{Foo}(y=2.5, x=0.1)
+        @test Composite{Foo}(y=2.5, x=Zero()) == Composite{Foo}(y=2.5)
+
+        @test Composite{Tuple{Float64,}}(2.0) == Composite{Tuple{Float64,}}(2.0)
+        @test Composite{Dict}(Dict(4 => 3) == Composite{Dict}(Dict(4 => 3)
+
+    end
+
+    @testset "hash" begin
+        @test hash(Composite{Foo}(x=0.1, y=2.5)) == hash(Composite{Foo}(y=2.5, x=0.1))
+        @test hash(Composite{Foo}(y=2.5, x=Zero())) == hash(Composite{Foo}(y=2.5))
+    end
+
+
     @testset "indexing, iterating, and properties" begin
         @test keys(Composite{Foo}(x=2.5)) == (:x,)
         @test propertynames(Composite{Foo}(x=2.5)) == (:x,)
@@ -78,7 +94,15 @@ end
 
     @testset "canonicalize" begin
         # Testing iterate via collect
-        @test collect(Composite{Tuple{Float64,}}(2.0)) == [2.0]
+        @test ==(
+            canonicalize(Composite{Tuple{Float64,}}(2.0))
+            Composite{Tuple{Float64,}}(2.0)
+        )
+
+        @test ==(
+            canonicalize(Composite{Dict}(Dict(4 => 3))))
+            Composite{Dict}(Dict(4 => 3)))
+        )
 
         # For structure it needs to match order and Zero() fill to match primal
         CFoo = Composite{Foo}
@@ -219,7 +243,7 @@ end
 
     @testset "show" begin
         @test repr(Composite{Foo}(x=1,)) == "Composite{Foo}(x = 1,)"
-        # check for exact regex match not occurence( `^...$`) 
+        # check for exact regex match not occurence( `^...$`)
         # and allowing optional whitespace (`\s?`)
         @test occursin(
             r"^Composite{Tuple{Int64,\s?Int64}}\(1,\s?2\)$",