Fix undirected edges (#88)

Author: gdalle

Diff for: Project.toml

@@ -1,6 +1,6 @@
 name = "MetaGraphsNext"
 uuid = "fa8bd995-216d-47f1-8a91-f3b68fbeb377"
-version = "0.7.1"
+version = "0.7.2"
 
 [deps]
 Graphs = "86223c79-3864-5bf0-83f7-82e725a168b6"

Diff for: src/directedness.jl

@@ -17,11 +17,15 @@ to be robust to vertex re-coding, so the labels need to support `<`.
 """
 function arrange end
 
-@traitfn function arrange(::MG, label_1, label_2) where {MG <: MetaGraph; IsDirected{MG}}
+@traitfn function arrange(
+    ::MG, label_1, label_2
+) where {MG <: AbstractGraph; IsDirected{MG}}
     return label_1, label_2
 end
 
-@traitfn function arrange(::MG, label_1, label_2) where {MG <: MetaGraph; !IsDirected{MG}}
+@traitfn function arrange(
+    ::MG, label_1, label_2
+) where {MG <: AbstractGraph; !IsDirected{MG}}
     if label_1 < label_2
         (label_1, label_2)
     else

Diff for: src/graphs.jl

@@ -315,7 +315,9 @@ end
     edge_data = meta_graph.edge_data
     reverse_edge_data = empty(edge_data)
     for (label_1, label_2) in keys(edge_data)
-        reverse_edge_data[(label_2, label_1)] = edge_data[(label_1, label_2)]
+        reverse_edge_data[arrange(meta_graph, label_2, label_1)] = edge_data[arrange(
+            meta_graph, label_1, label_2
+        )]
     end
     return MetaGraph(
         reverse(meta_graph.graph),

Diff for: src/metagraph.jl

@@ -185,7 +185,7 @@ function MetaGraph(
     end
     edge_data = Dict{Tuple{Label,Label},EdgeData}()
     for ((label_1, label_2), data) in edges_description
-        edge_data[label_1, label_2] = data
+        edge_data[arrange(graph, label_1, label_2)] = data
     end
     return MetaGraph(
         graph,

Diff for: test/misc.jl

@@ -72,3 +72,13 @@ end
     # compare
     @test mg == mg2
 end
+
+@testset "Undirected edges" begin
+    graph = MetaGraph(
+        complete_graph(2), ["3" => nothing, "2" => nothing], [("3", "2") => 1]
+    )
+    @test haskey(graph, "2", "3")
+    @test haskey(graph, "3", "2")
+    (from, to) = first(edge_labels(graph))
+    @test graph[from, to] === 1
+end