throw ArgumentError on transitiveclosure!(::MetaGraph) (#90)

* throw ArgumentError on transitiveclosure!(::MetaGraph)

previously, this would not return an error but would not update the underlying graph structure.

Note: simply calling `transitiveclosure!(G.graph)` also fails as this does not update the metadata, e.g. `G.edge_data`.

* add selflooped opt arg

* add test

* Update src/metagraph.jl

Co-authored-by: Guillaume Dalle <[email protected]>

---------

Co-authored-by: Guillaume Dalle <[email protected]>

Author: Daniel Bergman

src/metagraph.jl

@@ -248,3 +248,7 @@ This can be useful to interpret the results of methods inherited from `Graphs`.
 function label_for(meta_graph::MetaGraph, code::Integer)
     return meta_graph.vertex_labels[code]
 end
+
+function Graphs.transitiveclosure!(meta_graph::MetaGraph, selflooped=false)
+    throw(ArgumentError("transitiveclosure! not implemented for type MetaGraph"))
+end

test/misc.jl

@@ -82,3 +82,10 @@ end
     (from, to) = first(edge_labels(graph))
     @test graph[from, to] === 1
 end
+
+@testset "No transitiveclosure! for MetaGraph" begin
+    graph = MetaGraph(
+        complete_graph(2), ["3" => nothing, "2" => nothing], [("3", "2") => 1]
+    )
+    @test_throws ArgumentError transitiveclosure!(graph)
+end