Better error messages

Author: mschauer

src/dsep.jl

@@ -21,9 +21,6 @@ function dsep(g::AbstractGraph, U, V, S; verbose = false)
         blocked[ve] = true
     end
 
-    #(in_seen[u] || in_seen[v]) && throw(ArgumentError("S should not contain u or v"))
-    #intersect(u, v) && throw(ArgumentError("u ∩ v ≠ ∅"))
-
     next = Vector{T}()
 
     # mark vertices with descendants in S
@@ -49,23 +46,22 @@ function dsep(g::AbstractGraph, U, V, S; verbose = false)
 
     for u in U
         push!(in_next, u) # treat u as vertex reached backwards
+        in_seen[u] && throw(ArgumentError("U and S not disjoint."))
         in_seen[u] = true
     end
     if V isa Integer
+        in_seen[V] && throw(ArgumentError("U, V and S not disjoint."))
         return dsep_inner!(g, in_next, out_next, descendant, ==(V), blocked, out_seen, in_seen; verbose)
     else
         isv = falses(nv(g))
         for v in V
+            in_seen[v] && throw(ArgumentError("U, V and S not disjoint."))
             isv[v] = true
         end
         return dsep_inner!(g, in_next, out_next, descendant, w->isv[w], blocked, out_seen, in_seen; verbose)
     end
 end
 
-#=
-Sketch of the algorithm:
-
-=#
 function dsep_inner!(g, in_next, out_next, descendant, found, blocked, out_seen, in_seen; verbose=false)
     while true
         sin = isempty(in_next)

test/gensearch.jl

@@ -90,4 +90,7 @@ end
 @testset "dsep vs alt_test_dsep" begin
     test_dsep(g1)
     test_dsep(g2)
+    @test_throws ArgumentError dsep(g1, [1,2], [2,3], [4,5])
+    @test_throws ArgumentError dsep(g1, [1,2], [3,4], [4,5])
+    @test_throws ArgumentError dsep(g1, [1,2], [3,4], [5,1])
 end