fix for multiple identical names

src/named_systems2.jl

@@ -372,7 +372,7 @@ function ControlSystemsBase.feedback(s1::NamedStateSpace{T}, s2::NamedStateSpace
             B = B[:, kept_inds]
             D = D[:, kept_inds]
             deleteat!(s1u, inds[2:end])
-            s1 = named_ss(ControlSystemsBase.basetype(s1.sys)(s1.A, B, s1.C, D, s1.timeevol), x=s1.x, u=s1u, y=s1.y, name=s1.name)
+            s1 = named_ss(ControlSystemsBase.basetype(s1.sys)(s1.A, B, s1.C, D, s1.timeevol); x=s1.x, u=s1u, y=s1.y, name=s1.name, unique)
         end
     end
 

test/test_named_systems2.jl

@@ -324,3 +324,59 @@ sys_connect2 = connect([sys_1, sys_2, split], [:out_z => :in_z, :in_y1=>:in_y1,
 # Make gensym state names equal to assist equality testing below
 sys_connect2.x .= sys_connect.x
 @test sys_connect == sys_connect2
+
+# Discrete
+s1 = ssrand(1,2,2, Ts=1)
+s2 = ssrand(1,2,2, Ts=1)
+sys_1=named_ss(s1, u=[:in_x, :in_y], y=:out_z, x=[:x1, :x2])
+sys_2=named_ss(s2, u=[:in_y, :in_z], y=:out, x = [:x3, :x4])
+
+@test_throws "u names not unique. Repeated names: [:in_y] To allow connecting a single input signal to several inputs with the same name, pass `unique = false`." connect([sys_1, sys_2], [:out_z => :in_z]; w1 = [:in_x, :in_y], z1 = :out)
+sys_connect = connect(
+    [sys_1, sys_2],
+    [:out_z => :in_z];
+    w1 = [:in_x, :in_y],
+    z1 = :out,
+    unique=false
+)
+
+sys_1=named_ss(s1, u=[:in_x, :in_y1], y=:out_z, x=[:x1, :x2])
+sys_2=named_ss(s2, u=[:in_y2, :in_z], y=:out, x = [:x3, :x4])
+split = splitter(:in_y, 2, sys_1.timeevol)
+sys_connect2 = connect([sys_1, sys_2, split], [:out_z => :in_z, :in_y1=>:in_y1, :in_y2=>:in_y2]; w1 = [:in_x, :in_y], z1 = :out)
+
+# Make gensym state names equal to assist equality testing below
+sys_connect2.x .= sys_connect.x
+@test sys_connect == sys_connect2
+
+
+## Multiple identical names
+s1 = ssrand(1,3,2)
+s2 = ssrand(1,3,2)
+s3 = ssrand(1,1,1)
+
+sys_1 = named_ss(s1, u=[:in_a, :in_b, :in_c], y=[:ui_ref], x=[:x1, :x2])
+sys_2 = named_ss(s2, u=[:in_e, :in_c, :in_d], y=:out_a, x=[:x3, :x4]);
+sys_3 = named_ss(s3, u=:in_d, y=:out_e, x=:x5);
+sys_connect = connect([sys_1, sys_2, sys_3],
+    [:out_a => :in_a];
+    w1 = [:in_b, :in_c, :in_d],
+    z1 = :ui_ref,
+    unique = false
+)
+
+
+split1 = splitter(:in_c, 2, sys_1.timeevol)
+split2 = splitter(:in_d, 2, sys_1.timeevol)
+
+sys_1 = named_ss(s1, u=[:in_a, :in_b, :in_c1], y=[:ui_ref], x=[:x1, :x2])
+sys_2 = named_ss(s2, u=[:in_e, :in_c2, :in_d1], y=:out_a, x=[:x3, :x4]);
+sys_3 = named_ss(s3, u=:in_d2, y=:out_e, x=:x5);
+sys_connect2 = connect([sys_1, sys_2, sys_3, split1, split2],
+    [:out_a => :in_a, :in_c1=>:in_c1, :in_c2=>:in_c2, :in_d1=>:in_d1, :in_d2=>:in_d2];
+    w1 = [:in_b, :in_c, :in_d],
+    z1 = :ui_ref,
+    unique = false
+)
+sys_connect2.x .= sys_connect.x
+@test sys_connect == sys_connect2