fixes nested systems for more than two levels

Author: ValentinKaisermayer

src/systems/optimization/optimizationsystem.jl

@@ -143,13 +143,18 @@ function generate_function(sys::OptimizationSystem, vs = states(sys), ps = param
                           conv = AbstractSysToExpr(sys), kwargs...)
 end
 
+function namespace_objective(sys::AbstractSystem)
+    op = objective(sys)
+    namespace_expr(op, sys)
+end
+
 function objective(sys)
     op = get_op(sys)
     systems = get_systems(sys)
     if isempty(systems)
         op
     else
-        op + reduce(+, map(sys_ -> namespace_expr(get_op(sys_), sys_), systems))
+        op + reduce(+, map(sys_ -> namespace_objective(sys_), systems))
     end
 end
 
@@ -166,7 +171,9 @@ function namespace_inequality(ineq::Inequality, sys, n = nameof(sys))
 end
 
 function namespace_constraints(sys)
-    namespace_constraint.(get_constraints(sys), Ref(sys))
+    cstrs = constraints(sys)
+    isempty(cstrs) && return Vector{Union{Equation, Inequality}}(undef,0)
+    map(cstr -> namespace_constraint(cstr, sys), cstrs)
 end
 
 function constraints(sys)

test/optimizationsystem.jl

@@ -165,6 +165,16 @@ end
     @test isequal(prob_.p, [2.0])
 end
 
+@testset "nested systems" begin
+    @variables x1 x2 x3 x4
+    @named sys1 = OptimizationSystem(x1, [x1], [])
+    @named sys2 = OptimizationSystem(x2, [x2], [], systems=[sys1])
+    @named sys3 = OptimizationSystem(x3, [x3], [], systems=[sys2])
+    @named sys4 = OptimizationSystem(x4, [x4], [], systems=[sys3])
+
+    @test isequal(equations(sys4), sys3.sys2.sys1.x1 + sys3.sys2.x2 + sys3.x3 + x4)
+end
+
 @testset "time dependent var" begin
     @parameters t
     @variables x(t) y