FlowBoundary is flow direction constraining

(cherry picked from commit e84ae3a)

core/src/allocation_init.jl

@@ -7,7 +7,8 @@ function find_subnetwork_connections!(p::Parameters)::Nothing
     # destination node subnetwork id ≠1
     for node_id in graph[].node_ids[1]
         for outflow_id in outflow_ids(graph, node_id)
-            if graph[outflow_id].subnetwork_id != 1
+            if (graph[outflow_id].subnetwork_id != 1) ||
+               (graph[node_id, outflow_id].subnetwork_id_source == 1)
                 main_network_source_edges =
                     get_main_network_connections(p, graph[outflow_id].subnetwork_id)
                 edge = (node_id, outflow_id)

core/src/allocation_optim.jl

@@ -865,7 +865,9 @@ function save_allocation_flows!(
         end
 
         # Check whether the next edge is the current one reversed
-        if edge_2 == reverse(edge_1)
+        # and the edge does not have a UserDemand end
+        if edge_2 == reverse(edge_1) &&
+           !(edge_1[1].type == NodeType.UserDemand || edge_1[2].type == NodeType.UserDemand)
             # If so, these edges are both processed in this iteration
             flow_rate += sign_2 * JuMP.value(F[edge_2])
             skip = true

core/src/util.jl

@@ -572,8 +572,15 @@ is_flow_constraining(node::AbstractParameterNode) = hasfield(typeof(node), :max_
 
 """Whether the given node is flow direction constraining (only in direction of edges)."""
 is_flow_direction_constraining(node::AbstractParameterNode) = (
-    node isa
-    Union{Pump, Outlet, TabulatedRatingCurve, FractionalFlow, Terminal, UserDemand}
+    node isa Union{
+        Pump,
+        Outlet,
+        TabulatedRatingCurve,
+        FractionalFlow,
+        Terminal,
+        UserDemand,
+        FlowBoundary,
+    }
 )
 
 function has_main_network(allocation::Allocation)::Bool