From bd01378d92663f45772e6bb7cd9dc4a086a533a5 Mon Sep 17 00:00:00 2001
From: Katherine Mantel <kmantel@users.noreply.github.com>
Date: Thu, 7 Jul 2022 17:16:11 -0400
Subject: [PATCH] Composition: add_projection: also detect feedback from node
 roles (#2429)

Node roles may be specified in various places, including when specifying
a Pathway. These roles can imply that some projections should be
feedback, and it can be cumbersome to check for these in any place
add_projection may be called to pass feedback=True.

This checks for these roles in Composition.add_projection when adding an
edge to the Graph.

Fixes #2004
---
 psyneulink/core/compositions/composition.py |  9 +++++++++
 tests/composition/test_composition.py       | 14 ++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/psyneulink/core/compositions/composition.py b/psyneulink/core/compositions/composition.py
index 40a25c27ab1..b720ef3921e 100644
--- a/psyneulink/core/compositions/composition.py
+++ b/psyneulink/core/compositions/composition.py
@@ -5816,6 +5816,15 @@ def add_projection(self,
             projection.is_processing = False
             # KDM 5/24/19: removing below rename because it results in several existing_projections
             # projection.name = f'{sender} to {receiver}'
+
+            # check for required role specification of feedback projections
+            for node, role in self.required_node_roles:
+                if (
+                    (node == projection.sender.owner and role == NodeRole.FEEDBACK_SENDER)
+                    or (node == projection.receiver.owner and role == NodeRole.FEEDBACK_RECEIVER)
+                ):
+                    feedback = True
+
             self.graph.add_component(projection, feedback=feedback)
 
             try:
diff --git a/tests/composition/test_composition.py b/tests/composition/test_composition.py
index e85810b219d..230af9f4c34 100644
--- a/tests/composition/test_composition.py
+++ b/tests/composition/test_composition.py
@@ -7362,6 +7362,20 @@ def test_inactive_terminal_projection(self):
 
         assert comp.nodes_to_roles[A] == {NodeRole.INPUT, NodeRole.OUTPUT, NodeRole.SINGLETON, NodeRole.ORIGIN, NodeRole.TERMINAL}
 
+    def test_feedback_projection_added_by_pathway(self):
+        A = pnl.ProcessingMechanism(name='A')
+        B = pnl.ProcessingMechanism(name='B')
+        C = pnl.ProcessingMechanism(name='C')
+
+        icomp = pnl.Composition(pathways=[C])
+        ocomp = pnl.Composition(pathways=[A, icomp, (B, pnl.NodeRole.FEEDBACK_SENDER), A])
+
+        assert ocomp.nodes_to_roles == {
+            A: {NodeRole.ORIGIN, NodeRole.INPUT, NodeRole.FEEDBACK_RECEIVER},
+            icomp: {NodeRole.INTERNAL},
+            B: {NodeRole.TERMINAL, NodeRole.OUTPUT, NodeRole.FEEDBACK_SENDER},
+        }
+
 
 class TestMisc: