fix: let unchanged() see ZMQ reads in Python

concore_base.py

@@ -275,6 +275,7 @@ def read(mod, port_identifier, name, initstr_val):
         zmq_p = mod.zmq_ports[port_identifier]
         try:
             message = zmq_p.recv_json_with_retry()
+            mod.s += str(message)  # so unchanged() sees the new data
             # Strip simtime prefix if present (mirroring file-based read behavior)
             if isinstance(message, list) and len(message) > 0:
                 first_element = message[0]

tests/test_concore.py

@@ -230,6 +230,22 @@ def test_unchanged_returns_false_if_diff(self):
         assert concore.unchanged() is False
         assert concore.olds == "new"
 
+    def test_unchanged_returns_false_after_zmq_read(self, monkeypatch):
+        """Issue #612 – a successful ZMQ read must count as new data."""
+        import concore
+
+        class DummyPort:
+            def recv_json_with_retry(self):
+                return [1.0, 10.0]
+
+        monkeypatch.setitem(concore.zmq_ports, "test_zmq", DummyPort())
+        concore.s = ""
+        concore.olds = ""
+
+        assert concore.unchanged() is True
+        concore.read("test_zmq", "u", "[0]")
+        assert concore.unchanged() is False
+
 
 class TestParseParams:
     def test_simple_key_value_pairs(self):

tests/test_concoredocker.py

@@ -236,6 +236,21 @@ def recv_json_with_retry(self):
 
         assert concoredocker.simtime == 5.0
 
+    def test_read_breaks_unchanged(self, monkeypatch):
+        import concoredocker
+
+        class DummyPort:
+            def recv_json_with_retry(self):
+                return [1.0, 10.0]
+
+        concoredocker.zmq_ports["test_zmq"] = DummyPort()
+        monkeypatch.setattr(concoredocker, "s", "")
+        monkeypatch.setattr(concoredocker, "olds", "")
+
+        assert concoredocker.unchanged() is True
+        concoredocker.read("test_zmq", "data", "[0]")
+        assert concoredocker.unchanged() is False
+
     def test_write_read_roundtrip(self):
         import concoredocker