fixes

src/psygnal/_evented_model_v1.py

@@ -366,7 +366,7 @@ def __setattr__(self, name: str, value: Any) -> None:
         if (
             len(signal_instance) < 2  # the signal itself has no listeners
             and not deps_with_callbacks  # no dependent properties with listeners
-            and not len(self._events)  # no listeners on the SignalGroup
+            and not len(self._events._psygnal_relay)  # no listeners on the SignalGroup
         ):
             return self._super_setattr_(name, value)
 

src/psygnal/_evented_model_v2.py

@@ -352,7 +352,7 @@ def __setattr__(self, name: str, value: Any) -> None:
         if (
             len(signal_instance) < 2  # the signal itself has no listeners
             and not deps_with_callbacks  # no dependent properties with listeners
-            and not len(self._events)  # no listeners on the SignalGroup
+            and not len(self._events._psygnal_relay)  # no listeners on the SignalGroup
         ):
             return self._super_setattr_(name, value)
 

src/psygnal/_signal.py

@@ -1123,7 +1123,19 @@ def __getstate__(self) -> dict:
         )
         dd = {slot: getattr(self, slot) for slot in attrs}
         dd["_instance"] = self._instance()
-        dd["_slots"] = [x for x in self._slots if isinstance(x, StrongFunction)]
+        dd["_slots"] = [
+            x
+            for x in self._slots
+            if (
+                isinstance(x, StrongFunction)
+                # HACK
+                # this is a hack to retain the ability of a deep-copied signal group
+                # to connect to all signals in the group.
+                # reconsider this mechanism.  It could also be achieved more directly
+                # as a special __deepcopy__ method on SignalGroup
+                or getattr(x, "_obj_qualname", None) == "SignalRelay._slot_relay"
+            )
+        ]
         if len(self._slots) > len(dd["_slots"]):
             warnings.warn(
                 "Pickling a SignalInstance does not copy connected weakly referenced "

src/psygnal/utils.py

@@ -7,7 +7,7 @@
 from typing import Any, Callable, Generator, Iterator
 from warnings import warn
 
-from ._group2 import EmissionInfo, SignalGroup
+from ._group2 import EmissionInfo, SignalGroup, SignalRelay
 from ._signal import SignalInstance
 
 __all__ = ["monitor_events", "iter_signal_instances"]
@@ -58,6 +58,10 @@ def monitor_events(
             )
         disconnectors = set()
         for siginst in iter_signal_instances(obj, include_private_attrs):
+            if isinstance(siginst, SignalRelay):
+                # TODO: ... but why?
+                continue
+
             if _old_api:
 
                 def _report(*args: Any, signal: SignalInstance = siginst) -> None: