Implemented (un)marshalling for events

This fixes JSON (de)serialization of certain events.

2 files changed, 19 insertions, 3 deletions

diff --git a/src/apscheduler/eventbrokers/base.py b/src/apscheduler/eventbrokers/base.py
index 3aeee77..5f2ece1 100644
--- a/src/apscheduler/eventbrokers/base.py
+++ b/src/apscheduler/eventbrokers/base.py
@@ -56,11 +56,11 @@ class DistributedEventBrokerMixin:
     _logger: Logger
 
     def generate_notification(self, event: Event) -> bytes:
-        serialized = self.serializer.serialize(attrs.asdict(event))
+        serialized = self.serializer.serialize(event.marshal(self.serializer))
         return event.__class__.__name__.encode("ascii") + b" " + serialized
 
     def generate_notification_str(self, event: Event) -> str:
-        serialized = self.serializer.serialize(attrs.asdict(event))
+        serialized = self.serializer.serialize(event.marshal(self.serializer))
         return event.__class__.__name__ + " " + b64encode(serialized).decode("ascii")
 
     def _reconstitute_event(self, event_type: str, serialized: bytes) -> Event | None:
@@ -85,7 +85,7 @@ class DistributedEventBrokerMixin:
             return None
 
         try:
-            return event_class(**kwargs)
+            return event_class.unmarshal(self.serializer, kwargs)
         except Exception:
             self._logger.exception("Error reconstituting event of type %s", event_type)
             return None
diff --git a/src/apscheduler/events.py b/src/apscheduler/events.py
index 408089e..6aba147 100644
--- a/src/apscheduler/events.py
+++ b/src/apscheduler/events.py
@@ -2,21 +2,37 @@ from __future__ import annotations
 
 from datetime import datetime, timezone
 from functools import partial
+from typing import Any
 from uuid import UUID
 
 import attrs
 from attrs.converters import optional
 
+from . import abc
 from .converters import as_aware_datetime, as_uuid
 from .enums import JobOutcome
 
 
+def serialize(inst, field, value):
+    if isinstance(value, frozenset):
+        return list(value)
+
+    return value
+
+
 @attrs.define(kw_only=True, frozen=True)
 class Event:
     timestamp: datetime = attrs.field(
         factory=partial(datetime.now, timezone.utc), converter=as_aware_datetime
     )
 
+    def marshal(self, serializer: abc.Serializer) -> dict[str, Any]:
+        return attrs.asdict(self, value_serializer=serialize)
+
+    @classmethod
+    def unmarshal(cls, serializer: abc.Serializer, marshalled: dict[str, Any]) -> Event:
+        return cls(**marshalled)
+
 
 #
 # Data store events