fix: honor live scheduling revisions at dispatch

src/wf_scheduling/poll.py

@@ -141,6 +141,18 @@ class Scheduler:
             else FileScheduleHistoryRecorder(schedule_store)
         )
         self._poll_cursor = 0
+        self._source_definitions: dict[str, Any] = {}
+
+    def set_source_definitions(self, definitions: dict[str, Any]) -> None:
+        """Record the trigger definitions used to build managed sources.
+
+        The service refreshes this map at tick start. A schedule edit can
+        commit between that refresh and a schedule's fresh read; the poller
+        then rebuilds only that schedule's source before resolving an instant.
+        Direct Scheduler tests without this service-owned map keep their
+        injected source collaborators unchanged.
+        """
+        self._source_definitions = dict(definitions)
 
     def _require_ownership(self) -> None:
         """Reject schedule mutation/dispatch without proven live ownership.
@@ -741,12 +753,23 @@ class Scheduler:
             consumed = self.schedule_store.get_consumed(sched.id) or EPOCH
             self.schedule_store.save_consumed(sched.id, max(consumed, now))
             return "paused"
-        try:
-            src = self.sources[sched.id]
-        except KeyError as exc:
-            raise InvalidScheduleDefinitionError(
-                f"no occurrence source for schedule {sched.id!r}"
-            ) from exc
+        source_definition = self._source_definitions.get(sched.id)
+        if source_definition is not None and source_definition != sched.trigger:
+            try:
+                src = source_for_trigger(sched.trigger)
+            except Exception as exc:
+                raise InvalidScheduleDefinitionError(
+                    f"invalid trigger for schedule {sched.id!r}: {exc}"
+                ) from exc
+            self.sources[sched.id] = src
+            self._source_definitions[sched.id] = sched.trigger
+        else:
+            try:
+                src = self.sources[sched.id]
+            except KeyError as exc:
+                raise InvalidScheduleDefinitionError(
+                    f"no occurrence source for schedule {sched.id!r}"
+                ) from exc
         consumed = self.schedule_store.get_consumed(sched.id) or EPOCH
         if consumed > now:
             return "clock-rollback-held"