Set EventSlice identity from event stream

JasperFx · Feb 6, 2025 · 687ec5f · 687ec5f
1 parent 87aad94
commit 687ec5f
Show file tree

Hide file tree

Showing 2 changed files with 4 additions and 6 deletions.
diff --git a/src/EventSourcingTests/FetchForWriting/fetching_live_aggregates_for_writing.cs b/src/EventSourcingTests/FetchForWriting/fetching_live_aggregates_for_writing.cs
@@ -380,9 +380,6 @@ public async Task using_a_custom_projection_that_has_string_as_id_fetch_latest()
         {
             opts.Projections.Add(new ExplicitCounterThatHasStringId(), ProjectionLifecycle.Async);
             opts.Events.StreamIdentity = StreamIdentity.AsString;
-            //opts.Schema.For<SimpleAggregateAsString>()
-            //    .IdStrategy(new String2IdGeneration()); // This works as a workaround for this bug. But it should not be necessary
-            // What goes wrong? Before the aggregate gets the id assigned from the event stream, code passes a .Store() that tries to assign id by strategy
         });
 
         var streamId = $"simple|{Guid.NewGuid()}";

diff --git a/src/Marten/Events/Aggregation/CustomProjection.cs b/src/Marten/Events/Aggregation/CustomProjection.cs
@@ -375,7 +375,9 @@ async ValueTask<TDoc> ILiveAggregator<TDoc>.BuildAsync(IReadOnlyList<IEvent> eve
 
         var documentSessionBase = session as DocumentSessionBase ?? (DocumentSessionBase)session.DocumentStore.LightweightSession();
 
-        var slice = new EventSlice<TDoc, TId>(default, session, events);
+        var latestEvent = events.Last();
+        var streamId = IdentityFromEvent(latestEvent);
+        var slice = new EventSlice<TDoc, TId>(streamId, session, events);
         if (Lifecycle == ProjectionLifecycle.Live)
         {
             slice.Aggregate = await BuildAsync(session, slice.Aggregate, slice.Events()).ConfigureAwait(false);
@@ -420,8 +422,7 @@ public IAggregateCache<TId, TDoc> CacheFor(Tenant tenant)
 
     public TId IdentityFromEvent(IEvent e)
     {
-        // TODO -- come back here.
-        throw new NotImplementedException();
+        return e.StreamKey.To<TId>() ?? e.StreamId.To<TId>();
     }
 }