warning when there are async projections but no daemon. Closes GH-2509

docs/configuration/storeoptions.md

@@ -15,7 +15,7 @@ public static DocumentStore For(Action<StoreOptions> configure)
     return new DocumentStore(options);
 }
 ```
-<sup><a href='https://github.com/JasperFx/marten/blob/master/src/Marten/DocumentStore.cs#L472-L482' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_documentstore.for' title='Start of snippet'>anchor</a></sup>
+<sup><a href='https://github.com/JasperFx/marten/blob/master/src/Marten/DocumentStore.cs#L490-L500' title='Snippet source file'>snippet source</a> | <a href='#snippet-sample_documentstore.for' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
 The major parts of `StoreOptions` are shown in the class diagram below:

src/Marten/DocumentStore.cs

@@ -1,13 +1,17 @@
 #nullable enable
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using System.Transactions;
+using JasperFx.Core;
 using JasperFx.Core.Reflection;
 using Marten.Events;
 using Marten.Events.Daemon;
 using Marten.Events.Daemon.HighWater;
+using Marten.Events.Daemon.Resiliency;
+using Marten.Events.Projections;
 using Marten.Exceptions;
 using Marten.Internal.Sessions;
 using Marten.Schema;
@@ -59,6 +63,20 @@ public DocumentStore(StoreOptions options)
         _identityMapCompiledQueries = new CompiledQueryCollection(DocumentTracking.IdentityOnly, this);
         _dirtyTrackedCompiledQueries = new CompiledQueryCollection(DocumentTracking.DirtyTracking, this);
         _queryOnlyCompiledQueries = new CompiledQueryCollection(DocumentTracking.QueryOnly, this);
+
+        warnIfAsyncDaemonIsDisabledWithAsyncProjections();
+    }
+
+    private void warnIfAsyncDaemonIsDisabledWithAsyncProjections()
+    {
+        if (Options.Projections.HasAnyAsyncProjections() && Options.Projections.AsyncMode == DaemonMode.Disabled)
+        {
+            Console.WriteLine("Warning: The async daemon is disabled.");
+            var asyncProjectionList =
+                Options.Projections.All.Where(x => x.Lifecycle == ProjectionLifecycle.Async).Select(x => x.ToString())!
+                    .Join(", ");
+            Console.WriteLine($"Projections {asyncProjectionList} will not be executed without the async daemon enabled");
+        }
     }
 
     public ITenancy Tenancy => Options.Tenancy;