Fixed DefaultTopic TopicBufferFullMode Mapping (#8393)

Author: michaelstaib

src/HotChocolate/Core/src/Subscriptions/DefaultTopic.cs

@@ -38,7 +38,7 @@ protected DefaultTopic(
         Name = name ?? throw new ArgumentNullException(nameof(name));
         _channelOptions = new BoundedChannelOptions(capacity)
         {
-            FullMode = (BoundedChannelFullMode) (int) fullMode,
+            FullMode = fullMode.ToBoundedChannelFullMode()
         };
         _incoming = CreateUnbounded<TMessage>();
         _diagnosticEvents = diagnosticEvents;
@@ -54,7 +54,7 @@ protected DefaultTopic(
         Name = name ?? throw new ArgumentNullException(nameof(name));
         _channelOptions = new BoundedChannelOptions(capacity)
         {
-            FullMode = (BoundedChannelFullMode) (int) fullMode,
+            FullMode = fullMode.ToBoundedChannelFullMode()
         };
         _incoming = incomingMessages;
         _diagnosticEvents = diagnosticEvents;
@@ -108,7 +108,7 @@ public void Complete()
     }
 
     /// <summary>
-    /// Allows to subscribe to this topic. If the topic is already completed, this method will
+    /// Allows subscribing to this topic. If the topic is already completed, this method will
     /// return null.
     /// </summary>
     /// <returns>
@@ -266,7 +266,8 @@ private void DispatchMessages()
 
                 if (!allWritesSuccessful || iterations++ >= 8)
                 {
-                    // we will take a pause if we have dispatched 8 messages or if we could not dispatch all messages.
+                    // We will take a pause if we have dispatched 8 messages
+                    // or if we could not dispatch all messages.
                     // This will give time for subscribers to unsubscribe and
                     // others to hop on.
                     break;

src/HotChocolate/Core/src/Subscriptions/Extensions/TopicBufferFullModeHelper.cs

@@ -0,0 +1,19 @@
+using System.Threading.Channels;
+using HotChocolate.Subscriptions.Properties;
+
+namespace HotChocolate.Subscriptions;
+
+internal static class TopicBufferFullModeExtensions
+{
+    public static BoundedChannelFullMode ToBoundedChannelFullMode(this TopicBufferFullMode fullMode)
+        => fullMode switch
+        {
+            TopicBufferFullMode.DropNewest => BoundedChannelFullMode.DropNewest,
+            TopicBufferFullMode.DropOldest => BoundedChannelFullMode.DropOldest,
+            TopicBufferFullMode.DropWrite => BoundedChannelFullMode.DropWrite,
+            _ => throw new ArgumentOutOfRangeException(
+                nameof(fullMode),
+                fullMode,
+                Resources.ConvertFullMode_Value_NotSupported)
+        };
+}

src/HotChocolate/Core/src/Subscriptions/ITopic.cs

@@ -11,7 +11,7 @@ public interface ITopic : IDisposable
     public Type MessageType { get; }
 
     /// <summary>
-    /// Allows to complete a topic.
+    /// Allows completing a topic.
     /// </summary>
     void Complete();
 }

src/HotChocolate/Core/src/Subscriptions/Properties/Resources.Designer.cs

@@ -113,4 +113,7 @@
   <data name="InvalidMessageTypeException_Message" xml:space="preserve">
     <value>The topic already exists with a different message type. Topic message type: {0}. Requested message type: {1}.</value>
   </data>
+  <data name="TopicBufferFullModeExtensions_ConvertFullMode_The_specified_topic_buffer_full_mode_is_not_supported_" xml:space="preserve">
+    <value>The specified topic buffer full mode is not supported.</value>
+  </data>
 </root>