fix: accept operations that reference an inline channel message

The V3 OperationMessages rule compared from the channel message's side,
so an inline channel message used object equality and never matched the
operation's reference, failing valid documents. It now compares from
both sides.

Author: VisualBean

src/ByteBard.AsyncAPI/Validation/Rules/AsyncApiOperationRules.cs

@@ -92,6 +92,8 @@ private static bool AllOperationsMessagesReferencesChannelMessages(
 
         private static bool OperationMessageReferencesAnyChannelMessage(
             AsyncApiMessageReference operationMessage, ICollection<AsyncApiMessage> channelMessages) =>
-            channelMessages.Any(channelMessage => channelMessage.Equals(operationMessage));
+            // Only references know how to compare themselves to their target, so an inline channel message
+            // has to be compared from the operation's side, and a referenced one from the channel's side.
+            channelMessages.Any(channelMessage => operationMessage.Equals(channelMessage) || channelMessage.Equals(operationMessage));
     }
 }

test/ByteBard.AsyncAPI.Tests/Validation/ValidationRuleTests.cs

@@ -218,6 +218,107 @@ public void V3_OperationMessage_NotReferencingARootChannel_DiagnosticsError()
     diagnostic.Errors.First().Pointer.Should().Be("#/operations/onMessageReceived");
   }
 
+  [Test]
+  public void V3_OperationMessage_ReferencingAnInlineChannelMessage_Passes()
+  {
+    var input =
+      """
+      asyncapi: 3.0.0
+      info:
+        title: Chat Application
+        version: 1.0.0
+      channels:
+        chatPersonId:
+          address: chat.{personId}
+          messages:
+            messageReceived:
+              name: text
+              payload:
+                type: string
+      operations:
+        onMessageReceived:
+          title: Message received
+          action: receive
+          channel:
+            $ref: '#/channels/chatPersonId'
+          messages:
+            - $ref: '#/channels/chatPersonId/messages/messageReceived'
+      """;
+
+    new AsyncApiStringReader().Read(input, out var diagnostic);
+    diagnostic.Errors.Should().BeEmpty();
+  }
+
+  [Test]
+  public void V3_OperationMessage_ReferencingAChannelMessageThatReferencesAComponent_Passes()
+  {
+    var input =
+      """
+      asyncapi: 3.0.0
+      info:
+        title: Chat Application
+        version: 1.0.0
+      channels:
+        chatPersonId:
+          address: chat.{personId}
+          messages:
+            messageReceived:
+              $ref: '#/components/messages/messageReceived'
+      operations:
+        onMessageReceived:
+          title: Message received
+          action: receive
+          channel:
+            $ref: '#/channels/chatPersonId'
+          messages:
+            - $ref: '#/channels/chatPersonId/messages/messageReceived'
+      components:
+        messages:
+          messageReceived:
+            name: text
+            payload:
+              type: string
+      """;
+
+    new AsyncApiStringReader().Read(input, out var diagnostic);
+    diagnostic.Errors.Should().BeEmpty();
+  }
+
+  [Test]
+  public void V3_OperationMessage_ReferencingTheComponentAChannelMessageReferences_Passes()
+  {
+    var input =
+      """
+      asyncapi: 3.0.0
+      info:
+        title: Chat Application
+        version: 1.0.0
+      channels:
+        chatPersonId:
+          address: chat.{personId}
+          messages:
+            messageReceived:
+              $ref: '#/components/messages/messageReceived'
+      operations:
+        onMessageReceived:
+          title: Message received
+          action: receive
+          channel:
+            $ref: '#/channels/chatPersonId'
+          messages:
+            - $ref: '#/components/messages/messageReceived'
+      components:
+        messages:
+          messageReceived:
+            name: text
+            payload:
+              type: string
+      """;
+
+    new AsyncApiStringReader().Read(input, out var diagnostic);
+    diagnostic.Errors.Should().BeEmpty();
+  }
+
   [Test]
   [TestCase("chat")]
   [TestCase("/some/chat/{personId}")]