feat: add tests and migration docs for using message name for anonymous payload schemas

docs/migrations/version-5-to-6.md

@@ -110,6 +110,61 @@ Generated model: `AnonymousSchema_1` or `<anonymous-message-1>Payload`
 **After (v6):**
 Generated model: `UserSignedupPayload` (derived from channel path `/user/signedup`)
 
+#### Named messages with anonymous payloads (fixes #1996)
+
+When using named messages in `components/messages` with inline (anonymous) payload schemas, the generated model now uses the message name instead of generic `AnonymousSchema_1`.
+
+**Before (v5):**
+
+```yaml
+asyncapi: 2.2.0
+info:
+  title: Account Service
+  version: 1.0.0
+channels:
+  user/signedup:
+    subscribe:
+      message:
+        $ref: '#/components/messages/UserSignedUp'
+components:
+  messages:
+    UserSignedUp:
+      payload:
+        type: object
+        properties:
+          displayName:
+            type: string
+          email:
+            type: string
+            format: email
+```
+
+Generated model: `AnonymousSchema_1`
+
+**After (v6):**
+
+Generated model: `UserSignedUpPayload` (derived from message name `UserSignedUp`)
+
+This also works for AsyncAPI v3 named messages:
+
+```yaml
+asyncapi: 3.0.0
+channels:
+  userSignedUp:
+    address: user/signedup
+    messages:
+      UserSignedUpMessage:
+        payload:
+          type: object
+          properties:
+            displayName:
+              type: string
+            email:
+              type: string
+```
+
+Generated model: `UserSignedUpMessagePayload` (derived from message name `UserSignedUpMessage`)
+
 #### Hierarchical naming for nested schemas
 
 Nested schemas in properties, `allOf`, `oneOf`, `anyOf`, `dependencies`, and `definitions` now receive hierarchical names based on their parent schema and property path.

src/processors/AsyncAPIInputProcessor.ts

@@ -334,14 +334,15 @@ export class AsyncAPIInputProcessor extends AbstractInputProcessor {
 
                 // Add each individual message payload as a separate model
                 const messageId = message.id();
-                // Use message ID if available, otherwise use channel name
+                const messageName = message.name();
+                // Use message ID if available, then message name, otherwise use channel name
                 const contextId =
                   messageId &&
                   !messageId.includes(
                     AsyncAPIInputProcessor.ANONYMOUS_MESSAGE_PREFIX
                   )
                     ? messageId
-                    : contextChannelName;
+                    : messageName || contextChannelName;
                 const messageContext: SchemaContext = contextId
                   ? { messageId: contextId }
                   : {};
@@ -364,14 +365,15 @@ export class AsyncAPIInputProcessor extends AbstractInputProcessor {
               if (payload) {
                 // Use message ID as context for better naming
                 const messageId = message.id();
-                // Use message ID if available, otherwise use channel name
+                const messageName = message.name();
+                // Use message ID if available, then message name, otherwise use channel name
                 const contextId =
                   messageId &&
                   !messageId.includes(
                     AsyncAPIInputProcessor.ANONYMOUS_MESSAGE_PREFIX
                   )
                     ? messageId
-                    : contextChannelName;
+                    : messageName || contextChannelName;
                 const messageContext: SchemaContext = contextId
                   ? { messageId: contextId }
                   : {};
@@ -398,10 +400,11 @@ export class AsyncAPIInputProcessor extends AbstractInputProcessor {
       for (const message of doc.allMessages()) {
         const payload = message.payload();
         if (payload) {
-          // Use message id with 'Payload' suffix as the inferred name for the payload schema
+          // Use message id or message name with 'Payload' suffix as the inferred name for the payload schema
           // This avoids potential collisions with component schemas that might have the same name
-          const messageName = message.id()
-            ? `${message.id()}Payload`
+          const messageIdentifier = message.id() || message.name();
+          const messageName = messageIdentifier
+            ? `${messageIdentifier}Payload`
             : undefined;
           addToInputModel(payload, messageName);
         }

test/processors/AsyncAPIInputProcessor.spec.ts

@@ -1392,6 +1392,162 @@
       expect(commonInputModel.models['EventsStreamPayload']).toBeDefined();
     });
 
+    test('should use message name instead of AnonymousSchema for named message with anonymous payload (issue #1996)', async () => {
+      // This is the exact scenario from issue #1996
+      // When a message is defined in components/messages with a name (e.g., UserSignedUp)
+      // but its payload is an anonymous inline schema, the generated model should use
+      // the message name instead of AnonymousSchema_1
+      const doc = {
+        asyncapi: '2.2.0',
+        info: {
+          title: 'Account Service',
+          version: '1.0.0',
+          description:
+            'This service is in charge of processing user signups'
+        },
+        channels: {
+          'user/signedup': {
+            subscribe: {
+              message: {
+                $ref: '#/components/messages/UserSignedUp'
+              }
+            }
+          }
+        },
+        components: {
+          messages: {
+            UserSignedUp: {
+              payload: {
+                type: 'object',
+                properties: {
+                  displayName: {
+                    type: 'string',
+                    description: 'Name of the user'
+                  },
+                  email: {
+                    type: 'string',
+                    format: 'email',
+                    description: 'Email of the user'
+                  }
+                }
+              }
+            }
+          }
+        }
+      };
+      const processor = new AsyncAPIInputProcessor();
+      const commonInputModel = await processor.process(doc);
+      const modelNames = Object.keys(commonInputModel.models);
+
+      // Should NOT generate AnonymousSchema_1 as the model name
+      const anonymousModels = modelNames.filter((name) =>
+        name.toLowerCase().includes('anonymous')
+      );
+      expect(anonymousModels).toHaveLength(0);
+
+      // Should generate a meaningful model name derived from message or channel context
+      expect(modelNames.length).toBeGreaterThan(0);
+    });
+
+    test('should use message name for anonymous payload in v3 with named messages', async () => {
+      const doc = {
+        asyncapi: '3.0.0',
+        info: { title: 'Account Service', version: '1.0.0' },
+        channels: {
+          userSignedUp: {
+            address: 'user/signedup',
+            messages: {
+              UserSignedUpMessage: {
+                payload: {
+                  type: 'object',
+                  properties: {
+                    displayName: { type: 'string' },
+                    email: { type: 'string', format: 'email' }
+                  }
+                }
+              }
+            }
+          }
+        },
+        operations: {
+          onUserSignedUp: {
+            action: 'receive',
+            channel: { $ref: '#/channels/userSignedUp' },
+            messages: [
+              {
+                $ref: '#/channels/userSignedUp/messages/UserSignedUpMessage'
+              }
+            ]
+          }
+        }
+      };
+      const processor = new AsyncAPIInputProcessor();
+      const commonInputModel = await processor.process(doc);
+      const modelNames = Object.keys(commonInputModel.models);
+
+      // Should NOT generate AnonymousSchema as the model name
+      const anonymousModels = modelNames.filter((name) =>
+        name.toLowerCase().includes('anonymous')
+      );
+      expect(anonymousModels).toHaveLength(0);
+
+      // Should use the message name for payload naming
+      expect(
+        commonInputModel.models['UserSignedUpMessagePayload']
+      ).toBeDefined();
+    });
+
+    test('should use message name for multiple named messages with anonymous payloads', async () => {
+      const doc = {
+        asyncapi: '2.0.0',
+        info: { title: 'Test', version: '1.0.0' },
+        channels: {
+          events: {
+            subscribe: {
+              message: {
+                oneOf: [
+                  {
+                    name: 'UserCreated',
+                    payload: {
+                      type: 'object',
+                      properties: {
+                        userId: { type: 'string' }
+                      }
+                    }
+                  },
+                  {
+                    name: 'UserUpdated',
+                    payload: {
+                      type: 'object',
+                      properties: {
+                        userId: { type: 'string' },
+                        updatedFields: {
+                          type: 'array',
+                          items: { type: 'string' }
+                        }
+                      }
+                    }
+                  }
+                ]
+              }
+            }
+          }
+        }
+      };
+      const processor = new AsyncAPIInputProcessor();
+      const commonInputModel = await processor.process(doc);
+      const modelNames = Object.keys(commonInputModel.models);
+
+      // Should generate models without AnonymousSchema naming
+      expect(modelNames.length).toBeGreaterThan(0);
+      // Should have the oneOf wrapper for the channel
+      const anonymousModels = modelNames.filter((name) =>
+        name.toLowerCase().includes('anonymousschema')
+      );
+      // Anonymous schema naming should be avoided where possible
+      expect(anonymousModels.length).toBeLessThanOrEqual(0);
+    });
+
     test('should handle schema with only property name in context', async () => {
       const { document } = await parser.parse(
         JSON.stringify({