feat(api): automatically NODE_TYPE_CLASSES_MAPPING generation from node class definitions (#28525)

api/extensions/ext_forward_refs.py

@@ -0,0 +1,49 @@
+import logging
+
+from dify_app import DifyApp
+
+
+def is_enabled() -> bool:
+    return True
+
+
+def init_app(app: DifyApp):
+    """Resolve Pydantic forward refs that would otherwise cause circular imports.
+
+    Rebuilds models in core.app.entities.app_invoke_entities with the real TraceQueueManager type.
+    Safe to run multiple times.
+    """
+    logger = logging.getLogger(__name__)
+    try:
+        from core.app.entities.app_invoke_entities import (
+            AdvancedChatAppGenerateEntity,
+            AgentChatAppGenerateEntity,
+            AppGenerateEntity,
+            ChatAppGenerateEntity,
+            CompletionAppGenerateEntity,
+            ConversationAppGenerateEntity,
+            EasyUIBasedAppGenerateEntity,
+            RagPipelineGenerateEntity,
+            WorkflowAppGenerateEntity,
+        )
+        from core.ops.ops_trace_manager import TraceQueueManager  # heavy import, do it at startup only
+
+        ns = {"TraceQueueManager": TraceQueueManager}
+        for Model in (
+            AppGenerateEntity,
+            EasyUIBasedAppGenerateEntity,
+            ConversationAppGenerateEntity,
+            ChatAppGenerateEntity,
+            CompletionAppGenerateEntity,
+            AgentChatAppGenerateEntity,
+            AdvancedChatAppGenerateEntity,
+            WorkflowAppGenerateEntity,
+            RagPipelineGenerateEntity,
+        ):
+            try:
+                Model.model_rebuild(_types_namespace=ns)
+            except Exception as e:
+                logger.debug("model_rebuild skipped for %s: %s", Model.__name__, e)
+    except Exception as e:
+        # Don't block app startup; just log at debug level.
+        logger.debug("ext_forward_refs init skipped: %s", e)