From af4b65b295050bd838d08c9647fc8d49e9c8aebd Mon Sep 17 00:00:00 2001
From: zyssyz123 <916125788@qq.com>
Date: Fri, 17 Jul 2026 16:42:58 +0800
Subject: [PATCH] fix(agent): allow dangling refs in workflow drafts (#39192)

---
 .../workflow/nodes/agent_v2/validators.py     | 29 +++++++++---
 .../nodes/agent_v2/test_validators.py         | 45 +++++++++++++++++++
 2 files changed, 68 insertions(+), 6 deletions(-)

diff --git a/api/core/workflow/nodes/agent_v2/validators.py b/api/core/workflow/nodes/agent_v2/validators.py
index 83dce82a58d..7e3969d8a16 100644
--- a/api/core/workflow/nodes/agent_v2/validators.py
+++ b/api/core/workflow/nodes/agent_v2/validators.py
@@ -61,16 +61,33 @@ class WorkflowAgentNodeValidator:
 
     @classmethod
     def validate_draft_workflow(cls, *, session: Session, workflow: Workflow) -> None:
-        cls._validate_workflow(session=session, workflow=workflow, require_binding=False)
+        cls._validate_workflow(
+            session=session,
+            workflow=workflow,
+            require_binding=False,
+            validate_previous_node_topology=False,
+        )
 
     @classmethod
     def validate_published_workflow(cls, *, session: Session, workflow: Workflow) -> None:
-        cls._validate_workflow(session=session, workflow=workflow, require_binding=True)
+        cls._validate_workflow(
+            session=session,
+            workflow=workflow,
+            require_binding=True,
+            validate_previous_node_topology=True,
+        )
 
     @classmethod
-    def _validate_workflow(cls, *, session: Session, workflow: Workflow, require_binding: bool) -> None:
+    def _validate_workflow(
+        cls,
+        *,
+        session: Session,
+        workflow: Workflow,
+        require_binding: bool,
+        validate_previous_node_topology: bool,
+    ) -> None:
         graph = workflow.graph_dict
-        topology = _WorkflowGraphTopology.from_graph(graph)
+        topology = _WorkflowGraphTopology.from_graph(graph) if validate_previous_node_topology else None
         for node_id, node_data in cls.iter_agent_v2_nodes(graph):
             cls._validate_node_schema(node_id=node_id, node_data=node_data)
             binding = cls._find_binding(
@@ -185,12 +202,12 @@ class WorkflowAgentNodeValidator:
                 raise WorkflowAgentNodeValidationError(
                     f"Workflow Agent node {binding.node_id} has invalid previous node output ref."
                 )
-            if topology is None:
-                continue
             if len(selector) < 2:
                 raise WorkflowAgentNodeValidationError(
                     f"Workflow Agent node {binding.node_id} has incomplete previous node output ref."
                 )
+            if topology is None:
+                continue
             source_node_id = selector[0]
             if not topology.has_node(source_node_id):
                 raise WorkflowAgentNodeValidationError(
diff --git a/api/tests/unit_tests/core/workflow/nodes/agent_v2/test_validators.py b/api/tests/unit_tests/core/workflow/nodes/agent_v2/test_validators.py
index 0c8169943f9..237ab8ebe3b 100644
--- a/api/tests/unit_tests/core/workflow/nodes/agent_v2/test_validators.py
+++ b/api/tests/unit_tests/core/workflow/nodes/agent_v2/test_validators.py
@@ -187,6 +187,51 @@ def test_draft_validation_allows_unbound_agent_node():
     )
 
 
+def test_draft_validation_allows_missing_previous_node():
+    node_job = WorkflowNodeJobConfig.model_validate(
+        {"previous_node_output_refs": [{"node_id": "missing-node", "output": "text"}]}
+    )
+    session = Mock()
+    session.scalar.side_effect = [_binding(node_job), _agent(), _snapshot()]
+
+    WorkflowAgentNodeValidator.validate_draft_workflow(
+        session=session,
+        workflow=_workflow(_graph([{"source": "start", "target": "agent-node"}])),
+    )
+
+
+def test_draft_validation_allows_non_upstream_previous_output_ref():
+    node_job = WorkflowNodeJobConfig.model_validate(
+        {"previous_node_output_refs": [{"node_id": "later-node", "output": "text"}]}
+    )
+    session = Mock()
+    session.scalar.side_effect = [_binding(node_job), _agent(), _snapshot()]
+
+    WorkflowAgentNodeValidator.validate_draft_workflow(
+        session=session,
+        workflow=_workflow(
+            _graph(
+                [
+                    {"source": "start", "target": "agent-node"},
+                    {"source": "agent-node", "target": "later-node"},
+                ]
+            )
+        ),
+    )
+
+
+def test_draft_validation_rejects_incomplete_previous_output_ref():
+    node_job = WorkflowNodeJobConfig.model_validate({"previous_node_output_refs": [{"selector": ["previous-node"]}]})
+    session = Mock()
+    session.scalar.side_effect = [_binding(node_job), _agent(), _snapshot()]
+
+    with pytest.raises(WorkflowAgentNodeValidationError, match="incomplete previous node output ref"):
+        WorkflowAgentNodeValidator.validate_draft_workflow(
+            session=session,
+            workflow=_workflow(_graph([{"source": "start", "target": "agent-node"}])),
+        )
+
+
 def test_publish_validation_requires_binding():
     session = Mock()
     session.scalar.return_value = None