Add validation to raise error when ChatMessageTrigger and entrypoint are both present

- Add ChatMessageTrigger to WorkflowTriggerType enum (CHAT_MESSAGE)
- Add validation in serialize() to raise WorkflowValidationError when both
  ChatMessageTrigger and entrypoint nodes are present (mutually exclusive)
- Add ChatMessageTrigger handling in _serialize_workflow_trigger()
- Add tests for the validation

Co-Authored-By: vincent@vellum.ai <0426vincent@gmail.com>

Author: devin-ai-integration[bot]

ee/vellum_ee/workflows/display/tests/workflow_serialization/test_chat_message_trigger_entrypoint_validation.py

@@ -0,0 +1,88 @@
+import pytest
+from typing import List
+
+from pydantic import Field
+
+from vellum.client.types import ChatMessage
+from vellum.workflows import BaseWorkflow
+from vellum.workflows.graph import Graph
+from vellum.workflows.inputs.base import BaseInputs
+from vellum.workflows.nodes.bases.base import BaseNode
+from vellum.workflows.references import LazyReference
+from vellum.workflows.state.base import BaseState
+from vellum.workflows.triggers.chat_message import ChatMessageTrigger
+from vellum_ee.workflows.display.utils.exceptions import WorkflowValidationError
+from vellum_ee.workflows.display.workflows.get_vellum_workflow_display_class import get_workflow_display
+
+
+class ChatState(BaseState):
+    chat_history: List[ChatMessage] = Field(default_factory=list)
+
+
+class SimpleNode(BaseNode):
+    class Outputs(BaseNode.Outputs):
+        response: str = "Hello!"
+
+
+class AnotherNode(BaseNode):
+    class Outputs(BaseNode.Outputs):
+        result: str = "Another!"
+
+
+def test_chat_message_trigger_with_entrypoint_raises_error():
+    """
+    Tests that serializing a workflow with both ChatMessageTrigger and an entrypoint raises an error.
+    """
+
+    # GIVEN a workflow with ChatMessageTrigger that also has a separate entrypoint (multiple subgraphs)
+    class SimpleChatTrigger(ChatMessageTrigger):
+        class Config(ChatMessageTrigger.Config):
+            output = LazyReference(lambda: WorkflowWithEntrypoint.Outputs.response)  # type: ignore[has-type]
+
+    class WorkflowWithEntrypoint(BaseWorkflow[BaseInputs, ChatState]):
+        graph = {
+            SimpleChatTrigger >> SimpleNode,
+            Graph.from_node(AnotherNode),
+        }
+
+        class Outputs(BaseWorkflow.Outputs):
+            response = SimpleNode.Outputs.response
+
+    # WHEN we try to serialize the workflow
+    # THEN it should raise a WorkflowValidationError
+    with pytest.raises(WorkflowValidationError) as exc_info:
+        get_workflow_display(workflow_class=WorkflowWithEntrypoint).serialize()
+
+    # AND the error message should indicate the mutual exclusivity
+    assert "ChatMessageTrigger and entrypoint nodes are mutually exclusive" in str(exc_info.value)
+
+
+def test_chat_message_trigger_without_entrypoint_does_not_raise_mutual_exclusivity_error():
+    """
+    Tests that serializing a workflow with only ChatMessageTrigger (no entrypoint) does not raise
+    the mutual exclusivity error.
+    """
+
+    # GIVEN a workflow with only ChatMessageTrigger (no entrypoint)
+    class SimpleChatTrigger(ChatMessageTrigger):
+        class Config(ChatMessageTrigger.Config):
+            output = LazyReference(lambda: ChatOnlyWorkflow.Outputs.response)  # type: ignore[has-type]
+
+    class ChatOnlyWorkflow(BaseWorkflow[BaseInputs, ChatState]):
+        graph = SimpleChatTrigger >> SimpleNode
+
+        class Outputs(BaseWorkflow.Outputs):
+            response = SimpleNode.Outputs.response
+
+    # WHEN we try to serialize the workflow
+    # THEN it should NOT raise a WorkflowValidationError about mutual exclusivity
+    # (it may raise other errors due to ChatMessageTrigger attribute serialization limitations)
+    try:
+        get_workflow_display(workflow_class=ChatOnlyWorkflow).serialize()
+    except WorkflowValidationError as e:
+        # If we get a WorkflowValidationError, it should NOT be about mutual exclusivity
+        assert "ChatMessageTrigger and entrypoint nodes are mutually exclusive" not in str(
+            e
+        ), f"Should not raise mutual exclusivity error for ChatMessageTrigger-only workflow, got: {e}"
+    except ValueError:
+        pass

ee/vellum_ee/workflows/display/workflows/base_workflow_display.py

@@ -274,6 +274,19 @@ def serialize(self) -> JsonObject:
         has_triggers = len(trigger_edges) > 0
         needs_entrypoint_node = has_manual_trigger or not has_triggers or len(non_trigger_entrypoint_nodes) > 0
 
+        # Check for ChatMessageTrigger - it's mutually exclusive with having an entrypoint node
+        chat_message_trigger_edges = [
+            edge for edge in trigger_edges if issubclass(edge.trigger_class, ChatMessageTrigger)
+        ]
+        has_chat_message_trigger = len(chat_message_trigger_edges) > 0
+
+        if has_chat_message_trigger and needs_entrypoint_node:
+            raise WorkflowValidationError(
+                message="ChatMessageTrigger and entrypoint nodes are mutually exclusive. "
+                "A workflow cannot have both a ChatMessageTrigger and an entrypoint node.",
+                workflow_class_name=self._workflow.__name__,
+            )
+
         entrypoint_node_id: Optional[UUID] = None
         entrypoint_node_source_handle_id: Optional[UUID] = None
         entrypoint_node_display = self.display_context.workflow_display.entrypoint_node_display