fix RetrievalMethod StrEnum (#26768)

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Co-authored-by: crazywoola <100913391+crazywoola@users.noreply.github.com>

api/core/workflow/enums.py

@@ -1,7 +1,7 @@
-from enum import Enum, StrEnum
+from enum import StrEnum
 
 
-class NodeState(Enum):
+class NodeState(StrEnum):
     """State of a node or edge during workflow execution."""
 
     UNKNOWN = "unknown"

api/core/workflow/graph_engine/layers/execution_limits.py

@@ -10,7 +10,7 @@ When limits are exceeded, the layer automatically aborts execution.
 
 import logging
 import time
-from enum import Enum
+from enum import StrEnum
 from typing import final
 
 from typing_extensions import override
@@ -24,7 +24,7 @@ from core.workflow.graph_events import (
 from core.workflow.graph_events.node import NodeRunFailedEvent, NodeRunSucceededEvent
 
 
-class LimitType(Enum):
+class LimitType(StrEnum):
     """Types of execution limits that can be exceeded."""
 
     STEP_LIMIT = "step_limit"

api/core/workflow/nodes/knowledge_index/entities.py

@@ -2,6 +2,7 @@ from typing import Literal, Union
 
 from pydantic import BaseModel
 
+from core.rag.retrieval.retrieval_methods import RetrievalMethod
 from core.workflow.nodes.base import BaseNodeData
 
 
@@ -63,7 +64,7 @@ class RetrievalSetting(BaseModel):
     Retrieval Setting.
     """
 
-    search_method: Literal["semantic_search", "keyword_search", "full_text_search", "hybrid_search"]
+    search_method: RetrievalMethod
     top_k: int
     score_threshold: float | None = 0.5
     score_threshold_enabled: bool = False