fix(langchain): set cost to zero on errors (#1328)

Author: hassiebp

langfuse/langchain/CallbackHandler.py

@@ -218,6 +218,7 @@ def on_retriever_error(
                     level="ERROR",
                     status_message=str(error),
                     input=kwargs.get("inputs"),
+                    cost_details={"total": 0},
                 ).end()
 
         except Exception as e:
@@ -527,6 +528,7 @@ def on_chain_error(
                     ),
                     status_message=str(error) if level else None,
                     input=kwargs.get("inputs"),
+                    cost_details={"total": 0},
                 ).end()
 
         except Exception as e:
@@ -733,6 +735,7 @@ def on_tool_error(
                     status_message=str(error),
                     level="ERROR",
                     input=kwargs.get("inputs"),
+                    cost_details={"total": 0},
                 ).end()
 
         except Exception as e:
@@ -913,6 +916,7 @@ def on_llm_error(
                     status_message=str(error),
                     level="ERROR",
                     input=kwargs.get("inputs"),
+                    cost_details={"total": 0},
                 ).end()
 
         except Exception as e: