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Chatconv agent: output parser exception (#4923)

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the output parser form chat conversational agent now raises
`OutputParserException` like the rest.

The `raise OutputParserExeption(...) from e` form also carries through
the original error details on what went wrong.

I added the `ValueError` as a base class to `OutputParserException` to
avoid breaking code that was relying on `ValueError` as a way to catch
exceptions from the agent. So catching ValuError still works. Not sure
if this is a good idea though ?
This commit is contained in:
Chakib Ben Ziane 2023-05-19 01:20:35 +02:00 committed by GitHub
parent a9bb3147d7
commit 5525b704cc
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 23 additions and 20 deletions
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41
langchain/agents/conversational_chat/output_parser.py
View File

@ -5,7 +5,7 @@ from typing import Union
from langchain.agents import AgentOutputParser from langchain.agents import AgentOutputParser
from langchain.agents.conversational_chat.prompt import FORMAT_INSTRUCTIONS from langchain.agents.conversational_chat.prompt import FORMAT_INSTRUCTIONS
from langchain.schema import AgentAction, AgentFinish from langchain.schema import AgentAction, AgentFinish, OutputParserException
class ConvoOutputParser(AgentOutputParser): class ConvoOutputParser(AgentOutputParser):
@ -13,24 +13,27 @@ class ConvoOutputParser(AgentOutputParser):
return FORMAT_INSTRUCTIONS return FORMAT_INSTRUCTIONS
def parse(self, text: str) -> Union[AgentAction, AgentFinish]: def parse(self, text: str) -> Union[AgentAction, AgentFinish]:
cleaned_output = text.strip() try:
if "```json" in cleaned_output: cleaned_output = text.strip()
_, cleaned_output = cleaned_output.split("```json") if "```json" in cleaned_output:
if "```" in cleaned_output: _, cleaned_output = cleaned_output.split("```json")
cleaned_output, _ = cleaned_output.split("```") if "```" in cleaned_output:
if cleaned_output.startswith("```json"): cleaned_output, _ = cleaned_output.split("```")
cleaned_output = cleaned_output[len("```json") :] if cleaned_output.startswith("```json"):
if cleaned_output.startswith("```"): cleaned_output = cleaned_output[len("```json") :]
cleaned_output = cleaned_output[len("```") :] if cleaned_output.startswith("```"):
if cleaned_output.endswith("```"): cleaned_output = cleaned_output[len("```") :]
cleaned_output = cleaned_output[: -len("```")] if cleaned_output.endswith("```"):
cleaned_output = cleaned_output.strip() cleaned_output = cleaned_output[: -len("```")]
response = json.loads(cleaned_output) cleaned_output = cleaned_output.strip()
action, action_input = response["action"], response["action_input"] response = json.loads(cleaned_output)
if action == "Final Answer": action, action_input = response["action"], response["action_input"]
return AgentFinish({"output": action_input}, text) if action == "Final Answer":
else: return AgentFinish({"output": action_input}, text)
return AgentAction(action, action_input, text) else:
return AgentAction(action, action_input, text)
except Exception as e:
raise OutputParserException(f"Could not parse LLM output: {text}") from e
@property @property
def _type(self) -> str: def _type(self) -> str:

2
langchain/schema.py
View File

@ -360,7 +360,7 @@ class BaseOutputParser(BaseModel, ABC, Generic[T]):
return output_parser_dict return output_parser_dict
class OutputParserException(Exception): class OutputParserException(ValueError):
"""Exception that output parsers should raise to signify a parsing error. """Exception that output parsers should raise to signify a parsing error.
This exists to differentiate parsing errors from other code or execution errors This exists to differentiate parsing errors from other code or execution errors