github/langchain
1
0
Fork 0
mirror of https://github.com/hwchase17/langchain.git synced 2025-06-25 08:03:39 +00:00
Code Issues Packages Projects Releases Wiki Activity

core: Fix IndexError when trim_messages invoked with empty list (#26896)

Browse Source 
This prevents `trim_messages` from raising an `IndexError` when invoked
with `include_system=True`, `strategy="last"`, and an empty message
list.

Fixes #26895

Dependencies: none
This commit is contained in:
Julius Stopforth 2024-09-26 17:29:58 +02:00 committed by GitHub
parent 7091a1a798
commit 121e79b1f0
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
2 changed files with 16 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
libs/core/langchain_core/messages/utils.py
View File

@ -819,6 +819,7 @@ def trim_messages(
def list_token_counter(messages: Sequence[BaseMessage]) -> int: def list_token_counter(messages: Sequence[BaseMessage]) -> int:
return sum(token_counter(msg) for msg in messages) # type: ignore[arg-type, misc] return sum(token_counter(msg) for msg in messages) # type: ignore[arg-type, misc]
else: else:
list_token_counter = token_counter # type: ignore[assignment] list_token_counter = token_counter # type: ignore[assignment]
else: else:
@ -956,6 +957,8 @@ def _last_max_tokens(
] = None, ] = None,
) -> list[BaseMessage]: ) -> list[BaseMessage]:
messages = list(messages) messages = list(messages)
if len(messages) == 0:
return []
if end_on: if end_on:
while messages and not _is_message_type(messages[-1], end_on): while messages and not _is_message_type(messages[-1], end_on):
messages.pop() messages.pop()

13
libs/core/tests/unit_tests/messages/test_utils.py
View File

@ -332,6 +332,19 @@ def test_trim_messages_allow_partial_text_splitter() -> None:
assert _MESSAGES_TO_TRIM == _MESSAGES_TO_TRIM_COPY assert _MESSAGES_TO_TRIM == _MESSAGES_TO_TRIM_COPY
def test_trim_messages_include_system_strategy_last_empty_messages() -> None:
expected: list[BaseMessage] = []
actual = trim_messages(
max_tokens=10,
token_counter=dummy_token_counter,
strategy="last",
include_system=True,
).invoke([])
assert actual == expected
def test_trim_messages_invoke() -> None: def test_trim_messages_invoke() -> None:
actual = trim_messages(max_tokens=10, token_counter=dummy_token_counter).invoke( actual = trim_messages(max_tokens=10, token_counter=dummy_token_counter).invoke(
_MESSAGES_TO_TRIM _MESSAGES_TO_TRIM