litellm/tests/integration/sdk/test_response_cache_sync_sdk.py
devin-ai-integration[bot] abd3af422d
fix(caching): never store or serve a chat completion with no choices (#44709)
* fix(caching): never store or serve a chat completion with no choices

A provider response with empty choices was written to the response cache and served on every identical request until the TTL ended, with no provider call in between. The cache now skips storing such a response and treats an already stored one as a miss, so the next request goes back to the provider and its answer replaces the entry.

* fix(caching): skip responses with no output on the Responses API and Anthropic Messages too

* fix(caching): skip streams and stored entries that carry no output

A chat or text completion stream whose chunks carried no choice is closed
by the stream wrapper with one empty choice of its own, so the assembled
response passed the choices check and was cached. The assembled stream is
now judged on its content: a stream with no text, tool call, or other
output in any choice is never stored, on the async and sync writers alike.
The Responses API stream writer and the Anthropic Messages stream writer
apply the same no-output check before storing.

A stored entry with no output read through the worker memory tier is now
evicted from that tier on the miss, so the next read reaches Redis where
the refill lands; the text completion and messages writers only write to
Redis, and the memory copy otherwise kept missing until its own TTL.

* test(integration): response cache cells for answers without output

Deterministic cells for the response cache on every unified endpoint,
streamed and not, through the OpenAI and Anthropic SDKs and raw httpx,
plus the sync SDK paths, stale entries, malformed answers, per-request
TTLs, cache delete, and chaos (Redis stopped or paused mid burst, a
worker killed, in-memory cache mode). The scripted upstream counts only
POSTs as deployment calls, since the proxy's boot-time GET /v1/models
discovery of a config deployment is not one.

* test(caching): pin the stored entry timestamp in the worker-copy test

* test(integration): drop the restating comments from the chaos cells

* test(integration): close the breaker on the first call after the Redis restart

---------

Co-authored-by: mateo-berri <277851410+mateo-berri@users.noreply.github.com>
2026-10-06 20:07:30 +00:00

125 lines
5.2 KiB
Python

"""The sync SDK paths of the response cache, which the proxy never reaches.
``litellm.completion`` and ``litellm.text_completion`` read and write the Redis cache in process. An upstream
answer with no choices is never stored, a stored entry whose choices were emptied is a miss, and the real answer
the refill brings back is the one served afterwards.
"""
from __future__ import annotations
import os
from collections.abc import Iterator
from typing import Final
import pytest
import litellm
from litellm.caching.caching import Cache
from litellm.types.caching import LiteLLMCacheType
from litellm.types.utils import ModelResponse, TextCompletionResponse
from tests.integration.caching.response_cache_case import (
CHAT,
CHAT_MODEL,
PROVIDER_KEY,
TEXT,
TEXT_MODEL,
Upstream,
await_entry,
emptied,
flip_entry_to_empty,
json_response,
prompt,
redis_store,
rescript,
scripted_in_process,
)
@pytest.fixture
def sdk_cache(monkeypatch: pytest.MonkeyPatch) -> Iterator[Cache]:
cache: Final = Cache(type=LiteLLMCacheType.REDIS, host=os.environ["REDIS_HOST"], port=os.environ["REDIS_PORT"])
monkeypatch.setattr(litellm, "cache", cache)
yield cache
monkeypatch.setattr(litellm, "cache", None)
def _completion(api_base: str, text: str) -> ModelResponse:
response: Final = litellm.completion(
model=CHAT_MODEL, messages=[{"role": "user", "content": text}], api_base=api_base, api_key=PROVIDER_KEY
)
assert isinstance(response, ModelResponse), type(response)
return response
def _text_completion(api_base: str, text: str) -> TextCompletionResponse:
response: Final = litellm.text_completion(model=TEXT_MODEL, prompt=text, api_base=api_base, api_key=PROVIDER_KEY)
assert isinstance(response, TextCompletionResponse), type(response)
return response
def _content(response: ModelResponse) -> object:
assert len(response.choices) == 1, response.model_dump_json()
return response.choices[0].model_dump()["message"]["content"]
def _text(response: TextCompletionResponse) -> object:
assert len(response.choices) == 1, response.model_dump_json()
return response.choices[0].model_dump()["text"]
@pytest.mark.usefixtures("sdk_cache")
def test_sync_completion_with_empty_choices_reaches_upstream_again_and_the_real_answer_is_cached() -> None:
upstream: Final = Upstream()
text: Final = prompt()
with scripted_in_process(json_response(emptied(CHAT, "choices"))) as handle:
empty: Final = _completion(handle.api_base(), text)
assert empty.choices == [], empty.model_dump_json()
assert upstream.calls(handle.scenario_id) == 1
rescript(handle, json_response(CHAT))
refilled: Final = _completion(handle.api_base(), text)
assert _content(refilled) == "scripted", f"the empty answer was served: {refilled.model_dump_json()}"
assert refilled.id != empty.id
assert upstream.calls(handle.scenario_id) == 2
with redis_store() as store:
await_entry(store, refilled.id)
hit: Final = _completion(handle.api_base(), text)
assert hit.id == refilled.id, hit.model_dump_json()
assert _content(hit) == "scripted"
assert upstream.calls(handle.scenario_id) == 2
@pytest.mark.usefixtures("sdk_cache")
def test_sync_completion_treats_a_stale_entry_with_empty_choices_as_a_miss() -> None:
upstream: Final = Upstream()
text: Final = prompt()
with scripted_in_process(json_response(CHAT)) as handle, redis_store() as store:
first: Final = _completion(handle.api_base(), text)
assert _content(first) == "scripted", first.model_dump_json()
stale_id: Final = flip_entry_to_empty(store, await_entry(store, first.id), "choices")
refilled: Final = _completion(handle.api_base(), text)
assert refilled.id != stale_id, f"the stale entry was served: {refilled.model_dump_json()}"
assert _content(refilled) == "scripted" and refilled.id != first.id, refilled.model_dump_json()
assert upstream.calls(handle.scenario_id) == 2
await_entry(store, refilled.id)
hit: Final = _completion(handle.api_base(), text)
assert hit.id == refilled.id, hit.model_dump_json()
assert upstream.calls(handle.scenario_id) == 2
@pytest.mark.usefixtures("sdk_cache")
def test_sync_text_completion_with_empty_choices_reaches_upstream_again() -> None:
upstream: Final = Upstream()
text: Final = prompt()
with scripted_in_process(json_response(emptied(TEXT, "choices"))) as handle:
empty: Final = _text_completion(handle.api_base(), text)
assert empty.choices == [], empty.model_dump_json()
assert upstream.calls(handle.scenario_id) == 1
rescript(handle, json_response(TEXT))
refilled: Final = _text_completion(handle.api_base(), text)
assert _text(refilled) == "scripted", f"the empty answer was served: {refilled.model_dump_json()}"
assert upstream.calls(handle.scenario_id) == 2
with redis_store() as store:
await_entry(store, refilled.id)
hit: Final = _text_completion(handle.api_base(), text)
assert hit.id == refilled.id, hit.model_dump_json()
assert upstream.calls(handle.scenario_id) == 2