deer-flow/backend/tests/test_checkpointer_none_fix.py
Daoyuan Li c143c0415b
fix(config): Make the sync checkpointer honor the unified database config (#3994)
* Make the sync checkpointer honor the unified database config

The sync checkpointer factory (`get_checkpointer` and `checkpointer_context`)
read only the legacy `checkpointer:` config section and fell back to
`InMemorySaver` when it was absent — it never consulted `database:`. The async
`make_checkpointer` factory and both sync/async Store providers already resolve
the unified `database:` section (legacy `checkpointer:` takes precedence,
otherwise `database:` drives the backend), so the sync checkpointer was the
lone outlier.

Consequence: with `database: {backend: sqlite|postgres}` and no legacy
`checkpointer:` section, the sync checkpointer silently returned `InMemorySaver`
while the Store — same process, same config — correctly persisted to
sqlite/postgres. Embedded callers (`DeerFlowClient`) and the TUI hit this: e.g.
the TUI writes `threads_meta` rows to sqlite (thread appears in the Web UI) but
its checkpoints went to memory and were lost on exit. This also contradicts
backend/AGENTS.md ("the unified `database` section selects the Gateway's
LangGraph checkpointer, LangGraph Store, and DeerFlow SQL repositories").

Mirror the sync Store provider: add `_resolve_checkpointer_config` /
`_get_checkpointer_config` (legacy precedence, else translate `database:` into
a CheckpointerConfig) and route both the singleton and the context manager
through them. The Gateway is unaffected — it uses the async path.

Adds a TestCheckpointerDatabaseConfig suite mirroring the Store's database
tests (singleton + context-manager honor `database:`, legacy precedence,
explicit-memory, missing-config fallback). The two `uses_database_config`
tests fail (return InMemorySaver) before the fix and pass after.

* Handle database=None in sync checkpointer resolution

The unified-config change made `checkpointer_context` / `get_checkpointer`
consult `app_config.database` when no legacy `checkpointer:` section is set.
`AppConfig.database` is always a `DatabaseConfig` in production, but the
existing regression test for issue #1016
(`test_checkpointer_none_fix.py::test_sync_checkpointer_context_returns_in_memory_saver_when_not_configured`)
mocks the app config with `database` left unset, exercising a `database=None`
path that now raised `ValueError: Unknown database backend`.

Mirror the async `make_checkpointer` factory, which already tolerates
`database=None` (falls back to memory), by treating a `None` database as the
memory backend in `_resolve_checkpointer_config`. Update the sync test to set
`mock_config.database = None`, matching its async sibling in the same file.

* Address review: mirror None-guard in store resolver, add sqlite coverage
2026-07-12 08:15:32 +08:00

57 lines
2.6 KiB
Python

"""Test for issue #1016: checkpointer should not return None."""
from unittest.mock import MagicMock, patch
import pytest
from langgraph.checkpoint.memory import InMemorySaver
class TestCheckpointerNoneFix:
"""Tests that checkpointer context managers return InMemorySaver instead of None."""
@pytest.mark.anyio
async def test_async_make_checkpointer_returns_in_memory_saver_when_not_configured(self):
"""make_checkpointer should return InMemorySaver when config.checkpointer is None."""
from deerflow.runtime.checkpointer.async_provider import make_checkpointer
# Mock get_app_config to return a config with checkpointer=None and database=None
mock_config = MagicMock()
mock_config.checkpointer = None
mock_config.database = None
with patch("deerflow.runtime.checkpointer.async_provider.get_app_config", return_value=mock_config):
async with make_checkpointer() as checkpointer:
# Should return InMemorySaver, not None
assert checkpointer is not None
assert isinstance(checkpointer, InMemorySaver)
# Should be able to call alist() without AttributeError
# This is what LangGraph does and what was failing in issue #1016
result = []
async for item in checkpointer.alist(config={"configurable": {"thread_id": "test"}}):
result.append(item)
# Empty list is expected for a fresh checkpointer
assert result == []
def test_sync_checkpointer_context_returns_in_memory_saver_when_not_configured(self):
"""checkpointer_context should return InMemorySaver when config.checkpointer is None."""
from deerflow.runtime.checkpointer.provider import checkpointer_context
# Mock get_app_config to return a config with checkpointer=None and database=None
mock_config = MagicMock()
mock_config.checkpointer = None
mock_config.database = None
with patch("deerflow.runtime.checkpointer.provider.get_app_config", return_value=mock_config):
with checkpointer_context() as checkpointer:
# Should return InMemorySaver, not None
assert checkpointer is not None
assert isinstance(checkpointer, InMemorySaver)
# Should be able to call list() without AttributeError
result = list(checkpointer.list(config={"configurable": {"thread_id": "test"}}))
# Empty list is expected for a fresh checkpointer
assert result == []