fix: 'Could not refresh instance' when using EventSession (#341)

docs/module/fixtures.md

@@ -65,6 +65,13 @@ Both functions return a `dict[str, list[...]]` mapping each fixture name to the
 
 A fixture with no `contexts` defined takes `Context.BASE` by default.
 
+`Context.BASE` fixtures are always included alongside whatever context you load or list — there's no way to load a non-base context in isolation:
+
+```python
+# also loads any Context.BASE fixtures, even though only TESTING is requested
+await load_fixtures_by_context(session, fixtures, Context.TESTING)
+```
+
 ### Custom contexts
 
 Plain strings and any `Enum` subclass are accepted wherever a `Context` enum is expected.
@@ -80,6 +87,7 @@ class AppContext(str, Enum):
 def staging_data():
     return [Config(key="feature_x", enabled=True)]
 
+# loads staging_data plus any Context.BASE fixtures
 await load_fixtures_by_context(session, fixtures, AppContext.STAGING)
 ```
 
@@ -108,8 +116,8 @@ def users():
 def users():
     return [User(id=2, username="tester")]
 
-# loads both admin and tester
-await load_fixtures_by_context(session, fixtures, Context.BASE, Context.TESTING)
+# loads both admin and tester (Context.BASE is included automatically)
+await load_fixtures_by_context(session, fixtures, Context.TESTING)
 ```
 
 Registering two variants with overlapping context sets raises `ValueError`.

src/fastapi_toolsets/cli/commands/fixtures.py

@@ -24,7 +24,7 @@ logger = get_logger()
 def list_fixtures(
     ctx: typer.Context,
     context: Annotated[
-        Context | None,
+        str | None,
         typer.Option(
             "--context",
             "-c",
@@ -56,7 +56,7 @@ def list_fixtures(
 async def load(
     ctx: typer.Context,
     contexts: Annotated[
-        list[Context] | None,
+        list[str] | None,
         typer.Argument(help="Contexts to load."),
     ] = None,
     strategy: Annotated[
@@ -76,7 +76,7 @@ async def load(
     registry = get_fixtures_registry()
     db_context = get_db_context()
 
-    context_list = contexts or [Context.BASE]
+    context_list = contexts or [Context.BASE.value]
 
     ordered = registry.resolve_context_dependencies(*context_list)
 

src/fastapi_toolsets/db/watch.py

@@ -57,10 +57,18 @@ async def wait_for_row_change(
         )
         ```
     """
+    bind = getattr(session, "bind", None)
+    if bind is None:
+        raise TypeError(
+            "wait_for_row_change requires a session bound to an engine "
+            "(session.bind is None)"
+        )
+    watcher = AsyncSession(bind=bind)
+    try:
 
         async def _reload() -> _M | None:
-        await session.rollback()
-        return await session.get(model, pk_value, populate_existing=True)
+            await watcher.rollback()
+            return await watcher.get(model, pk_value, populate_existing=True)
 
         instance = await _reload()
         if instance is None:
@@ -87,8 +95,12 @@ async def wait_for_row_change(
             instance = await _reload()
 
             if instance is None:
-            raise NotFoundError(f"{model.__name__} with pk={pk_value!r} was deleted")
+                raise NotFoundError(
+                    f"{model.__name__} with pk={pk_value!r} was deleted"
+                )
 
             current = {col: getattr(instance, col) for col in watch_cols}
             if current != initial:
                 return instance
+    finally:
+        await watcher.close()

src/fastapi_toolsets/fixtures/registry.py

@@ -17,6 +17,11 @@ def _normalize_contexts(
     return [c.value if isinstance(c, Enum) else c for c in contexts]
 
 
+def _context_filter_values(contexts: tuple[str | Enum, ...]) -> set[str]:
+    """Normalize *contexts* for filtering, always including Context.BASE."""
+    return set(_normalize_contexts(contexts)) | {Context.BASE.value}
+
+
 @dataclass
 class Fixture:
     """A fixture definition with metadata."""
@@ -67,8 +72,6 @@ class FixtureRegistry:
         @fixtures.register(contexts=[Context.TESTING])
         def users():
             return [User(id=2, username="tester")]
-        # load_fixtures_by_context(..., Context.BASE, Context.TESTING)
-        # → loads both User(admin) and User(tester) under the "users" name
         ```
     """
 
@@ -200,8 +203,9 @@ class FixtureRegistry:
         Args:
             name: Fixture name.
             *contexts: If given, only return variants whose context set
-                intersects with these values.  Both :class:`Context` enum
-                values and plain strings are accepted.
+                intersects with these values (:class:`Context.BASE` variants
+                are always included).  Both :class:`Context` enum values and
+                plain strings are accepted.
 
         Returns:
             List of matching :class:`Fixture` objects (may be empty when a
@@ -215,7 +219,7 @@ class FixtureRegistry:
         variants = self._fixtures[name]
         if not contexts:
             return list(variants)
-        context_values = set(_normalize_contexts(contexts))
+        context_values = _context_filter_values(contexts)
         return [v for v in variants if set(v.contexts) & context_values]
 
     def get_load_variants(self, name: str, *contexts: str | Enum) -> list[Fixture]:
@@ -297,7 +301,7 @@ class FixtureRegistry:
 
     def get_by_context(self, *contexts: str | Enum) -> list[Fixture]:
         """Get fixtures for specific contexts."""
-        context_values = set(_normalize_contexts(contexts))
+        context_values = _context_filter_values(contexts)
         return [
             f
             for variants in self._fixtures.values()

src/fastapi_toolsets/fixtures/utils.py

@@ -383,8 +383,8 @@ async def load_fixtures_by_context(
     Args:
         session: Database session
         registry: Fixture registry
-        *contexts: Contexts to load (e.g., ``Context.BASE``, ``Context.TESTING``,
-            or plain strings for custom contexts)
+        *contexts: Contexts to load (e.g., ``Context.TESTING``, or plain
+            strings for custom contexts)
         strategy: How to handle existing records
 
     Returns:

src/fastapi_toolsets/models/watched.py

@@ -204,6 +204,11 @@ async def _invoke_callback(
         await result
 
 
+async def _reload_if_present(session: AsyncSession, obj: Any, state: Any) -> None:
+    """Re-populate *obj* from the DB if its row still exists."""
+    await session.get(type(obj), state.key[1], populate_existing=True)
+
+
 class EventSession(AsyncSession):
     """AsyncSession subclass that dispatches lifecycle callbacks after commit."""
 
@@ -253,7 +258,7 @@ class EventSession(AsyncSession):
                     state is None or state.detached or state.transient
                 ):  # pragma: no cover
                     continue
-                await self.refresh(obj)
+                await _reload_if_present(self, obj, state)
                 for handler in _get_handlers(type(obj), ModelEvent.CREATE):
                     await _invoke_callback(handler, obj, ModelEvent.CREATE, None)
             except Exception as exc:
@@ -277,7 +282,7 @@ class EventSession(AsyncSession):
                     state is None or state.detached or state.transient
                 ):  # pragma: no cover
                     continue
-                await self.refresh(obj)
+                await _reload_if_present(self, obj, state)
                 for handler in _get_handlers(type(obj), ModelEvent.UPDATE):
                     await _invoke_callback(handler, obj, ModelEvent.UPDATE, changes)
             except Exception as exc:

tests/test_cli.py

@@ -277,6 +277,10 @@ class TestFixturesCli:
             '@registry.register(depends_on=["roles"], contexts=[Context.TESTING])\n'
             "def users():\n"
             '    return [{"id": 1, "name": "alice", "role_id": 1}]\n'
+            "\n"
+            '@registry.register(contexts=["staging"])\n'
+            "def staging_only():\n"
+            '    return [{"id": 3, "name": "staging-user"}]\n'
         )
 
         # Create db module
@@ -316,7 +320,7 @@ class TestFixturesCli:
         assert result.exit_code == 0
         assert "roles" in result.output
         assert "users" in result.output
-        assert "Total: 2 fixture(s)" in result.output
+        assert "Total: 3 fixture(s)" in result.output
 
     def test_fixtures_list_with_context(self, cli_env):
         """fixtures list --context filters by context."""
@@ -338,6 +342,27 @@ class TestFixturesCli:
         assert "roles" in result.output
         assert "[Dry run - no changes made]" in result.output
 
+    def test_fixtures_list_with_custom_context(self, cli_env):
+        """fixtures list --context accepts contexts outside the Context enum, and
+        always includes base fixtures alongside the requested context."""
+        tmp_path, cli = cli_env
+        result = runner.invoke(cli, ["fixtures", "list", "--context", "staging"])
+
+        assert result.exit_code == 0
+        assert "staging_only" in result.output
+        assert "roles" in result.output
+        assert "Total: 2 fixture(s)" in result.output
+
+    def test_fixtures_load_custom_context_dry_run(self, cli_env):
+        """fixtures load accepts a custom context argument outside the Context enum,
+        and always loads base fixtures alongside it."""
+        tmp_path, cli = cli_env
+        result = runner.invoke(cli, ["fixtures", "load", "staging", "--dry-run"])
+
+        assert result.exit_code == 0
+        assert "staging_only" in result.output
+        assert "roles" in result.output
+
     def test_fixtures_load_invalid_strategy(self, cli_env):
         """fixtures load with invalid strategy shows error."""
         tmp_path, cli = cli_env

tests/test_db.py

@@ -689,6 +689,13 @@ class TestWaitForRowChange:
         with pytest.raises(NotFoundError, match="not found"):
             await wait_for_row_change(db_session, Role, fake_id, interval=0.05)
 
+    @pytest.mark.anyio
+    async def test_unbound_session_raises_type_error(self):
+        """Raises TypeError when the session has no bind to open a watcher on."""
+        unbound = AsyncSession()
+        with pytest.raises(TypeError, match="requires a session bound to an engine"):
+            await wait_for_row_change(unbound, Role, uuid.uuid4())
+
     @pytest.mark.anyio
     async def test_timeout_raises(self, db_session: AsyncSession):
         """Raises TimeoutError when no change is detected within timeout."""
@@ -781,6 +788,43 @@ class TestWaitForRowChange:
             await wait_for_row_change(db_session, Role, role.id, interval=0.05)
         await delete_task
 
+    @pytest.mark.anyio
+    async def test_does_not_disturb_ambient_transaction(
+        self, db_session: AsyncSession, engine
+    ):
+        """A read-only ambient transaction around the call survives untouched."""
+        role = Role(name="ambient_role")
+        db_session.add(role)
+        await db_session.commit()
+
+        async def update_later():
+            await asyncio.sleep(0.15)
+            factory = async_sessionmaker(engine, expire_on_commit=False)
+            async with factory() as other:
+                r = await other.get(Role, role.id)
+                assert r is not None
+                r.name = "ambient_updated"
+                await other.commit()
+
+        update_task = asyncio.create_task(update_later())
+        async with transaction(db_session):
+            # A read before the watch, establishing an ambient transaction
+            # that must remain usable once wait_for_row_change returns.
+            await db_session.get(Role, role.id)
+            result = await wait_for_row_change(
+                db_session, Role, role.id, interval=0.05, timeout=2.0
+            )
+            await update_task
+            assert result.name == "ambient_updated"
+            # The ambient transaction must still be open and usable here.
+            assert db_session.in_transaction()
+            other_role = Role(name="added_within_ambient_tx")
+            db_session.add(other_role)
+
+        # transaction() committed cleanly on exit; the write above landed.
+        check = await db_session.get(Role, other_role.id)
+        assert check is not None
+
 
 class TestCreateDatabase:
     """Tests for create_database."""

tests/test_fixtures.py

@@ -266,7 +266,34 @@ class TestFixtureRegistry:
 
         testing_fixtures = registry.get_by_context(Context.TESTING)
         names = {f.name for f in testing_fixtures}
-        assert names == {"test_data"}
+        assert names == {"test_data", "base_data"}
+
+    def test_get_by_context_always_includes_base(self):
+        """Context.BASE fixtures load even for a fully custom context."""
+        registry = FixtureRegistry()
+
+        @registry.register(contexts=[Context.BASE])
+        def base_data():
+            return []
+
+        @registry.register(contexts=["staging"])
+        def staging_data():
+            return []
+
+        names = {f.name for f in registry.get_by_context("staging")}
+        assert names == {"staging_data", "base_data"}
+
+    def test_get_load_variants_falls_back_to_all_when_context_has_no_match(self):
+        """get_load_variants returns every variant if none match the requested
+        context (and none are Context.BASE either)."""
+        registry = FixtureRegistry()
+
+        @registry.register(contexts=["staging"])
+        def env_data():
+            return []
+
+        variants = registry.get_load_variants("env_data", "production")
+        assert [v.contexts for v in variants] == [["staging"]]
 
 
 class TestIncludeRegistry:

tests/test_models.py

@@ -21,12 +21,12 @@ from fastapi_toolsets.models import (
     listens_for,
 )
 from fastapi_toolsets.models.watched import (
-    EventSession,
     _EVENT_HANDLERS,
     _SESSION_CREATES,
     _SESSION_DELETES,
     _SESSION_UPDATES,
     _WATCHED_MODELS,
+    EventSession,
     _after_flush,
     _after_rollback,
     _get_watched_fields,
@@ -1001,6 +1001,57 @@ class TestEventCallbacks:
 
         assert _test_events == []
 
+    @pytest.mark.anyio
+    async def test_create_survives_row_deleted_before_reload(self, mixin_session):
+        """A row deleted by another transaction right after commit still fires CREATE."""
+        keep = WatchedModel(status="active", other="x")
+        doomed = WatchedModel(status="active", other="x")
+        mixin_session.add_all([keep, doomed])
+        await mixin_session.flush()
+        doomed_id = doomed.id
+
+        raced = {"done": False}
+
+        async def kill_doomed_row_once():
+            if raced["done"]:
+                return
+            raced["done"] = True
+            engine = create_async_engine(DATABASE_URL, echo=False)
+            async with async_sessionmaker(engine)() as other:
+                row = await other.get(WatchedModel, doomed_id)
+                await other.delete(row)
+                await other.commit()
+            await engine.dispose()
+
+        real_get = mixin_session.get
+        real_refresh = mixin_session.refresh
+
+        def _matches_doomed(pk):
+            return pk == doomed_id or (isinstance(pk, tuple) and pk[0] == doomed_id)
+
+        async def racing_get(model, pk, *args, **kwargs):
+            if _matches_doomed(pk):
+                await kill_doomed_row_once()
+            return await real_get(model, pk, *args, **kwargs)
+
+        async def racing_refresh(obj, *args, **kwargs):
+            if getattr(obj, "id", None) == doomed_id:
+                await kill_doomed_row_once()
+            return await real_refresh(obj, *args, **kwargs)
+
+        # Patch both possible reload mechanisms (session.get / session.refresh)
+        # so this test still exercises the race regardless of which one
+        # EventSession.commit() uses internally to pick up server defaults.
+        mixin_session.get = racing_get
+        mixin_session.refresh = racing_refresh
+        with patch.object(_watched_module._logger, "error") as mock_error:
+            await mixin_session.commit()
+            mock_error.assert_not_called()
+
+        assert raced["done"]
+        created_ids = {e["obj_id"] for e in _test_events if e["event"] == "create"}
+        assert created_ids == {keep.id, doomed_id}
+
 
 class TestTransientObject:
     """Create + delete within the same transaction should fire no events."""