Fix transactional_db when requested via getfixturevalue

docs/changelog.rst

@@ -9,6 +9,14 @@ Compatibility
 
 * Official Django 6.1 support.
 
+Bugfixes
+^^^^^^^^
+
+* Fixed ``db`` / ``transactional_db`` (and related database fixtures) requested
+  via ``request.getfixturevalue()``, including indirect parametrization, always
+  using ``django.test.TestCase`` without transaction support
+  (`#1157 <https://github.com/pytest-dev/pytest-django/issues/1157>`__).
+
 v4.14.0 (2026-08-10)
 --------------------
 

pytest_django/fixtures.py

@@ -170,6 +170,7 @@ def django_db_setup(  # noqa: PLR0917
     django_db_modify_db_settings: None,  # noqa: ARG001
 ) -> Generator[None]:
     """Top level fixture to ensure test databases are available"""
+    from django.db import DEFAULT_DB_ALIAS
     from django.test.utils import setup_databases, teardown_databases
 
     setup_databases_args = {}
@@ -181,6 +182,11 @@ def django_db_setup(  # noqa: PLR0917
         setup_databases_args["keepdb"] = True
 
     aliases, serialized_aliases = _get_databases_for_setup(request.session.items)
+    if not aliases:
+        # This fixture is only requested when a test needs the database. Tests
+        # that obtain db fixtures via getfixturevalue() are invisible at
+        # collection time, so fall back to the default alias.
+        aliases = {DEFAULT_DB_ALIAS}
 
     with django_db_blocker.unblock():
         db_cfg = setup_databases(
@@ -203,6 +209,24 @@ def django_db_setup(  # noqa: PLR0917
                 )
 
 
+def _requested_fixture_names(request: pytest.FixtureRequest) -> set[str]:
+    """Return fixture names for this test, including those currently being set up.
+
+    ``request.fixturenames`` is the collected fixture closure plus fixtures that
+    have already finished. A fixture requested via ``request.getfixturevalue()``
+    is only recorded after it finishes, so ``_django_db_helper`` (a dependency
+    of ``db`` / ``transactional_db``) would otherwise miss it.
+    """
+    names = set(request.fixturenames)
+    current: pytest.FixtureRequest | None = request
+    while current is not None:
+        fixturename = current.fixturename
+        if fixturename is not None:
+            names.add(fixturename)
+        current = getattr(current, "_parent_request", None)
+    return names
+
+
 @pytest.fixture
 def _django_db_helper(
     request: pytest.FixtureRequest,
@@ -233,14 +257,13 @@ def _django_db_helper(
             available_apps,
         ) = False, False, None, False, None
 
+    requested = _requested_fixture_names(request)
+    reset_sequences = reset_sequences or ("django_db_reset_sequences" in requested)
+    serialized_rollback = serialized_rollback or ("django_db_serialized_rollback" in requested)
     transactional = (
         transactional
         or reset_sequences
-        or ("transactional_db" in request.fixturenames or "live_server" in request.fixturenames)
-    )
-    reset_sequences = reset_sequences or ("django_db_reset_sequences" in request.fixturenames)
-    serialized_rollback = serialized_rollback or (
-        "django_db_serialized_rollback" in request.fixturenames
+        or ("transactional_db" in requested or "live_server" in requested)
     )
 
     with django_db_blocker.unblock():

tests/test_database.py

@@ -101,6 +101,20 @@ def test_transactions_enabled_via_reset_seq(
 
         assert not connection.in_atomic_block
 
+    def test_transactions_match_dynamic_db_fixture(
+        self,
+        all_dbs: None,  # noqa: ARG002
+        request: pytest.FixtureRequest,
+    ) -> None:
+        if not connection.features.supports_transactions:
+            pytest.skip("transactions required for this test")
+
+        fixture_name = request.node.callspec.params["all_dbs"]
+        if fixture_name in {"transactional_db", "django_db_reset_sequences"}:
+            assert not connection.in_atomic_block
+        else:
+            assert connection.in_atomic_block
+
     def test_django_db_reset_sequences_fixture(
         self,
         db: None,  # noqa: ARG002
@@ -213,6 +227,26 @@ def test_durable_transactions(self, all_dbs: None) -> None:  # noqa: ARG002
         assert Item.objects.get() == item
 
 
+@pytest.mark.parametrize("db_access", ["db", "transactional_db"], indirect=True)
+class TestIndirectDbParametrization:
+    """Indirect parametrization of db vs transactional_db (issue #1157)."""
+
+    @pytest.fixture
+    def db_access(self, request: pytest.FixtureRequest) -> str:
+        fixture_name: str = request.param
+        request.getfixturevalue(fixture_name)
+        return fixture_name
+
+    def test_atomic_block_matches_fixture(self, db_access: str) -> None:
+        if not connection.features.supports_transactions:
+            pytest.skip("transactions required for this test")
+
+        if db_access == "transactional_db":
+            assert not connection.in_atomic_block
+        else:
+            assert connection.in_atomic_block
+
+
 class TestDatabaseFixturesAllOrder:
     @pytest.fixture
     def fixture_with_db(self, db: None) -> None:  # noqa: ARG002