Support checking for db path absoluteness on Windows

airflow/settings.py

@@ -278,17 +278,30 @@ def remove(*args, **kwargs):
         pass
 
 
+def _is_sqlite_db_path_relative(sqla_conn_str: str) -> bool:
+    """Determine whether the database connection URI specifies a relative path."""
+    # Check for non-empty connection string:
+    if not sqla_conn_str:
+        return False
+    # Check for the right URI scheme:
+    if not sqla_conn_str.startswith("sqlite"):
+        return False
+    # In-memory is not useful for production, but useful for writing tests against Airflow for extensions
+    if sqla_conn_str == "sqlite://":
+        return False
+    # Check for absolute path:
+    if sqla_conn_str.startswith(abs_prefix := "sqlite:///") and os.path.isabs(
+        sqla_conn_str[len(abs_prefix) :]
+    ):
+        return False
+    return True
+
+
 def configure_orm(disable_connection_pool=False, pool_class=None):
     """Configure ORM using SQLAlchemy."""
     from airflow.utils.log.secrets_masker import mask_secret
 
-    if (
-        SQL_ALCHEMY_CONN
-        and SQL_ALCHEMY_CONN.startswith("sqlite")
-        and not SQL_ALCHEMY_CONN.startswith("sqlite:////")
-        # In memory is not useful for production, but useful for writing tests against Airflow for extensions
-        and SQL_ALCHEMY_CONN != "sqlite://"
-    ):
+    if _is_sqlite_db_path_relative(SQL_ALCHEMY_CONN):
         from airflow.exceptions import AirflowConfigException
 
         raise AirflowConfigException(

airflow/www/app.py

@@ -19,6 +19,7 @@
 
 import warnings
 from datetime import timedelta
+from os.path import isabs
 
 from flask import Flask
 from flask_appbuilder import SQLA
@@ -100,7 +101,7 @@ def create_app(config=None, testing=False):
     flask_app.config["REQUIRE_CONFIRMATION_DAG_CHANGE"] = require_confirmation_dag_change
 
     url = make_url(flask_app.config["SQLALCHEMY_DATABASE_URI"])
-    if url.drivername == "sqlite" and url.database and not url.database.startswith("/"):
+    if url.drivername == "sqlite" and url.database and not isabs(url.database):
         raise AirflowConfigException(
             f'Cannot use relative path: `{conf.get("database", "SQL_ALCHEMY_CONN")}` to connect to sqlite. '
             "Please use absolute path such as `sqlite:////tmp/airflow.db`."

tests/core/test_settings.py

@@ -230,14 +230,24 @@ def test_uses_updated_session_timeout_config_by_default(self):
         assert session_lifetime_config == default_timeout_minutes
 
 
+_local_db_path_error = pytest.raises(AirflowConfigException, match=r"Cannot use relative path:")
+
+
 @pytest.mark.parametrize(
     ["value", "expectation"],
     [
-        (
-            "sqlite:///./relative_path.db",
-            pytest.raises(AirflowConfigException, match=r"Cannot use relative path:"),
+        ("sqlite:///./relative_path.db", _local_db_path_error),
+        ("sqlite:///relative/path.db", _local_db_path_error),
+        pytest.param(
+            "sqlite:///C:/path/to/db",
+            _local_db_path_error,
+            marks=pytest.mark.skipif(sys.platform.startswith("win"), reason="Skip on Windows"),
+        ),
+        pytest.param(
+            r"sqlite:///C:\path\to\db",
+            _local_db_path_error,
+            marks=pytest.mark.skipif(sys.platform.startswith("win"), reason="Skip on Windows"),
         ),
-        # Should not raise an exception
         ("sqlite://", contextlib.nullcontext()),
     ],
 )