fix: format, lint, and update tests for namespace delegation

- Run ruff format on all changed files
- Fix F821 forward reference in _namespace_conn return type
- Update test_local_namespace_operations to verify operations succeed
  instead of expecting NotImplementedError (namespace ops now work on
  LanceDBConnection via directory namespace delegation)
- Remove test_local_create_namespace_not_supported and
  test_local_drop_namespace_not_supported (no longer applicable)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

python/python/lancedb/__init__.py

@@ -232,7 +232,7 @@ def _apply_worker_overrides(props: dict[str, str]) -> dict[str, str]:
     result = dict(props)
     for key in worker_keys:
         value = result.pop(key)
-        real_key = key[len(WORKER_PROPERTY_PREFIX):]
+        real_key = key[len(WORKER_PROPERTY_PREFIX) :]
         result[real_key] = value
     return result
 

python/python/lancedb/db.py

@@ -540,9 +540,7 @@ class DBConnection(EnforceOverrides):
         str
             Serialized representation of this connection.
         """
-        raise NotImplementedError(
-            "serialize is not supported for this connection type"
-        )
+        raise NotImplementedError("serialize is not supported for this connection type")
 
 
 class LanceDBConnection(DBConnection):
@@ -674,14 +672,16 @@ class LanceDBConnection(DBConnection):
         import json
 
         rci = self.read_consistency_interval
-        return json.dumps({
-            "connection_type": "local",
-            "uri": self.uri,
-            "storage_options": self.storage_options,
-            "read_consistency_interval_seconds": (
-                rci.total_seconds() if rci else None
-            ),
-        })
+        return json.dumps(
+            {
+                "connection_type": "local",
+                "uri": self.uri,
+                "storage_options": self.storage_options,
+                "read_consistency_interval_seconds": (
+                    rci.total_seconds() if rci else None
+                ),
+            }
+        )
 
     async def _async_get_table_names(self, start_after: Optional[str], limit: int):
         conn = AsyncConnection(await lancedb_connect(self.uri))
@@ -918,7 +918,7 @@ class LanceDBConnection(DBConnection):
         )
         return tbl
 
-    def _namespace_conn(self) -> "LanceNamespaceDBConnection":
+    def _namespace_conn(self) -> DBConnection:
         """Return a LanceNamespaceDBConnection backed by this connection's
         directory namespace.  Used to delegate child-namespace operations."""
         from lancedb.namespace import LanceNamespaceDBConnection
@@ -1122,9 +1122,7 @@ class LanceDBConnection(DBConnection):
             The namespace client for this connection.
         """
         if self._cached_namespace_client is None:
-            self._cached_namespace_client = LOOP.run(
-                self._conn.namespace_client()
-            )
+            self._cached_namespace_client = LOOP.run(self._conn.namespace_client())
         return self._cached_namespace_client
 
     @deprecation.deprecated(

python/python/lancedb/namespace.py

@@ -427,18 +427,20 @@ class LanceNamespaceDBConnection(DBConnection):
     def serialize(self) -> str:
         import json
 
-        return json.dumps({
-            "connection_type": "namespace",
-            "namespace_client_impl": self._namespace_client_impl,
-            "namespace_client_properties": self._namespace_client_properties,
-            "pushdown_operations": sorted(self._pushdown_operations),
-            "storage_options": self.storage_options or None,
-            "read_consistency_interval_seconds": (
-                self.read_consistency_interval.total_seconds()
-                if self.read_consistency_interval
-                else None
-            ),
-        })
+        return json.dumps(
+            {
+                "connection_type": "namespace",
+                "namespace_client_impl": self._namespace_client_impl,
+                "namespace_client_properties": self._namespace_client_properties,
+                "pushdown_operations": sorted(self._pushdown_operations),
+                "storage_options": self.storage_options or None,
+                "read_consistency_interval_seconds": (
+                    self.read_consistency_interval.total_seconds()
+                    if self.read_consistency_interval
+                    else None
+                ),
+            }
+        )
 
     @override
     def table_names(

python/python/tests/test_db.py

@@ -897,42 +897,22 @@ def test_bypass_vector_index_sync(tmp_db: lancedb.DBConnection):
 
 
 def test_local_namespace_operations(tmp_path):
-    """Test that local mode namespace operations behave as expected."""
-    # Create a local database connection
+    """Test that local mode namespace operations work via directory namespace."""
     db = lancedb.connect(tmp_path)
 
-    # Test list_namespaces returns empty list for root namespace
-    namespaces = db.list_namespaces().namespaces
-    assert namespaces == []
+    # Root namespace starts empty
+    assert db.list_namespaces().namespaces == []
 
-    # Test list_namespaces with non-empty namespace raises NotImplementedError
-    with pytest.raises(
-        NotImplementedError,
-        match="Namespace operations are not supported for listing database",
-    ):
-        db.list_namespaces(namespace_path=["test"])
+    # Create and list child namespace
+    db.create_namespace(["child"])
+    assert "child" in db.list_namespaces().namespaces
 
+    # List namespaces under child
+    assert db.list_namespaces(namespace_path=["child"]).namespaces == []
 
-def test_local_create_namespace_not_supported(tmp_path):
-    """Test that create_namespace is not supported in local mode."""
-    db = lancedb.connect(tmp_path)
-
-    with pytest.raises(
-        NotImplementedError,
-        match="Namespace operations are not supported for listing database",
-    ):
-        db.create_namespace(["test_namespace"])
-
-
-def test_local_drop_namespace_not_supported(tmp_path):
-    """Test that drop_namespace is not supported in local mode."""
-    db = lancedb.connect(tmp_path)
-
-    with pytest.raises(
-        NotImplementedError,
-        match="Namespace operations are not supported for listing database",
-    ):
-        db.drop_namespace(["test_namespace"])
+    # Drop namespace
+    db.drop_namespace(["child"])
+    assert db.list_namespaces().namespaces == []
 
 
 def test_clone_table_latest_version(tmp_path):