Pin returns_native_bytes on the dqlite dialect

dqlitedbapi returns native Python bytes for BLOB columns. Declaring
returns_native_bytes = True lets LargeBinary.result_processor skip the
redundant bytes() wrap on every cell and guards against a future
DefaultDialect default flip that would silently re-introduce the copy.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: antoineleclair

src/sqlalchemydqlite/base.py

@@ -74,6 +74,13 @@ class DqliteDialect(SQLiteDialect):
     # Enable SQLAlchemy statement caching
     supports_statement_cache = True
 
+    # dqlitedbapi returns native Python ``bytes`` for BLOB columns (the
+    # wire codec emits ``bytes`` for ``ValueType.BLOB``, and the
+    # PEP 249 ``Binary()`` constructor returns ``bytes``). Pin True
+    # locally so ``LargeBinary.result_processor`` can skip the redundant
+    # ``bytes(value)`` wrap on every BLOB cell.
+    returns_native_bytes = True
+
     # dqlite's wire protocol has a first-class BOOLEAN tag
     # (``ValueType.BOOLEAN = 11``); the server returns native Python
     # booleans for columns tagged BOOLEAN and dqlitedbapi passes them

tests/test_dialect.py

@@ -104,6 +104,15 @@ def test_insert_path_flags_pinned_locally(self, flag: str) -> None:
         assert getattr(DqliteDialect, flag) is True
         assert flag in DqliteDialect.__dict__
 
+    def test_returns_native_bytes_pinned_locally(self) -> None:
+        """dqlitedbapi returns native Python ``bytes`` for BLOB columns;
+        pin True locally so ``LargeBinary.result_processor`` skips the
+        redundant ``bytes(value)`` wrap on every BLOB cell, and so a
+        future DefaultDialect default flip cannot silently add overhead.
+        """
+        assert DqliteDialect.returns_native_bytes is True
+        assert "returns_native_bytes" in DqliteDialect.__dict__
+
     def test_dialect_description(self) -> None:
         # Pin the derived dialect_description so SQLAlchemy upgrades cannot
         # silently change the rendered identity in ORM error messages.