Pin supports_server_side_cursors False on the async dialect

dqlite has no server-side cursor notion at the wire protocol level.
Pin the flag on DqliteDialect_aio so a future default flip in
SQLAlchemy's AsyncDialect cannot silently route the dqlite async
engine through an SS-cursor code path the adapter does not implement.

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

Author: antoineleclair

src/sqlalchemydqlite/aio.py

@@ -208,6 +208,14 @@ class DqliteDialect_aio(DqliteDialect):  # noqa: N801
     # warning fires on every engine startup.
     supports_statement_cache = True
 
+    # dqlite has no server-side cursor notion at the wire level — rows
+    # arrive in frames that the client fully consumes before surfacing
+    # them, and the adapter eagerly buffers into a deque. Pin False
+    # locally so a future base-class default flip (e.g. AsyncDialect
+    # defaulting True the way aiosqlite does) cannot silently route
+    # through an SS-cursor code path the adapter does not implement.
+    supports_server_side_cursors = False
+
     @classmethod
     def get_pool_class(cls, url: URL) -> type[pool.Pool]:
         return AsyncAdaptedQueuePool

tests/test_dialect.py

@@ -104,6 +104,17 @@ def test_insert_path_flags_pinned_locally(self, flag: str) -> None:
         assert getattr(DqliteDialect, flag) is True
         assert flag in DqliteDialect.__dict__
 
+    def test_supports_server_side_cursors_pinned_false_on_aio(self) -> None:
+        """dqlite has no server-side cursor notion; pin locally on the
+        async dialect so an upstream AsyncDialect default flip cannot
+        silently route through an SS-cursor code path we do not
+        implement.
+        """
+        from sqlalchemydqlite.aio import DqliteDialect_aio
+
+        assert DqliteDialect_aio.supports_server_side_cursors is False
+        assert "supports_server_side_cursors" in DqliteDialect_aio.__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