Pin supports_sane_rowcount flags on the dialect

Matches the same drift-defence policy already applied to
supports_native_boolean, insert_returning, supports_multivalues_insert,
etc. The values mirror the current SQLiteDialect defaults; pinning
them on DqliteDialect itself prevents a future SQLAlchemy change to
the parent class from silently altering dqlite's rowcount semantics.

Author: antoineleclair

src/sqlalchemydqlite/base.py

@@ -147,6 +147,18 @@ class DqliteDialect(SQLiteDialect):
     # behaviour stays stable against upstream dialect drift.
     supports_multivalues_insert = True
 
+    # Rowcount truthfulness flags. SQLite (and therefore dqlite) reports
+    # accurate UPDATE / DELETE rowcounts and accurate aggregated
+    # executemany rowcounts. The two ``*_returning`` flags are False
+    # because SQLAlchemy's insertmanyvalues-with-RETURNING path relies
+    # on separate accounting; pinning False matches the inherited
+    # SQLiteDialect behaviour but, like the other pins above, guards
+    # against silent upstream drift.
+    supports_sane_rowcount = True
+    supports_sane_multi_rowcount = True
+    supports_sane_rowcount_returning = False
+    supports_sane_multi_rowcount_returning = False
+
     # Insert-path flags inherited from SQLiteDialect. SQLAlchemy's
     # insertmanyvalues codegen, DEFAULT VALUES form, and rowid handling
     # all key on these. Pin locally for the same "against upstream

tests/test_dialect_dialect_config.py

@@ -325,3 +325,26 @@ def test_is_disconnect_false_for_non_leader_codes(self, code: int) -> None:
         dialect = DqliteDialect()
         e = dqliteclient.exceptions.OperationalError(code, "application error")
         assert dialect.is_disconnect(e, None, None) is False
+
+
+class TestSupportsSaneRowcountFlags:
+    """Pin the ``supports_sane_rowcount`` quartet on the dialect class
+    itself (not merely inherited from ``SQLiteDialect``) so an upstream
+    change to the parent default cannot silently alter dqlite
+    behaviour. The values mirror the current SQLiteDialect defaults.
+    """
+
+    @pytest.mark.parametrize(
+        ("attr", "expected"),
+        [
+            ("supports_sane_rowcount", True),
+            ("supports_sane_multi_rowcount", True),
+            ("supports_sane_rowcount_returning", False),
+            ("supports_sane_multi_rowcount_returning", False),
+        ],
+    )
+    def test_flag_is_defined_on_dialect_class(self, attr: str, expected: bool) -> None:
+        assert attr in vars(DqliteDialect), (
+            f"{attr!r} must be defined on DqliteDialect, not merely inherited"
+        )
+        assert getattr(DqliteDialect, attr) is expected