Pin the four insert-path dialect flags against upstream drift

SQLAlchemy's SQLiteDialect explicitly overrides four insert-path
flags that DefaultDialect sets to False: use_insertmanyvalues,
supports_default_metavalue, supports_default_values, and
insert_null_pk_still_autoincrements. The dqlite dialect inherited
them silently, so a version-gated change in a future SQLAlchemy
release could alter insert codegen, DEFAULT VALUES handling, or
rowid autoincrement behaviour without any signal on our side.

Declare all four locally in DqliteDialect with a comment block that
ties them back to the RETURNING and multivalues_insert pins already
present, and extend the parametrised pin test so re-inheritance
would fail the pin-tests immediately.

None of these flips observable behaviour today — the pinned values
match what SQLiteDialect already sets — this is documentation-as-
code plus a forward-compatibility guard.

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

Author: antoineleclair

src/sqlalchemydqlite/base.py

@@ -120,6 +120,17 @@ class DqliteDialect(SQLiteDialect):
     # behaviour stays stable against upstream dialect drift.
     supports_multivalues_insert = True
 
+    # 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
+    # drift" reason as the RETURNING trio above — a version-gated
+    # change in a future SQLAlchemy release would silently alter
+    # dqlite's insert behaviour otherwise.
+    use_insertmanyvalues = True
+    supports_default_metavalue = True
+    supports_default_values = True
+    insert_null_pk_still_autoincrements = True
+
     # Override the SQLite dialect's string-based DATE/DATETIME processors:
     # dqlitedbapi returns datetime objects (PEP 249), not ISO strings.
     colspecs = {

tests/test_dialect.py

@@ -1,5 +1,6 @@
 """Tests for dqlite dialect."""
 
+import pytest
 from sqlalchemy.engine import URL
 
 from sqlalchemydqlite import DqliteDialect
@@ -85,6 +86,24 @@ def test_update_returning_multifrom_pinned_locally(self) -> None:
         assert DqliteDialect.update_returning_multifrom is True
         assert "update_returning_multifrom" in DqliteDialect.__dict__
 
+    @pytest.mark.parametrize(
+        "flag",
+        [
+            "use_insertmanyvalues",
+            "supports_default_metavalue",
+            "supports_default_values",
+            "insert_null_pk_still_autoincrements",
+        ],
+    )
+    def test_insert_path_flags_pinned_locally(self, flag: str) -> None:
+        """SQLAlchemy's SQLiteDialect sets these four insert-path flags
+        explicitly. The dqlite dialect inherits them silently otherwise.
+        Pin locally so upstream version-gated changes cannot alter
+        insert codegen or rowid behaviour for dqlite.
+        """
+        assert getattr(DqliteDialect, flag) is True
+        assert flag 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.