fix(sqlalchemy-spanner): default supports_native_uuid to False for legacy Uuid compatibility

Author: sakthivelmanii

packages/sqlalchemy-spanner/google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py

@@ -775,10 +775,9 @@ class SpannerTypeCompiler(GenericTypeCompiler):
     """
 
     def visit_uuid(self, type_, **kw):
-        if not type_.native_uuid or not self.dialect.supports_native_uuid:
-            return self.visit_CHAR(types.CHAR(36), **kw)
-        else:
+        if type_.native_uuid and self.dialect.supports_native_uuid:
             return "UUID"
+        return "STRING(36)"
 
     def visit_INTEGER(self, type_, **kw):
         return "INT64"
@@ -862,7 +861,7 @@ class SpannerDialect(DefaultDialect):
     supports_identity_columns = True
     supports_native_boolean = True
     supports_native_decimal = True
-    supports_native_uuid = True
+    supports_native_uuid = False
     supports_statement_cache = True
     # Spanner uses protos for enums. Creating a column like
     # Column("an_enum", Enum("A", "B", "C")) will result in a String

packages/sqlalchemy-spanner/tests/mockserver_tests/test_uuid.py

@@ -35,38 +35,40 @@ def test_uuid_type_mapping(self):
     def test_uuid_designate_type(self):
         """Test reflecting UUID type string returns types.UUID."""
         dialect = SpannerDialect()
-        assert dialect.supports_native_uuid is True
+        assert dialect.supports_native_uuid is False
         col_type = dialect._designate_type("UUID")
         eq_(col_type, types.UUID)
 
     def test_uuid_ddl_compilation_default(self):
-        """Test DDL compilation emits UUID type by default when supports_native_uuid
-        is True.
+        """Test DDL compilation: types.Uuid emits STRING(36) by default and
+        types.UUID emits UUID by default.
         """
         dialect = SpannerDialect()
         metadata = MetaData()
         table = Table(
             "test_uuid_table",
             metadata,
-            Column("user_id", types.Uuid, primary_key=True),
+            Column("legacy_id", types.Uuid, primary_key=True),
+            Column("native_id", types.UUID),
         )
         statement = str(CreateTable(table).compile(dialect=dialect)).strip()
-        assert "user_id UUID NOT NULL" in statement
+        assert "legacy_id STRING(36) NOT NULL" in statement
+        assert "native_id UUID" in statement
 
-    def test_uuid_ddl_compilation_native_disabled(self):
-        """Test DDL compilation falls back to STRING(36) when supports_native_uuid
-        is False.
+    def test_uuid_ddl_compilation_native_enabled(self):
+        """Test DDL compilation emits UUID type for types.Uuid when supports_native_uuid
+        is set to True on dialect.
         """
         dialect = SpannerDialect()
-        dialect.supports_native_uuid = False
+        dialect.supports_native_uuid = True
         metadata = MetaData()
         table = Table(
             "test_uuid_table",
             metadata,
             Column("user_id", types.Uuid, primary_key=True),
         )
         statement = str(CreateTable(table).compile(dialect=dialect)).strip()
-        assert "user_id STRING(36) NOT NULL" in statement
+        assert "user_id UUID NOT NULL" in statement
 
     def test_uuid_python_conversion_legacy(self):
         """Test that types.Uuid automatically converts uuid.UUID to/from str