Add basic compatibility with SQLAlchemy 2.0 #414
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src/snowflake/sqlalchemy/base.py
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| @@ -296,7 +295,7 @@ def visit_aws_bucket(self, aws_bucket, **kw): | |||
| encryption_list.sort(key=operator.itemgetter(0)) | |||
| encryption = "ENCRYPTION=({})".format( | |||
| " ".join( | |||
| ("{}='{}'" if isinstance(v, string_types) else "{}={}").format(n, v) | |||
| ("{}='{}'" if isinstance(v, str) else "{}={}").format(n, v) | |||
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string_types no longer exists in SQLAlchemy 2.0. It used to be for Python 2 compatibility, but even in SQLAlchemy 1.4 it's just string_types = (str,).
| - array_type: not supported in snowflake | ||
| - uuid_data_type: not supported in snowflake |
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These are new properties (or at least new ones checked in the sqlalchemy test suite) that were added in 2.0. Since 1.4 simply doesn't check them, the addition is backwards-compatible.
| # no longer used for SQLAlchemy 2.0, so any value works | ||
| # String.RETURNS_UNICODE for backwards compatibility with 1.4 | ||
| returns_unicode_strings = ( | ||
| String.RETURNS_UNICODE if hasattr(String, "RETURNS_UNICODE") else None | ||
| ) |
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This is not necessary in 2.0, but kept for backwards-compatibility. String.RETURNS_UNICODE doesn't exist in 2.0.
| # Remove once support for sqlalchemy 1.4 is dropped | ||
| @classmethod | ||
| def dbapi(cls): | ||
| return cls.import_dbapi() | ||
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| @classmethod | ||
| def import_dbapi(cls): |
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Not a strictly necessary change, but produces a deprecation warning in 2.0.
| def has_table(self, connection, table_name, schema=None, **kw): | ||
| """ | ||
| Checks if the table exists | ||
| """ | ||
| return self._has_object(connection, "TABLE", table_name, schema) | ||
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| def has_sequence(self, connection, sequence_name, schema=None): | ||
| def has_sequence(self, connection, sequence_name, schema=None, **kw): |
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These functions get passed a new argument info_cache. Not certain what it is for, but kwargs makes this change backwards-compatible and we can keep the old implementation for now.
tests/test_core.py
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| @@ -423,7 +422,7 @@ def test_table_does_not_exist(engine_testaccount): | |||
| """ | |||
| meta = MetaData() | |||
| with pytest.raises(NoSuchTableError): | |||
| Table("does_not_exist", meta, autoload=True, autoload_with=engine_testaccount) | |||
| Table("does_not_exist", meta, autoload_with=engine_testaccount) | |||
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autoload is no longer a valid argument in 2.0. Code works fine without it in 1.4 as well.
tests/test_core.py
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| original_execute = inspector.bind.execute | ||
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| def mock_helper(command, *args, **kwargs): | ||
| if "_get_schema_columns" in command: | ||
| # Creating exception exactly how SQLAlchemy does | ||
| raise DBAPIError.instance( | ||
| """ | ||
| SELECT /* sqlalchemy:_get_schema_columns */ | ||
| ic.table_name, | ||
| ic.column_name, | ||
| ic.data_type, | ||
| ic.character_maximum_length, | ||
| ic.numeric_precision, | ||
| ic.numeric_scale, | ||
| ic.is_nullable, | ||
| ic.column_default, | ||
| ic.is_identity, | ||
| ic.comment | ||
| FROM information_schema.columns ic | ||
| WHERE ic.table_schema='schema_name' | ||
| ORDER BY ic.ordinal_position""", | ||
| {"table_schema": "TESTSCHEMA"}, | ||
| ProgrammingError( | ||
| "Information schema query returned too much data. Please repeat query with more " | ||
| "selective predicates.", | ||
| 90030, | ||
| ), | ||
| Error, | ||
| hide_parameters=False, | ||
| connection_invalidated=False, | ||
| dialect=SnowflakeDialect(), | ||
| ismulti=None, | ||
| ) | ||
| else: | ||
| return original_execute(command, *args, **kwargs) | ||
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| with patch.object(inspector.bind, "execute", side_effect=mock_helper): |
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This mock was actually unused in the test, as engine.execute was never called. Since engine.execute no longer exists in 2.0, I removed it.
tests/test_core.py
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| columns = table_reflected.columns | ||
| assert ( | ||
| len(columns) == len(ischema_names_baseline) - 1 | ||
| ) # -1 because FIXED is not supported | ||
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| def test_result_type_and_value(engine_testaccount): | ||
| with engine_testaccount.connect() as conn: | ||
| with engine_testaccount.begin() as conn: |
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Not starting a transaction explicitly was causing warnings. The code works in both versions still after this change.
tox.ini
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| @@ -114,6 +114,7 @@ markers = | |||
| timeout: tests that need a timeout time | |||
| internal: tests that could but should only run on our internal CI | |||
| external: tests that could but should only run on our external CI | |||
| backend: used in the sqlalchemy 2.0 test suite | |||
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SQLAlchemy 2.0 test suite adds a marker and since --strict-markers is set, pytest will refuse to run the tests without it added in the config. Doesn't affect 1.4.
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Should this restriction be removed in this PR? snowflake-sqlalchemy/setup.cfg Line 50 in e3f675e |
I'm unsure yet; the test failures make it seem that it wouldn't be fully compatible with 2.0 yet, though it will probably work for most use-cases. |
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Also if someone could approve the CI run, I'm interested whether my local setup behaves the same as the CI and whether the same tests fail. |
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Waiting to be merged ! |
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What GitHub issue is this PR addressing? Make sure that there is an accompanying issue to your PR.
Fixes (partially) SNOW-739749: snowflake-sqlalchemy 1.4.4 requires sqlalchemy<2.0.0,>=1.4.0, but you have sqlalchemy 2.0.1 which is incompatible. #380
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Please describe how your code solves the related issue.
Updates code which is incompatible with SQLAlchemy 2.0. See comments for why specific changes were done.
pytestall tests succeeded.pytest tests/sqlalchemy_test_suiteall tests succeeded.pytest --run_v20_sqlalchemyall tests succeeded.pytest --run_v20_sqlalchemy tests/sqlalchemy_test_suiterow count tests failed:pytest --run_v20_sqlalchemy(can't run without the flag, will error out) no tests failed.pytest --run_v20_sqlalchemy tests/sqlalchemy_test_suiterow count, date format, integer and some reflection caching tests failed (I assume newly added in 2.0):Not sure what to do about the failed tests - the row count ones failed during cleanup for me, so may work fine in CI. Datetime and integer-based tests are a bit more complicated as snowflake-sqlalchemy returns strings for datetimes and integer math works differently than decimal. The reflection caching could probably be fixed if I could figure out how it works 😅