Support YDB native UUID type

[vgvoleg]

Closes: #84

[Copilot]

Pull Request Overview

Adds support for YDB's native UUID type by introducing a custom SQLAlchemy type, mapping it in the compiler and dialect, and exercising it via new tests.

• Introduce YqlUUID to handle binding of uuid.UUID and string values into a native UUID column.
• Extend the SQL generation and YDB type mapping to recognize UUID and map it to ydb.PrimitiveType.UUID.
• Update the dialect’s type map and add tests for both native and string-based UUID columns.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
ydb_sqlalchemy/sqlalchemy/types.py	Added YqlUUID subclass with bind processor and stub result processor
ydb_sqlalchemy/sqlalchemy/compiler/sa20.py	Added visit_UUID and mapping logic in YqlTypeCompiler
ydb_sqlalchemy/sqlalchemy/init.py	Mapped YDB’s PrimitiveType.UUID to sa.UUID and registered YqlUUID
test/test_core.py	Imported uuid, defined test_uuid_types table and new tests for UUIDs

Comments suppressed due to low confidence (2)

test/test_core.py:322

• Add a test case for passing an invalid UUID string into the uuid_native column to verify that a ValueError is raised by the bind processor.

    def test_uuid_types(self, connection):

ydb_sqlalchemy/sqlalchemy/types.py:17

• [nitpick] Add a docstring for YqlUUID to describe its purpose and behavior for binding and result processing of native UUID values.

class YqlUUID(types.UUID):

[Copilot]

[nitpick] Consider moving the import uuid statement to the module level to avoid repeated imports inside the bind processor, improving clarity and performance.

Suggested change

	import uuid as uuid_module
	value = uuid_module.UUID(value)
	value = uuid.UUID(value)

[LuckySting]

Bump

[Copilot]

Consider implementing a result_processor to convert raw returned values (e.g., strings) back into uuid.UUID objects, ensuring consistent Python types.

Suggested change

	return None
	def process(value):
	if value is None:
	return None
	if isinstance(value, str):
	try:
	import uuid as uuid_module
	return uuid_module.UUID(value)
	except ValueError:
	raise ValueError(f"Invalid UUID string: {value}")
	return value
	return process

[LuckySting]

question: Shouldn't here be also uuid_str=uuid_value_str?

[LuckySting]

question: Since sa.Uuid is subtype of sa.UUID this block is unreachable. I think we need to consider sa.Uuid also as ydb.PrimitiveType.UUID, because sqlalchemy is designed in this way:

class Uuid(Emulated, TypeEngine[_UUID_RETURN]):
    """Represent a database agnostic UUID datatype.

    For backends that have no "native" UUID datatype, the value will
    make use of ``CHAR(32)`` and store the UUID as a 32-character alphanumeric
    hex string.

    For backends which are known to support ``UUID`` directly or a similar
    uuid-storing datatype such as SQL Server's ``UNIQUEIDENTIFIER``, a
    "native" mode enabled by default allows these types will be used on those
    backends.

Though it is not backward compatible for sure.

[LuckySting]

Bump

[LuckySting]

question: Why return None? Don't we need to either implement or to not touch this method?

[LuckySting]

suggestion: Let's try to unskip uuid tests in suite by removing @pytest.mark.skip("uuid unsupported for columns")

[LuckySting]

suggestion (non-blocking): Consider to add test that ydb.PrimitiveType.UUID column is correctly reflected to sa.UUID by calling metadata.reflect()