fix: correct type checking for None values in code node output validation
- Fixed isinstance() checks to properly handle None values by checking None separately
- Fixed typo in STRING type validation where 'output_name' was hardcoded as string instead of variable
- Updated error message format to be consistent and more informative
- Updated test assertion to match new error message format
refactor(api): Separate SegmentType for Integer/Float to Enable Pydantic Serialization (#22025)
refactor(api): Separate SegmentType for Integer/Float to Enable Pydantic Serialization (#22025)
This PR addresses serialization issues in the VariablePool model by separating the `value_type` tags for `IntegerSegment`/`FloatSegment` and `IntegerVariable`/`FloatVariable`. Previously, both Integer and Float types shared the same `SegmentType.NUMBER` tag, causing conflicts during serialization.
Key changes:
- Introduce distinct `value_type` tags for Integer and Float segments/variables
- Add `VariableUnion` and `SegmentUnion` types for proper type discrimination
- Leverage Pydantic's discriminated union feature for seamless serialization/deserialization
- Enable accurate serialization of data structures containing these types
Closes #22024.