Worked on the symfony/symfony repository to enhance the reliability of object mapping in PHP applications, focusing on the ObjectMapper component. Addressed two complex bugs over two months by refining how promoted and non-promoted constructor parameters are handled during data-to-object mapping. Improved the ObjectMapper to prevent exceptions when promoted constructor properties are missing from the source and ensured that non-promoted constructor parameters respect the class’s initialization logic. Added comprehensive unit tests and fixtures to validate these changes, increasing mapping accuracy and stability for downstream users. Utilized PHP development skills and unit testing to deliver robust, maintainable improvements to core functionality.