Contributed by
Christian Flothmann
in #29999.
The PropertyAccess component allows to read/write properties from objects and arrays using a simple string notation. It's used by Symfony components like Forms, Security, Validator, Workflow and hundreds of other public projects.
In Symfony 4.3 we improved its performance refactoring the code of theObjectNormalizer
class. The trick was to add some shortcuts for cases where
we know that we do not need to perform all checks.
Saving so many function calls in such a critical operation results in a20% to 30% performance improvement for a non-trivial synthetic benchmark. You can expect even better improvements if your app deals with large objects and complex property paths.

Best of all? You don't need to make any change in your application code to benefit from this improvement. Upgrade to Symfony 4.3 when it's released at the end of May 2019 and that's all.