Symfony version(s) affected

7.0.7, 6.4.7

Description

Recently after renovate upgrade bumping a few SF components (including serializer bump 6.4.6 -> 6.4.7) we noticed that our service started having performance problems on one endpoint.

CPU usage went to 100%, service autoscaled up to the limit and we've noticed on traces that service is getting stuck on processing not related to any IO operations.

What's specific about this endpoint is that we receive large json strings that are at some point getting serialized/deserialized and that's what got slow after upgrade.

At some point I even upgraded service to SF 7.0.7 and problem didn't go away.
It looks that downgrading to 6.4.6 or 7.0.6 helps, so I believe that root cause is here: symfony/serializer@v7.0.6...v7.0.7

I don't have any profiles that would tell exactly where it uses so much CPU the problem.

How to reproduce

I will do my best to prepare example repo later today.

Possible Solution

No response

Additional Context

We denormalize payload to an object that uses attributes with serialization group and public getters/setters.
See that changes between tags are related to that.

To test fixes, I prepared a load test using example payload (~850kb)

And p95 went to above 15s on 7.0.7.

Where on revision with a simple serializer dowgrade to 7.0.6 and exactly the same test it's back to normal: