autogenerate_proxy_classes and proxies understanding

[FrancescJR]

Hello,

I just would like to understand more about the autogenerate_proxy_classes configuration. Maybe I don't need to understand it all, but just understand a specific behavior I am having that contradicts my understanding, hence the need for help.

So what I understand:

1. doctrine uses proxy objects (explained here: https://www.doctrine-project.org/projects/doctrine-orm/en/2.11/reference/advanced-configuration.html#auto-generating-proxy-classes-optional)
2. Proxy classes can either be generated manually or automatically at runtime by Doctrine (extract from docs).
   I am not sure if I have a configuration with this auto_generate_proxy_classes: true if that means it's automatically, I'd say so, right?

Now, what I don't understand is if proxy classes are eventually always used (independently if the config option) or just in some cases. I'd say that they are eventually always needed, despite on how they're generated, right?

But the behavior I'm having is:
if auto_generate_proxy_classes: true everything works fine (I can save entites to database normally)
if auto_generate_proxy_classes: false then I get this error: #7598 (yes the entity is "final")

But I'd say I should get the error always, maybe sooner or later, but I'd get the error too if I have a final class even though I have this auto_generate_proxy_classes: true, right?

Can somebody explain me the why behind all of this?