feat: added GetSchema in CompiledConstraintSystem

[gbotrel]

No description provided.

[ivokub]

Hmm, I see the changes and they are good, but I do not get the motivation for including Schema as part of CCS. Is it building up for upcoming PR?

[gbotrel]

Well, in my mind, I have cases like a Prover / Verifier service, that'll have to potentially unmarshal json witnesses.
This is the case for example in the gnark playground.

We could probably store the schema away from the CCS , and leave it to the developer to handle that. But since schema is likely very cheap to store, I think it simplifies API to put in the CCS.

[gbotrel]

(but I did put it in a separate PR because it's up for discussion since there may be better option to do that)

[ivokub]

I see, makes sense. But wouldn't SetSchema() allow to create a conflicting state with CCS? It doesn't break CCS if the user sets invalid schema as it isn't used right now (? yet?).
I'll have to think it through a bit to understand more if there are any implications.

[gbotrel]

SetSchema is not exposed (i.e not defined on the interface CompiledConstraintSystem)

[ivokub]

I think it was getting late for me. I followed through where SetSchema was defined and it seems safe.