bug: Deserialization fails for large circuits

[liyue201]

Deserialization fails when the circuit reaches around 100 million constraints

panic: cbor: exceeded max number of elements 2147483647 for CBOR array

Description

Expected Behavior

Actual Behavior

Possible Fix

Steps to Reproduce

Context

Your Environment

• gnark v0.9.1

[readygo67]

could you provide more infos about this issue? for example

1. how many constraints of your circuit?
2. how to reproduce this problem?

[ivokub]

Interesting, the bound is 2^31, which is somewhat limited by the internal representation we use, and it is interesting to see that you hit the limit with smaller circuits. Are you sure the circuit has approximately 100M constraints? Imo we have tried using PLONK circuits of size approximately 2^27 and it serializes well.

What proof system (Groth16, PLONK) are you using and what is the exact constraint count?

[liyue201]

This place is over the limit

gnark/constraint/bn254/system.go

Line 159 in 3421eaa

dm, err := cbor.DecOptions{

I see that the latest code has been optimized and this problem should no longer exist.