bug: (Rollup example) Hash function used in multiple locations but not Reset properly

[Engeloid]

Below it can be seen, that hfunc is used in the Sign() and Verify() function in transfer.go from the rollup example.

gnark/examples/rollup/transfer.go

Line 73 in 3d7377b

sigBin, err := priv.Sign(msg, hFunc)

Now this hash function is defined and initialized in operator.go, where it is being used for different kind of things, i.e., once you want to handle multiple transaction, where you sign/verify multiple transactions while also updating the state (e.g. in a loop where you create a transaction sign it and then update the state), the hash function will have input from previous (operator) operations and throw errors.

My workaround

I fixed this issue by defining another hash function in transfer.go and using that instead of hfunc.

Or was hfunc being used there for a reason? If so, please do enlighten me.