gnovm: decide maximum recursion depth perhaps defined by gas or with a preset maximum

[odeke-em]

I'd expect a smart contracting VM to have certain pre-defined limits that would control deep call routines and also memory limits because when I try to find the 60th Fibonacci number, this program hangs and most likely runs out of memory https://play.gno.land/p/FOEYk0mBinL

package hello

func main() {
	print(fib(60))
}

func fib(n int) int {
  if n <= 1 {
    return 1
  }
  return fib(n-1) + fib(n-2)
}

I think one way to reduce security blast radiuses is to particularly look at OpCall and for each function call graph, determine when it has run out of the allowed maximum recursion depth.

Solidity has a max recursion depth of 1024 per https://docs.soliditylang.org/en/latest/introduction-to-smart-contracts.html#message-calls

[kristovatlas]

Unless I'm missing something, the gas system does cause this to terminate.

package hello

func Main() int {
	return fib(60)
}

func fib(n int) int {
	if n <= 1 {
		return 1
	}
	return fib(n-1) + fib(n-2)
}

% gnokey maketx call --pkgpath "gno.land/r/kristovatlas/gno3549b" --func "Main" --gas-fee 10000000ugnot --gas-wanted 800000 --broadcast --remote localhost:26657 Dev
TX HASH:
--= Error =--
Data: allocation limit exceeded
Msg Traces:
    0  redacted/gno/tm2/pkg/errors/errors.go:28 - deliver transaction failed: log:msg:0,success:false,log:--= Error =--
Data: &errors.errorString{s:"allocation limit exceeded"}
Msg Traces:
    0  redacted/gno/gno.land/pkg/sdk/vm/keeper.go:513 - VM call panic: allocation limit exceeded
...snip...