Remove exception throwing from System.Runtime.GetInvocationCounter

[ixje]

Summary or problem description
We throw an error if the invocation counter is basically 0. It seems excessive to halt the contract execution for just asking for a counter value.

neo/src/neo/SmartContract/ApplicationEngine.Runtime.cs

Lines 159 to 164 in 0208a15

	protected internal int GetInvocationCounter()
	{
	if (!invocationCounter.TryGetValue(CurrentScriptHash, out var counter))
	throw new InvalidOperationException();
	return counter;
	}

Do you have any solution you want to propose?
remove the exception and return 0 instead

Neo Version

• Neo 3

Where in the software does this update applies to?

• Other: smart contracts / interop

[roman-khimov]

I guess it's more for the case when there is no CurrentScriptHash in the invocationCounter dictionary, which technically could only happen because of ApplicationEngine bug. And this case should be handled somehow, either by returning zero to the script (but it's not supposed to ever get zero for this call) or by halting the execution in some way (and that's what we have).

[shargon]

exactly it should never happen because we add it during the call

[ixje]

It is only added during a System.Contract.Call, but the entry script could arguably call System.Runtime.GetInvocationCounter on itself if it expects something like contract A.func1 call -> contract B.func1 call -> A.func2. Anyway, we'll see if that ever happens :)

[roman-khimov]

only happen because of ApplicationEngine bug

the entry script

Hmmm, maybe that's one of them, it's "called" implicitly, but still it's being run so it should be accounted for by invocationCounter. Especially for cases like verification with #1800 where a real contract is being loaded and it might use GetInvocationCounter for its purposes (which is not exactly expected from a simple transaction's entry script).

[ixje]

@roman-khimov should I re-open it?

[roman-khimov]

I think so. At least in my interpretation of this API the entry script (whatever that is) counts too.