[N3] Request blocked funds

[shargon]

Description

Adds a function to recover locked funds after one year, requiring approval from 19 of 21 committee nodes. This recovery can only be executed once the period has elapsed and enforces the signature requirement to ensure security and consensus.

Type of change

• Optimization (the change is only an optimization)
• Style (the change is only a code style for better maintenance or standard purpose)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

• Unit Testing
• Run Application
• Local Computer Tests
• No Testing

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[erikzhang]

Looks good to me. Need #4271

[erikzhang]

Regarding waiting time, please vote. Six months = 👍, one year = ❤️, two years = 🎉.

[shargon]

Regarding waiting time, please vote. Six months = 👍, one year = ❤️, two years = 🎉.

Can one year be equivalent to the MaxTraceableBlocks? It's not the same, but it seems reasonable.

[erikzhang]

Can one year be equivalent to the MaxTraceableBlocks? It's not the same, but it seems reasonable.

I think they are two different things.

[superboyiii]

Now we have new exception:

[superboyiii]

The issue is: In RecoverFundsFinish, when calling transfer via CallContract, the new execution context wasn’t given NativeCallingScriptHash.

Suggested change

	try
	{
	engine.CallContract(contractHash, "transfer", CallFlags.All,
	new VM.Types.Array(engine.ReferenceCounter,
	[account.ToArray(), NativeContract.Treasury.Hash.ToArray(), balance, StackItem.Null]));
	// Execute transfer
	context = engine.CurrentContext;
	while (engine.InvocationStack.Contains(context!)) debugger.StepInto();
	// check result
	var result = engine.Pop().GetBoolean();
	if (!result)
	throw new InvalidOperationException($"Transfer of {balance} from {account} to {committeeMultiSigAddr} failed in contract {contractHash}.");
	}
	catch { throw; }
	finally
	{
	// Reset witnesses
	state.NativeCallingScriptHash = bak;
	}
	ExecutionContext? transferContext = null;
	UInt160? transferContextBak = null;
	try
	{
	engine.CallContract(contractHash, "transfer", CallFlags.All,
	new VM.Types.Array(engine.ReferenceCounter,
	[account.ToArray(), NativeContract.Treasury.Hash.ToArray(), balance, StackItem.Null]));
	// Set NativeCallingScriptHash for the new context to allow transfer to pass witness check
	transferContext = engine.CurrentContext;
	var transferContextState = transferContext.GetState<ExecutionContextState>();
	transferContextBak = transferContextState.NativeCallingScriptHash;
	transferContextState.NativeCallingScriptHash = account;
	// Execute transfer
	while (engine.InvocationStack.Contains(transferContext!)) debugger.StepInto();
	// check result
	var result = engine.Pop().GetBoolean();
	if (!result)
	throw new InvalidOperationException($"Transfer of {balance} from {account} to {NativeContract.Treasury.Hash} failed in contract {contractHash}.");
	}
	catch { throw; }
	finally
	{
	// Reset witnesses
	if (transferContext != null)
	{
	var transferContextState = transferContext.GetState<ExecutionContextState>();
	transferContextState.NativeCallingScriptHash = transferContextBak;
	}
	state.NativeCallingScriptHash = bak;
	}

[shargon]

I will try with @roman-khimov idea

[erikzhang]

Does it need an event?

[erikzhang]

Alternatively, it would also be acceptable if there were events for blocking and unblocking accounts.

[shargon]

#4387

[erikzhang]

Maybe we can transfer tokens one by one?

[shargon]

Then we can't reset

[erikzhang]

Now we can transfer tokens one by one.

[shargon]

@superboyiii I receive an error in your UT in CalculateBonus:

var expectEnd = Ledger.CurrentIndex(snapshot) + 1;
if (expectEnd != end) throw new ArgumentOutOfRangeException(nameof(end));
if (state.BalanceHeight >= end) return BigInteger.Zero;

But it should work with real environment

[shargon]

Require #4388