[Flow EVM] Run tracing hooks OnTxStart, OnTxEnd for DryRunTransaction

[m-Peter]

work towards: onflow/flow-evm-gateway#530

This will allow us to generate traces for calls, to be used for debug_traceCall.

[m-Peter]

I am not sure if this should be before or after adjusting the txResult.GasConsumed with the various buffers.

[sideninja]

I think it's correct the way it is now

[sideninja]

txResult != nil this should always be true

[m-Peter]

I saw that proc.run can return nil for txResult in some cases:

if err != nil {
	return nil, err
}

Besides, this is the exact same condition for both RunTransaction & BatchRunTransaction, so I wanted to be on the safe side.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 6 lines in your changes missing coverage. Please review.

Project coverage is 41.47%. Comparing base (a573d77) to head (ee3c489).

Files with missing lines	Patch %	Lines
fvm/evm/emulator/emulator.go	0.00%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6491      +/-   ##
==========================================
- Coverage   41.48%   41.47%   -0.02%     
==========================================
  Files        2027     2027              
  Lines      144828   144834       +6     
==========================================
- Hits        60084    60071      -13     
- Misses      78538    78553      +15     
- Partials     6206     6210       +4     

Flag	Coverage Δ
unittests	41.47% <0.00%> (-0.02%)	⬇️

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[ramtinms]

the changes is okey to me, but I don't think we need to deploy it mainnet right away, if we are running the evm emulator offchain for this goal, then we could use a branch with these changes until post spork.

[m-Peter]

the changes is okey to me, but I don't think we need to deploy it mainnet right away, if we are running the evm emulator offchain for this goal, then we could use a branch with these changes until post spork.

@ramtinms I have found a way to achieve this functionality with the approach in: https://github.com/onflow/flow-evm-gateway/pull/567/files#diff-34c0f187c58bb59d36ca39cc631b07ba8f74d7f6886a5d6c6a796d721a928e67R244-R253.
What I am concerned about is this line:

// call tracer
tracer.OnTxStart(&tracing.VMContext{}, tx, from)

I am not entirely sure if I can populate this exactly as GetVMContext does:

// GetVMContext provides context about the block being executed as well as state
// to the tracers.
func (evm *EVM) GetVMContext() *tracing.VMContext {
	return &tracing.VMContext{
		Coinbase:    evm.Context.Coinbase,
		BlockNumber: evm.Context.BlockNumber,
		Time:        evm.Context.Time,
		Random:      evm.Context.Random,
		GasPrice:    evm.TxContext.GasPrice,
		ChainConfig: evm.ChainConfig(),
		StateDB:     evm.StateDB,
	}
}

Other than that, the approach on the EVM GW seems to work.

[ramtinms]

@m-Peter I think we should merge, my comment was for deployment given we never need tracer on the dryrun for onchain operations.

[janezpodhostnik]

Maybe we need to consider using a no-op tracer instead of nil, to get rid of all these checks and make it a bit cleaner. (Just a general comment, not really for this PR)