native: clear LastGasPerVote when voting for NULL

[AliceInHunterland]

Port neo-project/neo#3173.

Close #3345

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.67%. Comparing base (9c83bef) to head (0e6fbad).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3349      +/-   ##
==========================================
- Coverage   84.68%   84.67%   -0.01%     
==========================================
  Files         331      331              
  Lines       44932    44935       +3     
==========================================
  Hits        38050    38050              
- Misses       5371     5373       +2     
- Partials     1511     1512       +1     

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[AnnaShaleva]

Otherwise LGTM, the second test is not needed, since it'll require nontrivial modifications to cause error in the middle of voteInternal, just doesn't worth it.

[AnnaShaleva]

Second return value is not needed, it's enough that you've checked require.Equal(t, 4, len(res.Value().([]stackitem.Item))).

[AliceInHunterland]

but the fourth one is zero integer no need to check it?

[AnnaShaleva]

but the fourth one is zero integer no need to check it?

If you have 4 items, then (s *NEOBalance) FromStackItem will deserialize 4-th item in some particular value. And in test you check that this value is 0. That's enough.

My primary concern here was about the check that 4-th item is present.

[AnnaShaleva]

neo-go/pkg/core/state/native_state.go

Lines 162 to 168 in 9c83bef

	if len(structItem) >= 4 {
	lastGasPerVote, err := structItem[3].TryInteger()
	if err != nil {
	return fmt.Errorf("invalid last vote reward per neo stackitem: %w", err)
	}
	s.LastGasPerVote = *lastGasPerVote
	}