Duplicate vote errors during the tests for 'nil' proposed block

[JekaMas]

Type:

Issue

What happened? / What do you need?:

At the moment we ignore all errors in client/knode/validator/validator.go on val.votingSystem.Add(addressVote).

One of the errors is a duplicate vote on prevote and vote stage:

INFO [07-12|09:24:16.428] Pre vote sub-election 
ERROR[07-12|09:24:16.430] a duplicate vote in voting table 0. Error: 
	Vote(ba8890175554d0f62551c453b1fdb988434c1780dc16675c2ea662599dc34ef6)
	Block Number:		30
	Block Hash:			0000000000000000000000000000000000000000000000000000000000000000
	Round:	  			0
	Type: 				0
	V:        			0x27
	R:        			0xf84e4561a704dd81237ce18cacd0defae2020228bf240df0f5a9780a555079
	S:        			0x79b753078f4bdaa92eaa0d9cfec8d5697ce237862757b70da1b07bee18edbaab
	Hex:      			f866a000000000000000000000000000000000000000000000000000000000000000001e8080279ff84e4561a704dd81237ce18cacd0defae2020228bf240df0f5a9780a555079a079b753078f4bdaa92eaa0d9cfec8d5697ce237862757b70da1b07bee18edbaab
 
WARN [07-12|09:24:16.430] Failed to add own vote to voting table   err="duplicate vote"
INFO [07-12|09:24:16.430] Waiting for a majority in the pre-vote sub-election 
INFO [07-12|09:24:16.430] There's a majority in the pre-vote sub-election! 
INFO [07-12|09:24:16.430] Pre commit sub-election 
ERROR[07-12|09:24:16.432] a duplicate vote in voting table 1. Error: 
	Vote(a7f78f200990c886e8ac306cc3dbab553174433cae50d1b408882744ce61a119)
	Block Number:		30
	Block Hash:			0000000000000000000000000000000000000000000000000000000000000000
	Round:	  			0
	Type: 				1
	V:        			0x27
	R:        			0xc5e163dc0ba10673f55274cd972aedb510ab49546df1f2b5bc0058390940eb96
	S:        			0x3703c773a58acf4983738905ab050f19da2f146c7beef21ec19bc144be0b06e7
	Hex:      			f867a000000000000000000000000000000000000000000000000000000000000000001e800127a0c5e163dc0ba10673f55274cd972aedb510ab49546df1f2b5bc0058390940eb96a03703c773a58acf4983738905ab050f19da2f146c7beef21ec19bc144be0b06e7

It happens quite a few times during e2e. And it can cause the reorg chain error: ERROR[07-12|09:24:11.003] Impossible reorg, please file an issue oldnum=26 oldhash=e2441a…15148c newnum=26 newhash=e2441a…15148c

I'm not sure it is safe to ignore this errors. @rgeraldes Could you advise about that? Is it expected behavior or the issue?

If it's an issue, how can we reproduce it?:

Run e2e tests with proper logging in client/knode/validator/validator.go

Priority:

Medium

[acroca]

Happened here: https://ci.kowala.io/kowala-tech/kcoin/2275/10

[JekaMas]

'not-nil' vote case is solved in https://github.com/kowala-tech/kcoin/pull/613

[JekaMas]

reorg error ERROR[07-12|09:24:11.003] Impossible reorg, please file an issue oldnum=26 oldhash=e2441a…15148c newnum=26 newhash=e2441a…15148c is solved in https://github.com/kowala-tech/kcoin/issues/642

[acroca]

It's happening now in the devnet with 2 validators