if some process locks a block in round 0, then 0 is valid proposal.PO…

[melekes]

…LRound in rounds > 0

This condition is really hard to get. Initially, lockedRound and
validRound are set to -1 as we start with round 0.

Refs #2702

• Updated all relevant documentation in docs
• Updated all code comments where relevant
• Wrote tests
• Updated CHANGELOG_PENDING.md

[codecov-io]

Codecov Report

Merging #2704 into develop will increase coverage by 0.02%.
The diff coverage is 50%.

@@             Coverage Diff             @@
##           develop    #2704      +/-   ##
===========================================
+ Coverage    62.21%   62.23%   +0.02%     
===========================================
  Files          212      212              
  Lines        17136    17143       +7     
===========================================
+ Hits         10661    10669       +8     
  Misses        5577     5577              
+ Partials       898      897       -1

Impacted Files	Coverage Δ
consensus/state.go	79.78% <50%> (ø)	⬆️
libs/events/events.go	93.2% <0%> (-4.86%)	⬇️
libs/db/remotedb/remotedb.go	36.84% <0%> (-4.69%)	⬇️
libs/db/mem_db.go	82.9% <0%> (-2.39%)	⬇️
consensus/reactor.go	66.31% <0%> (-1.05%)	⬇️
p2p/pex/pex_reactor.go	73.05% <0%> (-0.33%)	⬇️
blockchain/pool.go	66.43% <0%> (+0.69%)	⬆️
privval/ipc_server.go	69.81% <0%> (+5.66%)	⬆️

[ebuchman]

Closing for #2735

@milosevic please confirm

[melekes]

I think changes here make the code better&more readable (NOTE they do not fix/change anything)

[ebuchman]

Ah right, happy to bring that in, but it looks like it changes the logic to allow POLRound to equal the current round which I don't think we want.

[melekes]

No, it will return err if proposal.POLRound >= proposal.Round