count votes from committee members only once

mysticeti/committee.nim

@@ -1,39 +1,7 @@
-import ./basics
-import ./signing
 import ./committee/members
+import ./committee/committee
+import ./committee/voting
 
-export members.CommitteeMember
-export members.`==`
-export members.`$`
-
-type
-  Committee*[Signing] = ref object
-    members: seq[Identifier[Signing]]
-    stakes: seq[Stake]
-  Stake* = float64
-
-func new*(_: type Committee, stakes: openArray[(Identifier, Stake)]): auto =
-  var committee = Committee[Identifier.Signing]()
-  for (member, stake) in stakes:
-    committee.members.add(member)
-    committee.stakes.add(stake)
-  committee
-
-func size*(committee: Committee): int =
-  committee.members.len
-
-func membership*(committee: Committee, identifier: Identifier): ?CommitteeMember =
-  let index = committee.members.find(identifier)
-  if index < 0:
-    none CommitteeMember
-  else:
-    some CommitteeMember(index)
-
-func stake*(committee: Committee, member: CommitteeMember): Stake =
-  committee.stakes[int(member)]
-
-func stake*(committee: Committee, identifier: Identifier): Stake =
-  if member =? committee.membership(identifier):
-    committee.stake(member)
-  else:
-    0
+export members
+export committee
+export voting

mysticeti/committee/committee.nim

@@ -0,0 +1,35 @@
+import ../basics
+import ../signing
+import ./members
+
+type
+  Committee*[Signing] = ref object
+    members: seq[Identifier[Signing]]
+    stakes: seq[Stake]
+  Stake* = float64
+
+func new*(_: type Committee, stakes: openArray[(Identifier, Stake)]): auto =
+  var committee = Committee[Identifier.Signing]()
+  for (member, stake) in stakes:
+    committee.members.add(member)
+    committee.stakes.add(stake)
+  committee
+
+func size*(committee: Committee): int =
+  committee.members.len
+
+func membership*(committee: Committee, identifier: Identifier): ?CommitteeMember =
+  let index = committee.members.find(identifier)
+  if index < 0:
+    none CommitteeMember
+  else:
+    some CommitteeMember(index)
+
+func stake*(committee: Committee, member: CommitteeMember): Stake =
+  committee.stakes[int(member)]
+
+func stake*(committee: Committee, identifier: Identifier): Stake =
+  if member =? committee.membership(identifier):
+    committee.stake(member)
+  else:
+    0

mysticeti/committee/voting.nim

@@ -0,0 +1,14 @@
+import ./members
+import ./committee
+
+type Voting* = object
+  voted: seq[CommitteeMember]
+  stake: Stake
+
+func add*(voting: var Voting, member: CommitteeMember, stake: Stake) =
+  if member notin voting.voted:
+    voting.voted.add(member)
+    voting.stake += stake
+
+func stake*(voting: Voting): Stake =
+  voting.stake

mysticeti/validator.nim

@@ -49,8 +49,9 @@ func updateSkipped(validator: Validator, supporter: Block) =
     for member in previous.members:
       let slot = previous[member]
       if supporter.skips(previous.number, member):
-        let stake = validator.committee.stake(supporter.author)
-        slot.skipBy(stake)
+        let author = supporter.author
+        let stake = validator.committee.stake(author)
+        slot.skipBy(author, stake)
 
 func updateCertified(validator: Validator, certificate: Block) =
   without certifying =? validator.rounds.latest.find(certificate.round) and
@@ -58,12 +59,14 @@ func updateCertified(validator: Validator, certificate: Block) =
           proposing =? voting.previous:
     return
   for proposal in proposing.proposals:
-    var support: Stake
+    var support: Voting
     for vote in voting.proposals:
       if proposal.blck.id in vote.blck.parents:
         if vote.blck.id in certificate.parents:
-          support += validator.committee.stake(vote.blck.author)
-    if support > 2/3:
+          let author = vote.blck.author
+          let stake = validator.committee.stake(author)
+          support.add(author, stake)
+    if support.stake > 2/3:
       let stake = validator.committee.stake(certificate.author)
       proposal.certifyBy(certificate.id, stake)
 

mysticeti/validator/slots.nim

@@ -5,12 +5,12 @@ import ../committee
 type
   ProposerSlot*[Signing, Hashing] = ref object
     proposals: seq[Proposal[Signing, Hashing]]
-    skippedBy: Stake
+    skippedBy: Voting
     status: SlotStatus
   Proposal*[Signing, Hashing] = ref object
     slot: ProposerSlot[Signing, Hashing]
     signedBlock: SignedBlock[Signing, Hashing]
-    certifiedBy: Stake
+    certifiedBy: Voting
     certificates: seq[BlockId[Hashing]]
   SlotStatus* {.pure.} = enum
     undecided
@@ -24,7 +24,7 @@ func proposals*(slot: ProposerSlot): auto =
 func proposal*(slot: ProposerSlot): auto =
   if slot.status in [SlotStatus.commit, SlotStatus.committed]:
     for proposal in slot.proposals:
-      if proposal.certifiedBy > 2/3:
+      if proposal.certifiedBy.stake > 2/3:
         return some proposal
 
 func status*(slot: ProposerSlot): auto =
@@ -41,13 +41,14 @@ func certificates*(proposal: Proposal): auto =
 
 func addProposal*(slot: ProposerSlot, signedBlock: SignedBlock) =
   let proposal = Proposal[SignedBlock.Signing, SignedBlock.Hashing](
-    slot: slot, signedBlock: signedBlock
+    slot: slot,
+    signedBlock: signedBlock
   )
   slot.proposals.add(proposal)
 
-func skipBy*(slot: ProposerSlot, stake: Stake) =
-  slot.skippedBy += stake
-  if slot.skippedBy > 2/3:
+func skipBy*(slot: ProposerSlot, member: CommitteeMember, stake: Stake) =
+  slot.skippedBy.add(member, stake)
+  if slot.skippedBy.stake > 2/3:
     slot.status = SlotStatus.skip
 
 func skip*(slot: ProposerSlot) =
@@ -57,20 +58,20 @@ func skip*(slot: ProposerSlot) =
 func commit*(slot: ProposerSlot): auto =
   assert slot.status == SlotStatus.commit
   let proposal = !slot.proposal
-  assert proposal.certifiedBy > 2/3
+  assert proposal.certifiedBy.stake > 2/3
   slot.status = SlotStatus.committed
   return proposal.blck
 
 func certifyBy*(proposal: Proposal, certificate: BlockId, stake: Stake) =
   proposal.certificates.add(certificate)
-  proposal.certifiedBy += stake
-  if proposal.certifiedBy > 2/3:
+  proposal.certifiedBy.add(certificate.author, stake)
+  if proposal.certifiedBy.stake > 2/3:
     proposal.slot.status = SlotStatus.commit
 
 func certify*(proposal, anchor: Proposal) =
   assert proposal.slot.status == SlotStatus.undecided
   assert anchor.slot.status == SlotStatus.commit
-  assert anchor.certifiedBy > 2/3
+  assert anchor.certifiedBy.stake > 2/3
   proposal.certificates = @[anchor.blck.id]
   proposal.certifiedBy = anchor.certifiedBy
   proposal.slot.status = SlotStatus.commit

tests/mysticeti/committee/testCommittee.nim

@@ -1,4 +1,4 @@
-import ./basics
+import ../basics
 import mysticeti/committee
 import mysticeti/signing
 

tests/mysticeti/committee/testVoting.nim

@@ -0,0 +1,25 @@
+import ../basics
+import mysticeti
+import mysticeti/committee
+
+suite "Committee Voting":
+
+  test "by default 0 stake has voted":
+    var voting: Voting
+    check voting.stake == 0
+
+  test "when a member adds a vote, it add its stake to the total":
+    var voting: Voting
+    voting.add(CommitteeMember(0), 1/8)
+    check voting.stake == 1/8
+    voting.add(CommitteeMember(1), 1/2)
+    check voting.stake == 5/8
+    voting.add(CommitteeMember(3), 1/8)
+    check voting.stake == 3/4
+
+  test "votes are only counted once":
+    var voting: Voting
+    voting.add(CommitteeMember(0), 1/8)
+    check voting.stake == 1/8
+    voting.add(CommitteeMember(0), 1/8)
+    check voting.stake == 1/8

tests/mysticeti/validator/testSlots.nim

@@ -85,11 +85,11 @@ suite "Proposer Slots":
     check slot.status == SlotStatus.committed
 
   test "slots can be skipped when >2/3 stake skip it":
-    slot.skipBy(1/3)
+    slot.skipBy(CommitteeMember(0), 1/3)
     check slot.status == SlotStatus.undecided
-    slot.skipBy(1/3)
+    slot.skipBy(CommitteeMember(1), 1/3)
     check slot.status == SlotStatus.undecided
-    slot.skipBy(1/1000)
+    slot.skipBy(CommitteeMember(2), 1/1000)
     check slot.status == SlotStatus.skip
 
   test "slots can be skipped immediately":

tests/tests.nim

@@ -1,5 +1,6 @@
-import ./mysticeti/testCommittee
 import ./mysticeti/testBlocks
+import ./mysticeti/committee/testCommittee
+import ./mysticeti/committee/testVoting
 import ./mysticeti/validator/testSlots
 import ./mysticeti/validator/testRound
 import ./mysticeti/validator/testRounds