chore: remove discrete view channels from mirror kernel

These were removed from other engine subsystems earlier but the mirror
kernel was overlooked by mistake. Now it only emits to the gossip
strategy output, as intended.

tm/tmengine/internal/tmmirror/internal/tmi/fixture_test.go

@@ -10,6 +10,7 @@ import (
 	"github.com/rollchains/gordian/tm/tmconsensus/tmconsensustest"
 	"github.com/rollchains/gordian/tm/tmengine/internal/tmeil"
 	"github.com/rollchains/gordian/tm/tmengine/internal/tmmirror/internal/tmi"
+	"github.com/rollchains/gordian/tm/tmengine/tmelink"
 	"github.com/rollchains/gordian/tm/tmstore/tmmemstore"
 )
 
@@ -24,7 +25,8 @@ type KernelFixture struct {
 
 	// These channels are bidirectional in the fixture,
 	// because they are write-only in the config.
-	VotingViewOutCh, CommittingViewOutCh chan tmconsensus.VersionedRoundView
+
+	GossipStrategyOut chan tmelink.NetworkViewUpdate
 
 	NHRRequests        chan chan tmi.NetworkHeightRound
 	SnapshotRequests   chan tmi.SnapshotRequest
@@ -43,8 +45,8 @@ type KernelFixture struct {
 func NewKernelFixture(t *testing.T, nVals int) *KernelFixture {
 	fx := tmconsensustest.NewStandardFixture(nVals)
 
-	votingViewOutCh := make(chan tmconsensus.VersionedRoundView)     // Unbuffered like in production.
-	committingViewOutCh := make(chan tmconsensus.VersionedRoundView) // Unbuffered like in production.
+	// Unbuffered because the kernel needs to know exactly what was received.
+	gso := make(chan tmelink.NetworkViewUpdate)
 
 	// 1-buffered like production:
 	// "because it is possible that the caller
@@ -73,8 +75,7 @@ func NewKernelFixture(t *testing.T, nVals int) *KernelFixture {
 
 		Fx: fx,
 
-		VotingViewOutCh:     votingViewOutCh,
-		CommittingViewOutCh: committingViewOutCh,
+		GossipStrategyOut: gso,
 
 		NHRRequests:        nhrRequests,
 		SnapshotRequests:   snapshotRequests,
@@ -100,9 +101,7 @@ func NewKernelFixture(t *testing.T, nVals int) *KernelFixture {
 			SignatureScheme:                   fx.SignatureScheme,
 			CommonMessageSignatureProofScheme: fx.CommonMessageSignatureProofScheme,
 
-			VotingViewOut:     votingViewOutCh,
-			CommittingViewOut: committingViewOutCh,
-
+			GossipStrategyOut:          gso,
 			StateMachineRoundActionsIn: smActionsIn,
 			StateMachineViewOut:        smViewOut,
 

tm/tmengine/internal/tmmirror/internal/tmi/kernel.go

@@ -37,14 +37,9 @@ type Kernel struct {
 
 	pbf tmelink.ProposedBlockFetcher
 
-	votingViewOut,
-	committingViewOut,
-	nextRoundViewOut chan<- tmconsensus.VersionedRoundView
-
 	gossipOutCh chan<- tmelink.NetworkViewUpdate
 
-	stateMachineIn      <-chan tmeil.StateMachineRoundActionSet
-	stateMachineViewOut chan<- tmconsensus.VersionedRoundView
+	stateMachineIn <-chan tmeil.StateMachineRoundActionSet
 
 	nhrRequests        <-chan chan NetworkHeightRound
 	snapshotRequests   <-chan SnapshotRequest
@@ -73,11 +68,6 @@ type KernelConfig struct {
 
 	ProposedBlockFetcher tmelink.ProposedBlockFetcher
 
-	// Views that are sent to the gossip strategy.
-	VotingViewOut,
-	CommittingViewOut,
-	NextRoundViewOut chan<- tmconsensus.VersionedRoundView
-
 	GossipStrategyOut chan<- tmelink.NetworkViewUpdate
 
 	StateMachineRoundActionsIn <-chan tmeil.StateMachineRoundActionSet
@@ -140,14 +130,9 @@ func NewKernel(ctx context.Context, log *slog.Logger, cfg KernelConfig) (*Kernel
 
 		// Channels provided through the config,
 		// i.e. channels coordinated by the Engine or Mirror.
-		votingViewOut:     cfg.VotingViewOut,
-		committingViewOut: cfg.CommittingViewOut,
-		nextRoundViewOut:  cfg.NextRoundViewOut,
-
 		gossipOutCh: cfg.GossipStrategyOut,
 
-		stateMachineIn:      cfg.StateMachineRoundActionsIn,
-		stateMachineViewOut: cfg.StateMachineViewOut,
+		stateMachineIn: cfg.StateMachineRoundActionsIn,
 
 		nhrRequests:        cfg.NHRRequests,
 		snapshotRequests:   cfg.SnapshotRequests,
@@ -218,7 +203,6 @@ func (k *Kernel) mainLoop(ctx context.Context, s *kState) {
 	defer close(k.done)
 
 	for {
-		vo := k.viewOutputs(s)
 		smOut := s.StateMachineView.Output(s)
 
 		gsOut := k.gossipStrategyOutput(s)
@@ -267,15 +251,6 @@ func (k *Kernel) mainLoop(ctx context.Context, s *kState) {
 		case req := <-k.addPrecommitRequests:
 			k.addPrecommit(ctx, s, req)
 
-		case vo.VotingCh <- vo.VotingVal:
-			s.Voting.Outgoing.MarkSent()
-
-		case vo.CommittingCh <- vo.CommittingVal:
-			s.Committing.Outgoing.MarkSent()
-
-		case vo.NextRoundCh <- vo.NextRoundVal:
-			s.NextRound.Outgoing.MarkSent()
-
 		case gsOut.Ch <- gsOut.Val:
 			gsOut.MarkSent(s)
 
@@ -1041,47 +1016,6 @@ func (k *Kernel) advanceVotingRound(s *kState) error {
 	return nil
 }
 
-// viewOutputs is the collection of channels and values
-// corresponding to round views that the Mirror tracks.
-type viewOutputs struct {
-	VotingCh  chan<- tmconsensus.VersionedRoundView
-	VotingVal tmconsensus.VersionedRoundView
-
-	CommittingCh  chan<- tmconsensus.VersionedRoundView
-	CommittingVal tmconsensus.VersionedRoundView
-
-	NextRoundCh  chan<- tmconsensus.VersionedRoundView
-	NextRoundVal tmconsensus.VersionedRoundView
-
-	// TODO: channels and values for NextHeight.
-}
-
-// kViewOutputs is a kernel method that returns a collection of
-// output channels and values to send on those channels.
-//
-// Any output channels that have already sent the most recent value,
-// will be set to nil so that no send is attempted.
-func (k *Kernel) viewOutputs(s *kState) viewOutputs {
-	var out viewOutputs
-
-	if !s.Voting.Outgoing.HasBeenSent() {
-		out.VotingCh = k.votingViewOut
-		out.VotingVal = s.Voting.Outgoing.VRV
-	}
-
-	if !s.Committing.Outgoing.HasBeenSent() {
-		out.CommittingCh = k.committingViewOut
-		out.CommittingVal = s.Committing.Outgoing.VRV
-	}
-
-	if !s.NextRound.Outgoing.HasBeenSent() {
-		out.NextRoundCh = k.nextRoundViewOut
-		out.NextRoundVal = s.NextRound.Outgoing.VRV
-	}
-
-	return out
-}
-
 type gossipStrategyOut struct {
 	Ch  chan<- tmelink.NetworkViewUpdate
 	Val tmelink.NetworkViewUpdate

tm/tmengine/internal/tmmirror/internal/tmi/kernel_test.go

@@ -46,9 +46,9 @@ func TestKernel_votesBeforeVotingRound(t *testing.T) {
 			kfx.Fx.SignProposal(ctx, &pb1, 0)
 
 			// Proposed blocks are sent directly.
-			_ = gtest.ReceiveSoon(t, kfx.VotingViewOutCh)
+			_ = gtest.ReceiveSoon(t, kfx.GossipStrategyOut)
 			gtest.SendSoon(t, kfx.AddPBRequests, pb1)
-			_ = gtest.ReceiveSoon(t, kfx.VotingViewOutCh)
+			_ = gtest.ReceiveSoon(t, kfx.GossipStrategyOut)
 
 			commitProof1 := kfx.Fx.PrecommitSignatureProof(
 				ctx,
@@ -78,7 +78,7 @@ func TestKernel_votesBeforeVotingRound(t *testing.T) {
 
 			// Confirm vote applied after being accepted
 			// (since the kernel does some work in the background here).
-			votingVRV := gtest.ReceiveSoon(t, kfx.VotingViewOutCh)
+			votingVRV := gtest.ReceiveSoon(t, kfx.GossipStrategyOut).Voting
 			require.Equal(t, uint64(2), votingVRV.Height)
 
 			// Update the fixture and go through the next height.
@@ -89,7 +89,7 @@ func TestKernel_votesBeforeVotingRound(t *testing.T) {
 			pb2 := kfx.Fx.NextProposedBlock([]byte("app_data_2"), 0)
 			kfx.Fx.SignProposal(ctx, &pb2, 0)
 			gtest.SendSoon(t, kfx.AddPBRequests, pb2)
-			_ = gtest.ReceiveSoon(t, kfx.VotingViewOutCh)
+			_ = gtest.ReceiveSoon(t, kfx.GossipStrategyOut)
 
 			commitProof2 := kfx.Fx.PrecommitSignatureProof(
 				ctx,
@@ -118,7 +118,7 @@ func TestKernel_votesBeforeVotingRound(t *testing.T) {
 			require.Equal(t, tmi.AddVoteAccepted, resp)
 
 			// Confirm on voting height 3.
-			votingVRV = gtest.ReceiveSoon(t, kfx.VotingViewOutCh)
+			votingVRV = gtest.ReceiveSoon(t, kfx.GossipStrategyOut).Voting
 			require.Equal(t, uint64(3), votingVRV.Height)
 
 			// Check if we need to advance the voting round.
@@ -149,7 +149,7 @@ func TestKernel_votesBeforeVotingRound(t *testing.T) {
 				require.Equal(t, tmi.AddVoteAccepted, resp)
 
 				// Confirm on voting height 3, round 1.
-				votingVRV = gtest.ReceiveSoon(t, kfx.VotingViewOutCh)
+				votingVRV = gtest.ReceiveSoon(t, kfx.GossipStrategyOut).Voting
 				require.Equal(t, uint64(3), votingVRV.Height)
 				require.Equal(t, uint32(1), votingVRV.Round)
 			}