kvserver: remove weird v1-proposals code in propose

So glad to see this go.

pkg/kv/kvserver/replica_application_result.go

@@ -189,17 +189,13 @@ func (r *Replica) prepareLocalResult(ctx context.Context, cmd *replicatedCmd) {
 				}
 			}
 			if pErr == nil { // since we might have injected an error
-				if useReproposalsV2 {
-					pErr = kvpb.NewError(r.tryReproposeWithNewLeaseIndexV2(ctx, cmd))
-					if pErr == nil {
-						// Avoid falling through below. We managed to repropose, but this
-						// proposal is still erroring out. We don't want to assign to
-						// localResult. If there is an error though, we do fall through into
-						// the existing tangle of correct but unreadable handling below.
-						return
-					}
-				} else {
-					pErr = r.tryReproposeWithNewLeaseIndex(ctx, cmd)
+				pErr = kvpb.NewError(r.tryReproposeWithNewLeaseIndexV2(ctx, cmd))
+				if pErr == nil {
+					// Avoid falling through below. We managed to repropose, but this
+					// proposal is still erroring out. We don't want to assign to
+					// localResult. If there is an error though, we do fall through into
+					// the existing tangle of correct but unreadable handling below.
+					return
 				}
 			}
 
@@ -400,42 +396,6 @@ func (r *Replica) tryReproposeWithNewLeaseIndexV2(
 	return nil
 }
 
-// tryReproposeWithNewLeaseIndex is used by prepareLocalResult to repropose
-// commands that have gotten an illegal lease index error, and that we know
-// could not have applied while their lease index was valid (that is, we
-// observed all applied entries between proposal and the lease index becoming
-// invalid, as opposed to skipping some of them by applying a snapshot).
-//
-// It is not intended for use elsewhere and is only a top-level function so that
-// it can avoid the below_raft_protos check. Returns a nil error if the command
-// has already been successfully applied or has been reproposed here or by a
-// different entry for the same proposal that hit an illegal lease index error.
-func (r *Replica) tryReproposeWithNewLeaseIndex(
-	ctx context.Context, cmd *replicatedCmd,
-) *kvpb.Error {
-	// Note that we don't need to validate anything about the proposal's
-	// lease here - if we got this far, we know that everything but the
-	// index is valid at this point in the log.
-	p := cmd.proposal
-	if p.applied || cmd.Cmd.MaxLeaseIndex != p.command.MaxLeaseIndex {
-		// If the command associated with this rejected raft entry already
-		// applied then we don't want to repropose it. Doing so could lead
-		// to duplicate application of the same proposal.
-		//
-		// Similarly, if the command associated with this rejected raft
-		// entry has a different (larger) MaxLeaseIndex than the one we
-		// decoded from the entry itself, the command must have already
-		// been reproposed (this can happen if there are multiple copies
-		// of the command in the logs; see TestReplicaRefreshMultiple).
-		// We must not create multiple copies with multiple lease indexes,
-		// so don't repropose it again. This ensures that at any time,
-		// there is only up to a single lease index that has a chance of
-		// succeeding in the Raft log for a given command.
-		return nil
-	}
-	return r.tryReproposeWithNewLeaseIndexShared(ctx, cmd.proposal)
-}
-
 func (r *Replica) tryReproposeWithNewLeaseIndexShared(
 	ctx context.Context, p *ProposalData,
 ) *kvpb.Error {

pkg/kv/kvserver/replica_raft.go

@@ -356,34 +356,11 @@ func (r *Replica) propose(
 ) (pErr *kvpb.Error) {
 	defer tok.DoneIfNotMoved(ctx)
 
-	// If an error occurs reset the command's MaxLeaseIndex to its initial value.
-	// Failure to propose will propagate to the client. An invariant of this
-	// package is that proposals which are finished carry a raft command with a
-	// MaxLeaseIndex equal to the proposal command's max lease index.
-	defer func(prev kvpb.LeaseAppliedIndex) {
-		if useReproposalsV2 {
-			// The following poorly understood code is not necessary in V2 since
-			// we never mutate MaxLeaseIndex and don't hit propose() twice for
-			// the same *ProposalData.
-			return
-		}
-		if pErr != nil {
-			p.command.MaxLeaseIndex = prev
-		}
-	}(p.command.MaxLeaseIndex)
-
-	if !useReproposalsV2 {
-		// Make sure the maximum lease index is unset. This field will be set in
-		// propBuf.Insert and its encoded bytes will be appended to the encoding
-		// buffer as a MaxLeaseFooter.
-		p.command.MaxLeaseIndex = 0
-	} else {
-		if p.command.MaxLeaseIndex > 0 {
-			// TODO: there are a number of other fields that should still be unset.
-			// Verify them all. Some architectural improvements where we pass in a
-			// subset of ProposalData and then complete it here would be even better.
-			return kvpb.NewError(errors.AssertionFailedf("MaxLeaseIndex is set: %+v", p))
-		}
+	if p.command.MaxLeaseIndex > 0 {
+		// TODO: there are a number of other fields that should still be unset.
+		// Verify them all. Some architectural improvements where we pass in a
+		// subset of ProposalData and then complete it here would be even better.
+		return kvpb.NewError(errors.AssertionFailedf("MaxLeaseIndex is set: %+v", p))
 	}
 
 	if crt := p.command.ReplicatedEvalResult.ChangeReplicas; crt != nil {