Simplify imports and improve comments.

server/etcdserver/api/v3rpc/header.go

@@ -17,13 +17,13 @@ package v3rpc
 import (
 	pb "go.etcd.io/etcd/api/v3/etcdserverpb"
 	"go.etcd.io/etcd/server/v3/etcdserver"
-	apply2 "go.etcd.io/etcd/server/v3/etcdserver/apply"
+	"go.etcd.io/etcd/server/v3/etcdserver/apply"
 )
 
 type header struct {
 	clusterID int64
 	memberID  int64
-	sg        apply2.RaftStatusGetter
+	sg        apply.RaftStatusGetter
 	rev       func() int64
 }
 

server/etcdserver/api/v3rpc/watch.go

@@ -26,7 +26,7 @@ import (
 	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
 	"go.etcd.io/etcd/server/v3/auth"
 	"go.etcd.io/etcd/server/v3/etcdserver"
-	apply2 "go.etcd.io/etcd/server/v3/etcdserver/apply"
+	"go.etcd.io/etcd/server/v3/etcdserver/apply"
 	"go.etcd.io/etcd/server/v3/storage/mvcc"
 
 	"go.uber.org/zap"
@@ -42,7 +42,7 @@ type watchServer struct {
 
 	maxRequestBytes int
 
-	sg        apply2.RaftStatusGetter
+	sg        apply.RaftStatusGetter
 	watchable mvcc.WatchableKV
 	ag        AuthGetter
 }
@@ -125,7 +125,7 @@ type serverWatchStream struct {
 
 	maxRequestBytes int
 
-	sg        apply2.RaftStatusGetter
+	sg        apply.RaftStatusGetter
 	watchable mvcc.WatchableKV
 	ag        AuthGetter
 

server/etcdserver/apply/uber_applier.go

@@ -104,6 +104,8 @@ func (a *UberApplier) RestoreAlarms() {
 }
 
 func (a *UberApplier) Apply(r *pb.InternalRaftRequest, shouldApplyV3 membership.ShouldApplyV3) *ApplyResult {
+	// We first execute chain of WrapApply across all objects (e.g. CorruptApplier -> CappedApplier -> Auth -> Quota -> Backend),
+	// than dispatch(), than individual methods wrappers CorruptApplier.Put(CappedApplier.Put(... BackendApplier.Put())))
 	return a.applyV3.WrapApply(context.TODO(), r, shouldApplyV3, a.dispatch)
 }
 
@@ -139,7 +141,6 @@ func (a *UberApplier) dispatch(ctx context.Context, r *pb.InternalRaftRequest, s
 		return nil
 	}
 
-	// call into a.s.applyV3.F instead of a.F so upper appliers can check individual calls
 	switch {
 	case r.Range != nil:
 		op = "Range"

server/etcdserver/server_test.go

@@ -1606,7 +1606,7 @@ func TestUpdateVersion(t *testing.T) {
 	srv := &EtcdServer{
 		lgMu:       new(sync.RWMutex),
 		lg:         zaptest.NewLogger(t),
-		memberId:         1,
+		memberId:   1,
 		Cfg:        config.ServerConfig{Logger: zaptest.NewLogger(t), TickMs: 1, SnapshotCatchUpEntries: DefaultSnapshotCatchUpEntries},
 		r:          *newRaftNode(raftNodeConfig{lg: zaptest.NewLogger(t), Node: n}),
 		attributes: membership.Attributes{Name: "node1", ClientURLs: []string{"http://node1.com"}},