chore: initialize some slice type variables (#4249)

core/bloom/bloom.go

@@ -105,7 +105,7 @@ func newRedisBitSet(store *redis.Redis, key string, bits uint) *redisBitSet {
 }
 
 func (r *redisBitSet) buildOffsetArgs(offsets []uint) ([]string, error) {
-	var args []string
+	args := make([]string, 0, len(offsets))
 
 	for _, offset := range offsets {
 		if offset >= r.bits {

core/breaker/breaker.go

@@ -269,7 +269,7 @@ func (ew *errorWindow) add(reason string) {
 }
 
 func (ew *errorWindow) String() string {
-	var reasons []string
+	reasons := make([]string, 0, ew.count)
 
 	ew.lock.Lock()
 	// reverse order

rest/httpc/requests.go

@@ -143,7 +143,7 @@ func fillPath(u *nurl.URL, val map[string]any) error {
 			delete(val, key)
 		}
 
-		var unused []string
+		unused := make([]string, 0, len(val))
 		for key := range val {
 			unused = append(unused, key)
 		}

rest/server.go

@@ -86,7 +86,7 @@ func (s *Server) PrintRoutes() {
 
 // Routes returns the HTTP routers that registered in the server.
 func (s *Server) Routes() []Route {
-	var routes []Route
+	routes := make([]Route, 0, len(s.ngin.routes))
 
 	for _, r := range s.ngin.routes {
 		routes = append(routes, r.routes...)
@@ -249,7 +249,7 @@ func WithNotAllowedHandler(handler http.Handler) RunOption {
 // WithPrefix adds group as a prefix to the route paths.
 func WithPrefix(group string) RouteOption {
 	return func(r *featuredRoutes) {
-		var routes []Route
+		routes := make([]Route, 0, len(r.routes))
 		for _, rt := range r.routes {
 			p := path.Join(group, rt.Path)
 			routes = append(routes, Route{

zrpc/internal/balancer/p2c/p2c.go

@@ -182,7 +182,7 @@ func (p *p2cPicker) choose(c1, c2 *subConn) *subConn {
 }
 
 func (p *p2cPicker) logStats() {
-	var stats []string
+	stats := make([]string, 0, len(p.conns))
 
 	p.lock.Lock()
 	defer p.lock.Unlock()

zrpc/resolver/internal/discovbuilder.go

@@ -22,8 +22,9 @@ func (b *discovBuilder) Build(target resolver.Target, cc resolver.ClientConn, _
 	}
 
 	update := func() {
-		var addrs []resolver.Address
+		vals := subset(sub.Values(), subsetSize)
-		for _, val := range subset(sub.Values(), subsetSize) {
+		addrs := make([]resolver.Address, 0, len(vals))
+		for _, val := range vals {
 			addrs = append(addrs, resolver.Address{
 				Addr: val,
 			})

zrpc/resolver/internal/kubebuilder.go

@@ -69,8 +69,9 @@ func (b *kubeBuilder) Build(target resolver.Target, cc resolver.ClientConn,
 	}
 
 	handler := kube.NewEventHandler(func(endpoints []string) {
-		var addrs []resolver.Address
+		endpoints = subset(endpoints, subsetSize)
-		for _, val := range subset(endpoints, subsetSize) {
+		addrs := make([]resolver.Address, 0, len(endpoints))
+		for _, val := range endpoints {
 			addrs = append(addrs, resolver.Address{
 				Addr: fmt.Sprintf("%s:%d", val, svc.Port),
 			})