[chore] update otel -> v1.20.0 (#2358)

vendor/google.golang.org/grpc/balancer/balancer.go

@@ -30,6 +30,7 @@ import (
 	"google.golang.org/grpc/channelz"
 	"google.golang.org/grpc/connectivity"
 	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/grpclog"
 	"google.golang.org/grpc/internal"
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/resolver"
@@ -39,6 +40,8 @@ import (
 var (
 	// m is a map from name to balancer builder.
 	m = make(map[string]Builder)
+
+	logger = grpclog.Component("balancer")
 )
 
 // Register registers the balancer builder to the balancer map. b.Name
@@ -51,6 +54,12 @@ var (
 // an init() function), and is not thread-safe. If multiple Balancers are
 // registered with the same name, the one registered last will take effect.
 func Register(b Builder) {
+	if strings.ToLower(b.Name()) != b.Name() {
+		// TODO: Skip the use of strings.ToLower() to index the map after v1.59
+		// is released to switch to case sensitive balancer registry. Also,
+		// remove this warning and update the docstrings for Register and Get.
+		logger.Warningf("Balancer registered with name %q. grpc-go will be switching to case sensitive balancer registries soon", b.Name())
+	}
 	m[strings.ToLower(b.Name())] = b
 }
 
@@ -70,6 +79,12 @@ func init() {
 // Note that the compare is done in a case-insensitive fashion.
 // If no builder is register with the name, nil will be returned.
 func Get(name string) Builder {
+	if strings.ToLower(name) != name {
+		// TODO: Skip the use of strings.ToLower() to index the map after v1.59
+		// is released to switch to case sensitive balancer registry. Also,
+		// remove this warning and update the docstrings for Register and Get.
+		logger.Warningf("Balancer retrieved for name %q. grpc-go will be switching to case sensitive balancer registries soon", name)
+	}
 	if b, ok := m[strings.ToLower(name)]; ok {
 		return b
 	}