Merge pull request #68238 from justinsb/update_reflect2_to_101

Update reflect2 to 1.0.1 (memory utilization fix)

Kubernetes-commit: a94ea824eb59e92188f166c302d7995ba9002667

vendor/github.com/modern-go/reflect2/.travis.yml

@@ -6,6 +6,7 @@ go:
 
 before_install:
   - go get -t -v ./...
+  - go get -t -v github.com/modern-go/reflect2-tests/...
 
 script:
   - ./test.sh

vendor/github.com/modern-go/reflect2/Gopkg.toml

@@ -24,7 +24,7 @@
 #   go-tests = true
 #   unused-packages = true
 
-ignored = ["github.com/modern-go/test","github.com/modern-go/test/must","github.com/modern-go/test/should"]
+ignored = []
 
 [[constraint]]
   name = "github.com/modern-go/concurrent"

vendor/github.com/modern-go/reflect2/reflect2.go

@@ -150,6 +150,9 @@ func (cfg *frozenConfig) TypeOf(obj interface{}) Type {
 }
 
 func (cfg *frozenConfig) Type2(type1 reflect.Type) Type {
+	if type1 == nil {
+		return nil
+	}
 	cacheKey := uintptr(unpackEFace(type1).data)
 	typeObj, found := cfg.cache.Load(cacheKey)
 	if found {

vendor/github.com/modern-go/reflect2/test.sh

@@ -3,7 +3,7 @@
 set -e
 echo "" > coverage.txt
 
-for d in $(go list ./... | grep -v vendor); do
+for d in $(go list github.com/modern-go/reflect2-tests/... | grep -v vendor); do
     go test -coverprofile=profile.out -coverpkg=github.com/modern-go/reflect2 $d
     if [ -f profile.out ]; then
         cat profile.out >> coverage.txt

vendor/github.com/modern-go/reflect2/type_map.go

@@ -4,6 +4,7 @@ import (
 	"reflect"
 	"runtime"
 	"strings"
+	"sync"
 	"unsafe"
 )
 
@@ -15,10 +16,17 @@ func typelinks1() [][]unsafe.Pointer
 //go:linkname typelinks2 reflect.typelinks
 func typelinks2() (sections []unsafe.Pointer, offset [][]int32)
 
-var types = map[string]reflect.Type{}
-var packages = map[string]map[string]reflect.Type{}
+// initOnce guards initialization of types and packages
+var initOnce sync.Once
+
+var types map[string]reflect.Type
+var packages map[string]map[string]reflect.Type
+
+// discoverTypes initializes types and packages
+func discoverTypes() {
+	types = make(map[string]reflect.Type)
+	packages = make(map[string]map[string]reflect.Type)
 
-func init() {
 	ver := runtime.Version()
 	if ver == "go1.5" || strings.HasPrefix(ver, "go1.5.") {
 		loadGo15Types()
@@ -90,11 +98,13 @@ type emptyInterface struct {
 
 // TypeByName return the type by its name, just like Class.forName in java
 func TypeByName(typeName string) Type {
+	initOnce.Do(discoverTypes)
 	return Type2(types[typeName])
 }
 
 // TypeByPackageName return the type by its package and name
 func TypeByPackageName(pkgPath string, name string) Type {
+	initOnce.Do(discoverTypes)
 	pkgTypes := packages[pkgPath]
 	if pkgTypes == nil {
 		return nil