Apply current parses the yaml object 3 times

This is super expensive and not needed at all since we don't have to
reparse the entire object. Remove all allocations but the first one.

Author: Antoine Pelisse

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/fieldmanager/fieldmanager.go

@@ -216,7 +216,7 @@ func (f *fieldManager) Apply(liveObj runtime.Object, patch []byte, fieldManager
 	}
 	internal.RemoveObjectManagedFields(liveObjVersioned)
 
-	patchObjTyped, err := f.typeConverter.YAMLToTyped(patch)
+	patchObjTyped, err := f.typeConverter.ObjectToTyped(patchObj)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create typed patch object: %v", err)
 	}

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/fieldmanager/internal/BUILD

@@ -27,7 +27,6 @@ go_library(
         "//vendor/sigs.k8s.io/structured-merge-diff/merge:go_default_library",
         "//vendor/sigs.k8s.io/structured-merge-diff/typed:go_default_library",
         "//vendor/sigs.k8s.io/structured-merge-diff/value:go_default_library",
-        "//vendor/sigs.k8s.io/yaml:go_default_library",
     ],
 )
 

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/fieldmanager/internal/typeconverter.go

@@ -25,14 +25,12 @@ import (
 	"k8s.io/kube-openapi/pkg/util/proto"
 	"sigs.k8s.io/structured-merge-diff/typed"
 	"sigs.k8s.io/structured-merge-diff/value"
-	"sigs.k8s.io/yaml"
 )
 
 // TypeConverter allows you to convert from runtime.Object to
 // typed.TypedValue and the other way around.
 type TypeConverter interface {
 	ObjectToTyped(runtime.Object) (*typed.TypedValue, error)
-	YAMLToTyped([]byte) (*typed.TypedValue, error)
 	TypedToObject(*typed.TypedValue) (runtime.Object, error)
 }
 
@@ -58,11 +56,6 @@ func (DeducedTypeConverter) ObjectToTyped(obj runtime.Object) (*typed.TypedValue
 	return typed.DeducedParseableType.FromUnstructured(u)
 }
 
-// YAMLToTyped parses a yaml object into a TypedValue with a "deduced type".
-func (DeducedTypeConverter) YAMLToTyped(from []byte) (*typed.TypedValue, error) {
-	return typed.DeducedParseableType.FromYAML(typed.YAMLObject(from))
-}
-
 // TypedToObject transforms the typed value into a runtime.Object. That
 // is not specific to deduced type.
 func (DeducedTypeConverter) TypedToObject(value *typed.TypedValue) (runtime.Object, error) {
@@ -99,21 +92,6 @@ func (c *typeConverter) ObjectToTyped(obj runtime.Object) (*typed.TypedValue, er
 	return t.FromUnstructured(u)
 }
 
-func (c *typeConverter) YAMLToTyped(from []byte) (*typed.TypedValue, error) {
-	unstructured := &unstructured.Unstructured{Object: map[string]interface{}{}}
-
-	if err := yaml.Unmarshal(from, &unstructured.Object); err != nil {
-		return nil, fmt.Errorf("error decoding YAML: %v", err)
-	}
-
-	gvk := unstructured.GetObjectKind().GroupVersionKind()
-	t := c.parser.Type(gvk)
-	if t == nil {
-		return nil, newNoCorrespondingTypeError(gvk)
-	}
-	return t.FromYAML(typed.YAMLObject(string(from)))
-}
-
 func (c *typeConverter) TypedToObject(value *typed.TypedValue) (runtime.Object, error) {
 	return valueToObject(value.AsValue())
 }

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/fieldmanager/internal/typeconverter_test.go

@@ -124,9 +124,6 @@ spec:
 		t.Run(fmt.Sprintf("%v ObjectToTyped with TypeConverter", testCase.name), func(t *testing.T) {
 			testObjectToTyped(t, tc, testCase.yaml)
 		})
-		t.Run(fmt.Sprintf("%v YAMLToTyped with TypeConverter", testCase.name), func(t *testing.T) {
-			testYAMLToTyped(t, tc, testCase.yaml)
-		})
 		t.Run(fmt.Sprintf("%v ObjectToTyped with DeducedTypeConverter", testCase.name), func(t *testing.T) {
 			testObjectToTyped(t, dtc, testCase.yaml)
 		})
@@ -155,31 +152,9 @@ Final object:
 	}
 }
 
-func testYAMLToTyped(t *testing.T, tc internal.TypeConverter, y string) {
-	obj := &unstructured.Unstructured{Object: map[string]interface{}{}}
-	if err := yaml.Unmarshal([]byte(y), &obj.Object); err != nil {
-		t.Fatalf("Failed to parse yaml object: %v", err)
-	}
-	yamlTyped, err := tc.YAMLToTyped([]byte(y))
-	if err != nil {
-		t.Fatalf("Failed to convert yaml to typed: %v", err)
-	}
-	newObj, err := tc.TypedToObject(yamlTyped)
-	if err != nil {
-		t.Fatalf("Failed to convert typed to object: %v", err)
-	}
-	if !reflect.DeepEqual(obj, newObj) {
-		t.Errorf(`YAML conversion resulted in different object failed:
-Original object:
-%#v
-Final object:
-%#v`, obj, newObj)
-	}
-}
-
 var result typed.TypedValue
 
-func BenchmarkYAMLToTyped(b *testing.B) {
+func BenchmarkObjectToTyped(b *testing.B) {
 	y := `
 apiVersion: extensions/v1beta1
 kind: Deployment