Added code for fields with dots(.) in their names work as needed (#4591)

* Added code for fields with dots(.) in their names work as needed

Co-authored-by: sarjamil <sjamil@salesforce.com>

* Fixed imports

Co-authored-by: sarjamil <sjamil@salesforce.com>

* Removed comments

Co-authored-by: sarjamil <sjamil@salesforce.com>

* Fix filter method

Co-authored-by: sarjamil <sjamil@salesforce.com>

* Fixed failing tests

Co-authored-by: sarjamil <sjamil@salesforce.com>

* Remove comments

Add co-author to PR.

Co-authored-by: sarjamil <sjamil@salesforce.com>

* Add co-author to PR.

Co-authored-by: sarjamil sjamil@salesforce.com

Co-authored-by: sarjamil <sjamil@salesforce.com>

kyaml/yaml/rnode.go

@@ -15,6 +15,7 @@ import (
 	"sigs.k8s.io/kustomize/kyaml/errors"
 	"sigs.k8s.io/kustomize/kyaml/internal/forked/github.com/go-yaml/yaml"
 	"sigs.k8s.io/kustomize/kyaml/sliceutil"
+	"sigs.k8s.io/kustomize/kyaml/utils"
 	"sigs.k8s.io/kustomize/kyaml/yaml/internal/k8sgen/pkg/labels"
 )
 
@@ -1207,7 +1208,7 @@ func (rn *RNode) GetString(path string) (string, error) {
 // assuming we keep the var feature in kustomize.
 // The other end of this is: refvar.go:updateNodeValue.
 func (rn *RNode) GetFieldValue(path string) (interface{}, error) {
-	fields := convertSliceIndex(strings.Split(path, "."))
+	fields := convertSliceIndex(utils.SmarterPathSplitter(path, "."))
 	rn, err := rn.Pipe(Lookup(fields...))
 	if err != nil {
 		return nil, err

kyaml/yaml/rnode_test.go

@@ -2310,8 +2310,6 @@ func TestGetAnnotations(t *testing.T) {
 }
 
 func TestGetFieldValueWithDot(t *testing.T) {
-	t.Skip()
-
 	const input = `
 kind: Pod
 metadata:
@@ -2330,8 +2328,6 @@ metadata:
 	require.NoError(t, err)
 	require.Equal(t, "hello-world-app", app)
 
-	// TODO: doesn't currently work; we expect to be able to escape the dot in future
-	// https://github.com/kubernetes-sigs/kustomize/issues/4487
 	fooAppName, err := labelRNode.GetFieldValue(`foo\.appname`)
 	require.NoError(t, err)
 	require.Equal(t, "hello-world-foo", fooAppName) // no field named 'foo.appname'