add legacy filter to image tag transformer

api/builtins/ImageTagTransformer.go

@@ -31,14 +31,15 @@ func (p *ImageTagTransformerPlugin) Config(
 
 func (p *ImageTagTransformerPlugin) Transform(m resmap.ResMap) error {
 	for _, r := range m.Resources() {
-		// If you're here because someone expected any field containing
-		// the string "containers" or "initContainers" to get an image
-		// update (not just spec/template/spec/containers[], etc.) then
-		// a code change is needed.  See api/filters/imagetag/legacy
-		// for the start of an implementation that won't use an
-		// allowlist like FsSlice, and instead walks the object looking
-		// for fields named containers or initContainers.
-		err := filtersutil.ApplyToJSON(imagetag.Filter{
+		// traverse all fields at first
+		err := filtersutil.ApplyToJSON(imagetag.LegacyFilter{
+			ImageTag: p.ImageTag,
+		}, r)
+		if err != nil {
+			return err
+		}
+		// then use user specified field specs
+		err = filtersutil.ApplyToJSON(imagetag.Filter{
 			ImageTag: p.ImageTag,
 			FsSlice:  p.FieldSpecs,
 		}, r)

api/krusty/transformersimage_test.go

@@ -215,25 +215,25 @@ spec2:
   template:
     spec:
       containers:
-      - image: nginx:v1
+      - image: nginx:v2
         name: nginx3
-      - image: my-nginx:latest
+      - image: my-nginx:previous
         name: nginx4
 spec3:
   template:
     spec:
       initContainers:
-      - image: postgres:alpine-9
+      - image: my-postgres:v3
         name: postgresdb
-      - image: docker:17-git
+      - image: my-docker@sha256:25a0d4b4
         name: init-docker
-      - image: myprivaterepohostname:1234/my/image:latest
+      - image: myprivaterepohostname:1234/my/image:v1.0.1
         name: myImage
-      - image: myprivaterepohostname:1234/my/image
+      - image: myprivaterepohostname:1234/my/image:v1.0.1
         name: myImage2
       - image: my-app-image:v1
         name: my-app
-      - image: gcr.io:8080/my-project/my-cool-app:latest
+      - image: my-cool-app:latest
         name: my-cool-app
 `)
 }