Automated cherry pick of #114863: Use label selector for filtering out resources when pruning. #115571: Add integration test for diff --prune --selector

staging/src/k8s.io/kubectl/pkg/cmd/diff/diff.go

@@ -649,7 +649,7 @@ func (o *DiffOptions) Complete(f cmdutil.Factory, cmd *cobra.Command) error {
 		if err != nil {
 			return err
 		}
-		o.pruner = newPruner(o.DynamicClient, mapper, resources)
+		o.pruner = newPruner(o.DynamicClient, mapper, resources, o.Selector)
 	}
 
 	o.Builder = f.NewBuilder()

staging/src/k8s.io/kubectl/pkg/cmd/diff/prune.go

@@ -40,13 +40,14 @@ type pruner struct {
 	resources         []prune.Resource
 }
 
-func newPruner(dc dynamic.Interface, m meta.RESTMapper, r []prune.Resource) *pruner {
+func newPruner(dc dynamic.Interface, m meta.RESTMapper, r []prune.Resource, selector string) *pruner {
 	return &pruner{
 		visitedUids:       sets.NewString(),
 		visitedNamespaces: sets.NewString(),
 		dynamicClient:     dc,
 		mapper:            m,
 		resources:         r,
+		labelSelector:     selector,
 	}
 }
 

test/cmd/diff.sh

@@ -111,6 +111,89 @@ run_kubectl_diff_tests() {
     # Cleanup
     kubectl delete -f hack/testdata/pod.yaml
     kubectl delete -f hack/testdata/prune/b.yaml
+    kubectl delete namespace nsb
+
+    ## kubectl diff --prune with label selector
+    kubectl create ns nsbprune
+    kubectl apply --namespace nsbprune -f - <<EOF
+apiVersion: v1
+kind: Pod
+metadata:
+  name: a
+  namespace: nsbprune
+  labels:
+    prune-group: "true"
+spec:
+  containers:
+  - name: kubernetes-pause
+    image: registry.k8s.io/pause:3.9
+---
+apiVersion: v1
+kind: Pod
+metadata:
+  name: b
+  namespace: nsbprune
+  labels:
+    prune-group: "true"
+spec:
+  containers:
+    - name: kubernetes-pause
+      image: registry.k8s.io/pause:3.9
+---
+apiVersion: v1
+kind: Pod
+metadata:
+  name: c
+  namespace: nsbprune
+  labels:
+    prune-group: "false"
+spec:
+  containers:
+    - name: kubernetes-pause
+      image: registry.k8s.io/pause:3.9
+EOF
+    kube::test::get_object_assert 'pods a -n nsbprune' "{{${id_field:?}}}" 'a'
+    kube::test::get_object_assert 'pods b -n nsbprune' "{{${id_field:?}}}" 'b'
+    kube::test::get_object_assert 'pods c -n nsbprune' "{{${id_field:?}}}" 'c'
+    # Make sure that kubectl diff does not return either pod 'b' or pod 'c' without prune flag
+    PRUNE=$(cat <<EOF
+apiVersion: v1
+kind: Pod
+metadata:
+  name: a
+  namespace: nsbprune
+  labels:
+    prune-group: "true"
+spec:
+  containers:
+  - name: kubernetes-pause
+    image: registry.k8s.io/pause:3.9
+---
+apiVersion: v1
+kind: Pod
+metadata:
+  name: c
+  namespace: nsbprune
+  labels:
+    prune-group: "false"
+spec:
+  containers:
+    - name: kubernetes-pause
+      image: registry.k8s.io/pause:3.9
+EOF
+)
+    output_message=$(echo "${PRUNE}" | kubectl diff -l prune-group=true -f -)
+    kube::test::if_has_not_string "${output_message}" "name: b"
+    kube::test::if_has_not_string "${output_message}" "name: c"
+    # the exit code for diff is 1 because pod 'b' is found in the given label selector but not 'c'
+    output_message=$(echo "${PRUNE}" | kubectl diff --prune -l prune-group=true -f - || test $? -eq 1)
+    # pod 'b' should be in output, it is pruned. On the other hand, 'c' should not be, it's label selector is different
+    kube::test::if_has_string "${output_message}" 'name: b'
+    kube::test::if_has_not_string "${output_message}" "name: c"
+
+    # Cleanup
+    kubectl delete namespace nsbprune
+
 
     set +o nounset
     set +o errexit