Fix kubectl explain bug when additionalProperties in schema defines as boolean. (#124506)

* Fix kubectl explain bug when additionalProperties in schema defines as:
`additionalProperties: true` to ignore iterating.

* trigger error on kubectl explain with integration test on crd with non bool additionalfields

* add changes to fix the problem

* replace sleep with loop and retry for kubectl explain integration test

* replaced testdata file with inline create

staging/src/k8s.io/kubectl/pkg/explain/v2/templates/plaintext.tmpl

@@ -118,7 +118,7 @@ Takes dictionary as argument with keys:
     {{- else if $resolved.items -}}
         {{- /* If the schema is an array then traverse the array item fields */ -}}
         {{- template "output" (set $nextContext "schema" $resolved.items) -}}
-    {{- else if $resolved.additionalProperties -}}
+    {{- else if and $resolved.additionalProperties (not (eq "bool" (printf "%T" $resolved.additionalProperties))) -}}
         {{- /* If the schema is a map then traverse the map item fields */ -}}
         {{- template "output" (set $nextContext "schema" $resolved.additionalProperties) -}}
     {{- else -}}
@@ -182,7 +182,9 @@ Takes dictionary as argument with keys:
             {{- template "fieldList" (set $nextContext "schema" .)}}
         {{- end -}}
         {{- if $resolved.items}}{{- template "fieldList" (set $nextContext "schema" $resolved.items)}}{{end}}
-        {{- if $resolved.additionalProperties}}{{- template "fieldList" (set $nextContext "schema" $resolved.additionalProperties)}}{{end}}
+        {{- if and $resolved.additionalProperties (not (eq "bool" (printf "%T" $resolved.additionalProperties))) -}}
+            {{- template "fieldList" (set $nextContext "schema" $resolved.additionalProperties)}}
+        {{- end -}}
     {{- end -}}
 {{- end -}}
 
@@ -235,7 +237,7 @@ Takes dictionary as argument with keys:
         {{- if .items -}}
             {{- template "description" (set $ "schema" .items) -}}
         {{- end -}}
-        {{- if .additionalProperties -}}
+        {{- if and .additionalProperties (not (eq "bool" (printf "%T" .additionalProperties))) -}}
             {{- template "description" (set $ "schema" .additionalProperties) -}}
         {{- end -}}
     {{- end -}}
@@ -256,7 +258,7 @@ Takes dictionary as argument with keys:
     {{- with $.schema -}}
         {{- if .items -}}
             []{{template "typeGuess" (set $ "schema" .items)}}
-        {{- else if .additionalProperties -}}
+        {{- else if and .additionalProperties (not (eq "bool" (printf "%T" .additionalProperties))) -}}
             map[string]{{template "typeGuess" (set $ "schema" .additionalProperties)}}
         {{- else if and .allOf (not .properties) (eq (len .allOf) 1) -}}
             {{- /* If allOf has a single element and there are no direct

staging/src/k8s.io/kubectl/pkg/explain/v2/templates/plaintext_test.go

@@ -392,6 +392,20 @@ func TestPlaintext(t *testing.T) {
 				checkEquals("string"),
 			},
 		},
+		{
+			// Shows that the typeguess template works with boolean additionalProperties
+			Name:        "True additionalProperties",
+			Subtemplate: "typeGuess",
+			Context: map[string]any{
+				"schema": map[string]any{
+					"type":                 "string",
+					"additionalProperties": true,
+				},
+			},
+			Checks: []check{
+				checkEquals("string"),
+			},
+		},
 		{
 			// Show that a ref to a primitive type uses the referred type's type
 			Name:        "PrimitiveRef",

test/cmd/discovery.sh

@@ -407,3 +407,73 @@ __EOF__
   set +o nounset
   set +o errexit
 }
+
+run_explain_crd_with_additional_properties_tests() {
+  set -o nounset
+  set -o errexit
+
+  create_and_use_new_namespace
+  kube::log::status "Testing explain with custom CRD that uses additionalProperties as non boolean field"
+
+  kubectl create -f - << __EOF__
+apiVersion: apiextensions.k8s.io/v1
+kind: CustomResourceDefinition
+metadata:
+  name: mock-resources.test.com
+spec:
+  group: test.com
+  scope: Namespaced
+  names:
+    plural: mock-resources
+    singular: mock-resource
+    kind: MockResource
+    listKind: MockResources
+  versions:
+    - name: v1
+      storage: true
+      served: true
+      schema:
+        openAPIV3Schema:
+          type: object
+          properties:
+            spec:
+              type: object
+              properties:
+                test:
+                  type: object
+                  additionalProperties:
+                    type: array
+                    items:
+                      type: string
+              additionalProperties: true
+__EOF__
+
+  kube::test::wait_object_assert customresourcedefinitions "{{range.items}}{{if eq ${id_field:?} \"mock-resources.test.com\"}}{{$id_field}}:{{end}}{{end}}" 'mock-resources.test.com:'
+
+  retries=0
+  max_retries=5
+
+  # First try would get non zero exit code so we disable immediate exit here
+  set +o errexit
+
+  # Loop until `kubectl explain` returns a zero exit code or maximum retries reached
+  until output_message=$(kubectl explain mock-resource) > /dev/null || [ $retries -eq $max_retries ]; do
+    kube::log::status "Retrying kubectl explain..."
+    ((retries++))
+    sleep 1
+  done
+
+  set -o errexit
+
+  output_message=$(kubectl explain mock-resource)
+  kube::test::if_has_string "${output_message}" 'FIELDS:'
+
+  output_message=$(kubectl explain mock-resource --recursive)
+  kube::test::if_has_string "${output_message}" 'FIELDS:'
+
+  # Cleanup
+  kubectl delete crd mock-resources.test.com
+
+  set +o nounset
+  set +o errexit
+}

test/cmd/legacy-script.sh

@@ -526,6 +526,14 @@ runTests() {
     record_command run_ambiguous_shortname_tests
   fi
 
+  ################
+  # Explain crd  #
+  ################
+
+  if kube::test::if_supports_resource "${customresourcedefinitions}" ; then
+    record_command run_explain_crd_with_additional_properties_tests
+  fi
+
   #########################
   # Assert categories     #
   #########################