fix(k8s,service): Hide fields first before creating diffs (#915) (#962)

This is a backport of PR #915 as merged into main (6a0635a).
SUMMARY

By hiding fields first before creating a diff hidden fields will not be shown in the resulting diffs and therefore will also not trigger the changed condition.
The issue can only be reproduced when a mutating webhook changes the object while the kubernetes.core.k8s module is working with it.

kubevirt/kubevirt.core#145
ISSUE TYPE


Bugfix Pull Request

COMPONENT NAME

kubernetes.core.module_utils.k8s.service
ADDITIONAL INFORMATION


Run kubernetes.core.k8s and create object with hidden fields. After run kubernetes.core.k8s again and let a webhook mutate the object that the module is working with. The module should return with changed: no.

Reviewed-by: Bianca Henderson <beeankha@gmail.com>

changelogs/fragments/20250428-k8s-service-hide-fields-first.yaml

@@ -0,0 +1,3 @@
+---
+bugfixes:
+  - module_utils/k8s/service - hide fields first before creating diffs (https://github.com/ansible-collections/kubernetes.core/pull/915).

plugins/module_utils/k8s/service.py

@@ -498,8 +498,8 @@ def diff_objects(
     if not diff:
         return True, result
 
-    result["before"] = diff[0]
-    result["after"] = diff[1]
+    result["before"] = hide_fields(diff[0], hidden_fields)
+    result["after"] = hide_fields(diff[1], hidden_fields)
 
     if list(result["after"].keys()) == ["metadata"] and list(
         result["before"].keys()
@@ -512,9 +512,6 @@ def diff_objects(
         ).issubset(ignored_keys):
             return True, result
 
-    result["before"] = hide_fields(result["before"], hidden_fields)
-    result["after"] = hide_fields(result["after"], hidden_fields)
-
     return False, result
 
 

tests/integration/targets/k8s_hide_fields/tasks/main.yml

@@ -58,7 +58,7 @@
           - "'managedFields' not in hf4.resources[0]['metadata']"
 
 
-    - name: Hiding a changed field should still result in a change
+    - name: Hiding a changed field should not result in a change
       k8s:
         definition: "{{ hide_fields_base_configmap | combine({'data':{'hello':'different'}}) }}"
         hidden_fields:
@@ -67,10 +67,10 @@
       register: hf5
       diff: true
 
-    - name: Ensure that hidden changed field changed
+    - name: Ensure that hidden changed field not changed
       assert:
         that:
-          - hf5.changed
+          - not hf5.changed
 
     - name: Apply works with hidden fields
       k8s: