fix: checking for null to avoid NPE with SSA matching (#3037)

closes: #3034

Signed-off-by: Steve Hawkins <shawkins@redhat.com>

Author: shawkins

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/dependent/kubernetes/SSABasedGenericKubernetesResourceMatcher.java

@@ -320,6 +320,10 @@ private static void handleListKeyEntrySet(
     result.put(keyInActual, valueList);
     var actualValueList = (List<Map<String, Object>>) actualMap.get(keyInActual);
 
+    if (actualValueList == null) {
+      return;
+    }
+
     var targetValuesByIndex = new TreeMap<Integer, Map<String, Object>>();
     var managedEntryByIndex = new HashMap<Integer, Map<String, Object>>();
 
@@ -396,6 +400,11 @@ private static void handleSetValues(
         continue;
       }
       var values = (List<?>) actualMap.get(keyInActual);
+
+      if (values == null || values.isEmpty()) {
+        continue;
+      }
+
       var targetClass = (values.get(0) instanceof Map) ? null : values.get(0).getClass();
       var value = parseKeyValue(keyWithoutPrefix(valueEntry.getKey()), targetClass, objectMapper);
       valueList.add(value);

operator-framework-core/src/test/java/io/javaoperatorsdk/operator/processing/dependent/kubernetes/SSABasedGenericKubernetesResourceMatcherTest.java

@@ -49,6 +49,29 @@ void setup() {
     when(mockedContext.getControllerConfiguration()).thenReturn(controllerConfiguration);
   }
 
+  @Test
+  void statefulSetWithMissingManagedField() {
+    var actual = loadResource("statefulset-with-managed-fields-missing.yaml", StatefulSet.class);
+    var desired =
+        actual
+            .edit()
+            .editMetadata()
+            .withManagedFields(List.of())
+            .endMetadata()
+            .editSpec()
+            .editTemplate()
+            .editSpec()
+            .editFirstContainer()
+            .withImage("new")
+            .endContainer()
+            .endSpec()
+            .endTemplate()
+            .endSpec()
+            .build();
+
+    assertThat(matcher.matches(actual, desired, mockedContext)).isFalse();
+  }
+
   @Test
   void noMatchWhenNoMatchingController() {
     var desired = loadResource("nginx-deployment.yaml", Deployment.class);