fix: do not NPE when adding a finalizer to a resource deleted mid-retry

[csviri]

conflictRetryingPatchPrimary / conflictRetryingPatch re-read the
resource from the API server after a 409 or 422 and then re-evaluate the
precondition:

resource = operation.inNamespace(ns).withName(name).get();

get() returns null if the resource was deleted in the meantime, so the
next iteration calls the precondition with null. removeFinalizer
anticipates this:

r -> {
  if (r == null) {
    log.warn("Cannot remove finalizer since resource not exists.");
    return false;
  }
  return r.hasFinalizer(finalizerName);
}

but addFinalizer passes r -> !r.hasFinalizer(finalizerName), which
throws a NullPointerException instead of exiting cleanly.

Gives addFinalizer the same null guard, in both ResourceOperations and
the deprecated PrimaryUpdateAndCacheUtils.

No test is added: reaching the retry path requires stubbing the client to
answer 409/422 and then 404 through the whole fabric8 DSL chain, which the
existing unit tests are not set up for.

Part of #3517

[Copilot]

Pull request overview

Prevents a NullPointerException when addFinalizer is executed through the conflict-retry patch path and the primary resource is deleted between retries (i.e., the re-read get() returns null). This makes addFinalizer behave consistently with existing removeFinalizer handling in ResourceOperations.

Changes:

• Add a null-guard to the addFinalizer precondition in ResourceOperations to avoid dereferencing a deleted resource during retry.
• Add the same null-guard to the deprecated PrimaryUpdateAndCacheUtils.addFinalizer retry precondition (and log when the resource is gone).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/reconciler/ResourceOperations.java	Adds null-guarded precondition for addFinalizer during conflict-retry patch.
operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/reconciler/PrimaryUpdateAndCacheUtils.java	Adds null-guarded precondition for deprecated addFinalizer during conflict-retry patch.