fix: checking for null to avoid NPE with SSA matching

[shawkins]

closes: #3034

[Copilot]

Pull Request Overview

This PR fixes a NullPointerException in the SSA (Server-Side Apply) based Kubernetes resource matcher when processing managed fields that reference collections that are null or missing in the actual resource. The fix adds null checks before dereferencing list values in two key methods.

Key changes:

• Added null check in handleListKeyEntrySet to prevent NPE when actualValueList is null
• Added null check in handleSetValues to prevent NPE when values is null
• Added test case with a StatefulSet containing managed fields that reference missing values

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
SSABasedGenericKubernetesResourceMatcher.java	Added null checks in handleListKeyEntrySet and handleSetValues methods to prevent NPE when referenced collections are missing
SSABasedGenericKubernetesResourceMatcherTest.java	Added test case statefulSetWithMissingManagedField to verify matching works when managed fields reference missing values
statefulset-with-managed-fields-missing.yaml	Added test resource file containing a StatefulSet with managed fields that reference potentially missing values

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[Copilot]

After adding the null check for values at line 404-406, accessing values.get(0) at line 408 can still throw an IndexOutOfBoundsException if the list is empty. Consider adding a check for values.isEmpty() before accessing the first element.

Suggested change

	}
	}
	if (values.isEmpty()) {
	continue;
	}