fix: preserve subject and source on GenericChange findings

[Sanjays2402]

Closes #2044

K8sBaseChangeEvent.create_default_finding() built a Finding with only a title and aggregation_key, so finding.subject stayed at the ExecutionBaseEvent default (namespace None) and source stayed NONE. Sink routing reads finding.attribute_map["namespace"], which derives from subject.namespace, so Kubernetes change notifications were routed as namespace "None" rather than the resource's real namespace.

The event already exposes get_subject()/get_source() — this passes them through, matching what PrometheusKubernetesAlert.create_default_finding() already does. The new test in tests/test_change_filters.py fails on master (assert None == 'default') and passes with the fix.

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Walkthrough

Kubernetes default findings now include the event subject and source. Tests cover aggregation key, namespace/name preservation, Kubernetes API server source, and corresponding attribute map values.

Changes

Kubernetes finding metadata

Layer / File(s)	Summary
Default finding metadata and regression coverage src/robusta/integrations/kubernetes/base_event.py, tests/test_change_filters.py	create_default_finding() now sets the event subject and source. Tests verify the aggregation key, subject fields, source, and namespace/name attributes.

Estimated code review effort: 2 (Simple) | ~10 minutes

Severity of issue fixed: Medium

Merge Risk: ⚪ Minimal · up to 31286

Kubernetes GenericChange findings now retain resource subject metadata and Kubernetes API-server source, preserving namespace-aware routing and grouping. Regression coverage accompanies the change, with no remaining merge-blocking risk identified.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 3 functions across 1 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main change: preserving subject and source metadata on GenericChange findings.
Description check	✅ Passed	The description directly explains the Kubernetes finding metadata bug, its routing impact, the fix, and the regression test.
Linked Issues check	✅ Passed	The implementation adds get_subject() and get_source() to default Kubernetes findings. The regression test verifies the required subject metadata and KUBERNETES_API_SERVER source for issue #2044.
Out of Scope Changes check	✅ Passed	The changes are limited to the issue fix and related regression coverage. The import cleanup and added metadata assertions are in scope.

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Actionable comments posted: 2

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Verify each finding against current code. Fix only still-valid issues, skip the
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Inline comments:
In `@tests/test_change_filters.py`:
- Around line 99-108: Extend test_default_finding_keeps_subject_and_source to
assert that finding.subject.labels and finding.subject.annotations match the
corresponding labels and annotations in the event fixture metadata, alongside
the existing namespace and name checks.
- Line 17: Remove the unused DEFAULT_CHANGE_INCLUDE import from the imports in
tests/test_change_filters.py, leaving the required DEFAULT_CHANGE_IGNORE import
and other dependencies unchanged.

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📒 Files selected for processing (2)

• src/robusta/integrations/kubernetes/base_event.py
• tests/test_change_filters.py

[Sanjays2402]

Thanks for the review — both points addressed in 312869f:

• Dropped the unused DEFAULT_CHANGE_INCLUDE import from tests/test_change_filters.py.
• Extended test_default_finding_keeps_subject_and_source to assert finding.subject.labels == {"app": "xxx"} and finding.subject.annotations == {"deployment.kubernetes.io/revision": "24"} against the fixture metadata, so a regression in the full subject is caught.