fix(no-anti-affinity): support topology spread constraints

[mwozniakk]

Fixes #894.

Summary:

• Treats matching topologySpreadConstraints as satisfying the no-anti-affinity check.
• Requires the spread constraint to match the configured topology key and pod template labels.
• Adds unit tests for matching and non-matching topology spread constraints.
• Updates generated check docs.

Testing:

• go test ./pkg/templates/antiaffinity ./pkg/builtinchecks
• go test ./...

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Central YAML (base), Organization UI (inherited)

Review profile: CHILL

Plan: Enterprise

Run ID: 6ab1a58e-0335-451e-8623-f2f27ef78a5c

📥 Commits

Reviewing files that changed from the base of the PR and between 20f4ba9 and f63de09.

📒 Files selected for processing (1)

• pkg/templates/antiaffinity/template_test.go

🚧 Files skipped from review as they are similar to previous changes (1)

• pkg/templates/antiaffinity/template_test.go

---

📝 Walkthrough

Summary by CodeRabbit

• Bug Fixes
  • Anti-affinity validation now short-circuits when a workload’s topologySpreadConstraints already match the configured criteria, reducing false warnings.
• Documentation
  • Updated the no-anti-affinity remediation and description to include topologySpreadConstraints alongside podAntiAffinity, with clearer labelSelector and kubernetes.io/hostname examples.

Walkthrough

The anti-affinity checker now treats matching topologySpreadConstraints as sufficient, updates the builtin check text to mention that alternative, and adds tests covering matching, mismatching, and invalid selector cases.

Changes

TopologySpreadConstraints support

Layer / File(s)	Summary
Core validation logic and early-return guard pkg/templates/antiaffinity/template.go	Adds topologySpreadConstraintsMatchAgainstNodes and uses it to return no diagnostics when a pod template’s spread constraints already satisfy the topology-key and label-match checks.
Test coverage and check documentation pkg/templates/antiaffinity/template_test.go, pkg/builtinchecks/yamls/no-anti-affinity.yaml	Adds topology-spread deployment helpers and validation coverage across topology-key, selector, and unsatisfiable-policy cases, and updates the builtin check description and remediation to include topologySpreadConstraints.

Estimated code review effort: 2 (Simple) | ~12 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title is concise and accurately summarizes the main change: adding topology spread constraint support to the no-anti-affinity check.
Description check	✅ Passed	The description is clearly related to the change and matches the implementation and tests.
Linked Issues check	✅ Passed	The change addresses #894 by accepting matching topologySpreadConstraints as satisfying the no-anti-affinity rule.
Out of Scope Changes check	✅ Passed	The modified docs, validation logic, and tests all support the stated topologySpreadConstraints feature.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@pkg/templates/antiaffinity/template_test.go`:
- Around line 135-152: Add a focused test covering TopologySpreadConstraints
with WhenUnsatisfiable set to ScheduleAnyway in the AntiAffinityTestSuite
helpers and related deployment setup. The current
addDeploymentWithTopologySpreadConstraint path only exercises DoNotSchedule, so
extend the test suite with a case that uses ScheduleAnyway and asserts the
intended behavior in topologySpreadConstraintsMatchAgainstNodes and the
deployment validation flow. Use the existing
addDeploymentWithTopologySpreadConstraint, addDeploymentWithReplicas, and
ctx.ModifyDeployment helpers to keep the new case aligned with the current test
structure.

In `@pkg/templates/antiaffinity/template.go`:
- Around line 115-127: The helper topologySpreadConstraintsMatchAgainstNodes
currently treats every matching TopologySpreadConstraint as enforcing spread,
including soft preferences. Update this function to only return true when the
constraint’s WhenUnsatisfiable is DoNotSchedule, in addition to the existing
topologyKeyMatcher and labelSelector match. Keep the LabelSelectorAsSelector
error handling as-is, and add the new guard directly in the conditional so
ScheduleAnyway constraints are ignored.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Central YAML (base), Organization UI (inherited)

Review profile: CHILL

Plan: Enterprise

Run ID: 8c1c8f5e-a8f2-43c2-a656-48d1c2fa212a

📥 Commits

Reviewing files that changed from the base of the PR and between 1521d3a and 20f4ba9.

⛔ Files ignored due to path filters (1)

• docs/generated/checks.md is excluded by !**/generated/**

📒 Files selected for processing (3)

• pkg/builtinchecks/yamls/no-anti-affinity.yaml
• pkg/templates/antiaffinity/template.go
• pkg/templates/antiaffinity/template_test.go

[codecov]

Codecov Report

❌ Patch coverage is 81.81818% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 31.42%. Comparing base (dbd7529) to head (20f4ba9).
⚠️ Report is 332 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/templates/antiaffinity/template.go	81.81%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1224       +/-   ##
===========================================
- Coverage   62.36%   31.42%   -30.94%     
===========================================
  Files         197      239       +42     
  Lines        4854     6572     +1718     
===========================================
- Hits         3027     2065      -962     
- Misses       1439     4329     +2890     
+ Partials      388      178      -210     

Flag	Coverage Δ
unit	31.42% <81.81%> (-30.94%)	⬇️

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