Fix the finalizer writes on Modules and their plugin Pods

[TomerNewman]

metadata.finalizers is a list, and a merge patch sends a list whole. A write computed from a read that predates another controller's entry therefore removes that entry along with its own. Both writers of ModuleFinalizer, and the one that takes NodeLabelerFinalizer off a plugin Pod, now carry the resourceVersion they read, so a stale write fails rather than lands.

The Pod node label reconciler also treated a Node that had already gone as an error. Its own finalizer then stayed on the Pod for good, and so did anything waiting for that Pod. A Node that is not there carries no label, so that case is done rather than failed.

fix #1931

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/cc @yevgeny-shnaidman
/assign @yevgeny-shnaidman

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📥 Commits

Reviewing files that changed from the base of the PR and between 436d4da and 2d3386d.

📒 Files selected for processing (4)

• internal/controllers/module_reconciler.go
• internal/controllers/module_reconciler_test.go
• internal/controllers/pod_node_label_reconciler.go
• internal/controllers/pod_node_label_reconciler_test.go

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Summary by CodeRabbit

• Bug Fixes
  • Improved reliability when multiple controllers update module or pod finalizers concurrently, preserving changes made by other controllers.
  • Pod label reconciliation now completes successfully when the associated node has already been deleted.
  • Finalizer updates now preserve unrelated finalizers and current resource versions, reducing the risk of stale updates overwriting newer changes.

Walkthrough

Module and pod finalizer patches now include optimistic locking. Pod label deletion treats missing nodes as successful. Tests verify resource-version handling, foreign finalizer preservation, and node read failures.

Changes

Controller reconciliation

Layer / File(s)	Summary
Module finalizer locking internal/controllers/module_reconciler.go, internal/controllers/module_reconciler_test.go	Module finalizer addition and removal use optimistic-lock merge patches. Tests verify resource version "7" and preservation of another finalizer.
Pod node and finalizer reconciliation internal/controllers/pod_node_label_reconciler.go, internal/controllers/pod_node_label_reconciler_test.go	Missing nodes no longer fail label deletion. Other node read errors remain failures. Pod finalizer removal uses optimistic locking and preserves unrelated finalizers.

Priority: ⬇️ Low

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

Change: Bug fix

Merge Risk: ⚪ Minimal · up to 2d338

The change prevents stale finalizer writes and allows cleanup after node deletion; the supplied coverage supports merging with normal checks.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 4…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly summarizes the changes to finalizer writes on Modules and plugin Pods.
Description check	✅ Passed	The description accurately explains optimistic locking for finalizer writes and handling of missing Nodes.

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[TomerNewman]

/retest