fix(deploy): retry the Flux parent fence when controller churn breaks its CAS - #3882
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… its CAS The GHCR bridge fences the image-verification policy handoff with an optimistic-concurrency JSON patch on the parent Flux Kustomization: test /metadata/resourceVersion and /metadata/uid, then add the owner annotation and spec.suspend. That object's status is rewritten continuously by its own controller, so its resourceVersion moves on its own and the test is lost to nothing but ordinary churn -- and on a serialized merge queue it is lost exactly when the queue is busiest. A lost test killed the whole production deploy and evicted the PR. Retry the read->patch cycle instead, bounded at 5 attempts with the existing sync interval as backoff, and only when the re-read proves the rejection was contention: the resourceVersion demonstrably moved, the object is the same UID, is still well-formed, is unfenced by anyone, and is not suspended. Every other rejection -- a permission denial, a validation error, anything at an unchanged resourceVersion -- still fails closed on the first attempt, and a foreign owner found by the re-read is refused on sight with the same wording the pre-acquisition check uses rather than retried against. The ambiguous-response adoption path is unchanged and still takes precedence, so EXIT cleanup continues to own a fence whose patch response was lost. Fixes #3046 Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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🔇 Additional comments (3)
📝 WalkthroughWalkthroughThe parent Flux policy handoff now retries compare-and-swap failures caused by resourceVersion changes. It re-reads the parent, checks ownership and claim preconditions, and retries up to five attempts. Foreign ownership, unchanged resourceVersion, lost leases, and exhausted retries still fail closed. The fake Kubernetes implementation simulates controller churn and reread failures. Rollout tests cover successful retry, foreign-owner refusal, retry exhaustion, and diagnostic handling. Priority: ➖ Normal Severity of issue fixed: Medium Merge Risk: ⚪ Minimal · up to The Flux fence now handles controller contention with bounded retries while retaining fail-closed ownership and exhaustion behavior. No unresolved merge-readiness risk remains. 🚥 Pre-merge checks | ✅ 4 | ❌ 1❌ Failed checks (1 warning)
✅ Passed checks (4 passed)
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Actionable comments posted: 1
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Inline comments:
In `@scripts/refresh-flux-ghcr-auth.sh`:
- Around line 4812-4816: Update the re-read diagnostic handling around
reread_error_file so an empty file is treated as a copy failure before cat
succeeds. Ensure flux_policy_parent_result_file receives the deterministic
fallback message when the diagnostic is empty or cannot be read, while
preserving non-empty diagnostics.
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scripts/refresh-flux-ghcr-auth.shscripts/tests/refresh-flux-ghcr-auth/fake_kubectl_test.goscripts/tests/refresh-flux-ghcr-auth/rollout_convergence_test.go
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🧠 Learnings (1)
📚 Learning: 2026-08-10T13:01:12.782Z
Learnt from: devantler
Repo: devantler-tech/platform PR: 3057
File: .github/workflows/ci.yaml:622-659
Timestamp: 2026-08-10T13:01:12.782Z
Learning: Repository shell tests and scripts must remain compatible with macOS Bash 3.2. Do not use Bash 4+ features such as `mapfile`; use portable constructs, such as a `while IFS= read -r` loop, instead.
Applied to files:
scripts/refresh-flux-ghcr-auth.sh
🔇 Additional comments (2)
scripts/tests/refresh-flux-ghcr-auth/fake_kubectl_test.go (1)
511-542: LGTM!scripts/tests/refresh-flux-ghcr-auth/rollout_convergence_test.go (1)
1333-1438: LGTM!
A parent re-read that exits non-zero without writing stderr leaves the diagnostic file at zero bytes. Copying it then succeeds while the redirection has already truncated the result file, and emit_safe_operation_output skips an empty file, so the operator is told the fence could not be taken but never why. Guard on the file being non-empty as well as on the copy succeeding, and cover both directions: one test drives a silent failure and asserts the fallback line is emitted, the other drives a failure carrying stderr and asserts that text survives verbatim rather than being replaced by the fallback. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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Readiness — exercised, not just builtTried and evaluated as a user, at head Baseline: the whole fence/CAS surface is green — 72 tests pass, including the three this PR A passing test proves nothing on its own, so I ablated the fix — dropping the claim budget
The ablated failure reproduces the exact production symptom this PR was opened for: That is the deploy death that evicted #3878 from the merge queue. So the retry is doing the Script restored afterwards; Review: |
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Why
A production deploy can die — and evict the PR from the merge queue — because of nothing more than Flux being busy. The GHCR credential bridge briefly pauses the parent Flux reconciliation, and it claims that pause with a compare-and-swap against a value Flux's own controller rewrites continuously. When the two collide, the whole deploy fails.
It is worst exactly when it costs most: the merge queue builds the next PR seconds after the previous one merges, so the collision is likeliest when throughput matters. It happened again tonight, evicting #3878.
What
Retry the claim, bounded, when the re-read proves the collision was ordinary contention. A genuine competing transaction is still refused immediately — and now says so in words that distinguish it from contention — and every other kind of rejection still fails on the first attempt, so nothing that should stop a deploy stops being able to.
Fixes #3046