fix(telemetry): the Class A lists could silently shrink (backend#2341)

[LukasWodka]

Closes tracebloc/backend#2341 — Bugbot High on the #789 promotion, holding client out of the 22 Aug staging hop. Fixed on develop as the ticket asks, so #789 can be re-cut without re-rolling its review.

The concern is real and is fixed. The stated mechanism is not what happens, and the real one is worse — so both are recorded rather than the ticket being implemented as written.

What the finding said vs what happens

a partial telemetryCollector map under --reuse-values leaves the lists absent, include renders empty, and the DaemonSet stays Ready collecting nothing

Constructed rather than reasoned about:

helm template … -f <partial map> -> all 4 globs
helm template … --set-json '{"enabled":true}' -> all 4 globs

Helm coalesces chart defaults at render time, so an absent key comes back from values.yaml. The --reuse-values shape does not reproduce this.

The reachable route is an explicit null

--set telemetryCollector.classAContainers=null -> include drops to 1 of 4

helm deletes a key set to null, and a deleted key does not coalesce back. The schema's minItems: 1 rejects an empty list and says nothing about an absent one.

And the quiet case is one list, not both — which inverts the severity

• Nulling both empties the include, and filelog refuses to start on that. Loud.
• Nulling one leaves a perfectly valid config with a shorter list: the Collector starts, reports Ready, and silently omits three of the four Class A containers. This is the healthy-but-blind failure, and it's the case the ticket's framing doesn't reach.

Fixed in two layers, each driven through the path that reaches it

values.schema.json marks both lists required, so a null fails validation. Verified this does not break the three documented paths — a null whole map (the --reuse-values-from-an-older-release case the schema's own description calls out), an absent map, and an explicitly disabled Collector all still validate and render.

The template fails closed on each list separately. Not belt-and-braces: helm has --skip-schema-validation, so this is the layer that can't be bypassed, and the guard drives exactly that flag.

My first version of the template guard missed the case that matters

It checked only that the combined include list was non-empty — which fires on total blindness (the loud one) and passed the one-list case that renders short and silent. Caught by testing it rather than reading it. The guard now checks each list.

Tests

The shrink cases go in collector-class-a-agreement.sh, which already owns this concern, rather than a new file:

 ok schema rejects a null classAContainers
ok schema rejects a null classANodeAgentContainers
ok template refuses a null classAContainers (schema skipped)
ok template refuses a null classANodeAgentContainers (schema skipped)
ok a partial map still coalesces all 4 Class A globs

That last one is a control, pinning the behaviour the finding assumed was broken — so a change that really did break coalescing is caught.

Mutation	Result
schema required removed	KILLED — refused, but for the wrong reason
per-list template fails removed	KILLED — the render succeeded
include reads a non-existent key	KILLED — 1 glob, want 4

Test plan

• helm unittest . — 538 passed
• make drift — 13/13 guards green
• make check — parse, shellcheck -S warning, helm-lint, helm-vocab
• Mutation matrix above, anchors asserted applied
• All under KUBECONFIG=/nonexistent — no dependence on ambient kube state
• Re-cut the promotion: stage=prepare recut=true recut_repos=client

🤖 Generated with Claude Code

---

Note

Medium Risk
Changes Helm schema and fail-closed template logic for telemetry log collection. Wrong guards could block upgrades or still allow a Ready Collector that silently drops Class A logs.

Overview
Stops the edge Collector from rendering a healthy-but-blind config when Helm deletes a Class A list set to null (backend#2341). Nulling one list used to leave a valid shorter filelog include: Ready, and missing most Class A containers.

values.schema.json now requires classAContainers and classANodeAgentContainers. The ConfigMap template fails closed on each list (not only the combined include), including under --skip-schema-validation. Chart bump to 1.9.61.

Tests pin both layers plus the control that a partial telemetryCollector map still coalesces all four globs.

^{Reviewed by Cursor Bugbot for commit 020b270. Bugbot is set up for automated code reviews on this repo. Configure here.}

[LukasWodka]

bugbot run

[cursor]

✅ Bugbot reviewed your changes and found no new issues!

Comment @cursor review or bugbot run to trigger another review on this PR

^{Reviewed by Cursor Bugbot for commit 020b270. Configure here.}

[LukasWodka]

/fr-pass