[albertompe]

Redkey Robin v0.2.1

This patch release hardens Robin's handling of persistent clusters that retain
their PVCs (deletePVC: false) across upgrades and scaling, adds a
scale-to-zero lookahead, exposes build/version information, and refreshes
the toolchain and dependencies. There are no CRD changes; it is a drop-in
replacement for v0.2.0.

Highlights

• Scale-to-zero lookahead. When a later pending RedkeyConfig targets
  primaries: 0, Robin jumps straight to the last such config and marks the
  intermediate ones as Superseded, regardless of skipIfSuperseded. A wedged
  InProgress config (e.g. an upgrade to an invalid image) is also superseded when
  scaling to zero discards the cluster data (ephemeral cluster or
  deletePVC: true); storage clusters that keep their PVCs wait for the
  InProgress operation to finish so they can be restored when scaling back up
  ([Feature] Fast-path scale-to-zero: supersede intermediate pending configs #41, partially mitigates [Bug] Unrecoverable deadlock when an in-progress config cannot complete #42).
• Build info. New redkey_robin_build_info gauge (labels version and
  go_version), a --version flag, the version in the startup log, and
  redkey-robin/<version> as the Kubernetes client User-Agent.

Fixes

• Repeated Rolling N+1 upgrades on persistent clusters (deletePVC: false) no
  longer stall forever: stale extra (N+1) pods remounting retained PVCs are reset
  to pristine empty masters before being met (clusters already stuck recover), and
  the extra pods are left pristine at the end of every upgrade.
• Scale-up of persistent clusters resets re-created pods that remount a PVC
  retained by an earlier scale-down instead of integrating them under their stale
  identity.
• Recycling a drained node during a Rolling N+1 upgrade no longer lets the
  restarted pod reload stale keys from the AOF and claim their slots.
• Slot range parsing hardened: slots outside 0-16383 are rejected,
  CountSlotsFromRanges ignores malformed tokens, and unparseable slot entries are
  treated as ownership to protect slot owners from CLUSTER FORGET ([Bug] Harden slot range parsing in Robin against out-of-range and malformed tokens #62).
• Version injection: the image build's -ldflags -X main.version was a silent
  no-op; the version is now injected (also by make build/make run), with plain
  go build falling back to dev.
• Security: golang.org/x/net bumped to v0.61.0 (GO-2026-6603, GO-2026-6610,
  GO-2026-6611, GO-2026-6612, GO-2026-6617).

Packaging & tooling

• Go 1.27.2, controller-runtime v0.25.2, k8s.io/* v0.37.1, go-redis v9.23.0 and
  the remaining direct dependencies at their latest versions.
• Bundled redis-cli bumped to 8.10.2.
• golangci-lint v2.14.0 with a .golangci.yml aligned with Redkey Operator;
  envtest pinned to Kubernetes 1.33.
• Go native fuzz tests for the Redis output parsers (make fuzz) and integration
  specs against real redis-server processes (make redis, label redis).
• Removed the unused redis.ParseOpenSlots helper.

Compatibility

• No CRD changes. Works with Redkey Operator v0.2.x; Redkey Operator v0.2.1 is
  recommended (its Grafana dashboard shows the Robin version from
  redkey_robin_build_info).