fix: use DeletionHandlingMetaNamespaceKeyFunc in DeleteFunc for tombstone support

[Copilot]

DeleteFunc was calling cache.MetaNamespaceKeyFunc(obj) after tombstone extraction, but when obj is a cache.DeletedFinalStateUnknown, this call errors and the delete event is silently dropped — a common case when the informer misses a delete during a resync.

Change

Replace with cache.DeletionHandlingMetaNamespaceKeyFunc(obj), which unwraps tombstones internally before computing the key:

// Before
key, err := cache.MetaNamespaceKeyFunc(obj)

// After
key, err := cache.DeletionHandlingMetaNamespaceKeyFunc(obj)

This ensures delete events are reliably enqueued regardless of whether obj is a live object or a tombstone.

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[Copilot]

Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• 10.244.0.2
  • Triggering command: /usr/bin/kubelet /usr/bin/kubelet --bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --kubeconfig=/etc/kubernetes/kubelet.conf --config=/var/lib/kubelet/config.yaml --node-ip=172.18.0.2 --node-labels= --provider-id=kind://docker/kind/kind-control-plane --runtime-cgroups=/system.slice/containerd.service -p 362ed76be0fb8547ac103d984da01135dc3/2df1b4ebfb67ffaf232cdda5db341d7de613bdca38f0db51�� mpile rg/toolchain@v0./run/systemd/generator.late ortc�� oller/... stmain.go rg/toolchain@v0./tmp/pty1124488072/pty.sock -p github.com/githu/tmp/kubelet-detect-safe-umount1660551564 t rg/toolchain@v0.0.1-go1.25.4.lin{{json .}} (packet block)
• 10.244.0.4
  • Triggering command: /usr/bin/kubelet /usr/bin/kubelet --bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --kubeconfig=/etc/kubernetes/kubelet.conf --config=/var/lib/kubelet/config.yaml --node-ip=172.18.0.2 --node-labels= --provider-id=kind://docker/kind/kind-control-plane --runtime-cgroups=/system.slice/containerd.service -p 362ed76be0fb8547ac103d984da01135dc3/2df1b4ebfb67ffaf232cdda5db341d7de613bdca38f0db51�� mpile rg/toolchain@v0./run/systemd/generator.late ortc�� oller/... stmain.go rg/toolchain@v0./tmp/pty1124488072/pty.sock -p github.com/githu/tmp/kubelet-detect-safe-umount1660551564 t rg/toolchain@v0.0.1-go1.25.4.lin{{json .}} (packet block)
• 5559030534559597294.4248727371591342039
  • Triggering command: /coredns /coredns -conf /etc/coredns/Corefile 961923f91426355d-trimpath ker/�� 4c3ed0e3:interna-p t .cfg -c=4 -nolocalimports t pkg/mod/golang.o-I -uns�� -unreachable=fal-t t by/91d04b7a5ddd0-m go t.go t pkg/mod/golang.o-m (dns block)
• 6270441476402540855.9136771553807258282
  • Triggering command: /coredns /coredns -conf /etc/coredns/Corefile pkg/mod/golang.org/toolchain@v0.--detach -uns�� -unreachable=false t pkg/mod/golang.org/toolchain@v0.0.1-go1.25.4.linux-amd64/pkg/tool/linux_amd64/vet -c=4 -nolocalimports t pkg/mod/golang.org/toolchain@v0./var/run/docker/runtime-runc/moby 6abc�� -bool t rs/rpc-pipefs-generator -errorsas -ifaceassert l/linux_amd64/vero,bind rs/rpc-pipefs-ge/run/containerd/io.containerd.runtime.v2.task/k8s.io/2d72ec21c84a46a28d30ba449feffefccc1e02d6dbb7305d5bf69db0e47be44a/rootfs/product_uuid (dns block)
• 6901084433189853732.4502597976292703045
  • Triggering command: /coredns /coredns -conf /etc/coredns/Corefile l/linux_amd64/asm ker/�� os/signal t .cfg -I /tmp/go-build220-w oduct_uuid 464bc37fac710727-I -uns�� -unreachable=fal-t eb150b8272c5ead0filter eb150b8272c5ead0-m by/91d04b7a5ddd0chmod GOAMD64_v1 t pkg/mod/golang.o-m (dns block)
• 8063012640336197325.7990332815844875937
  • Triggering command: /coredns /coredns -conf /etc/coredns/Corefile pkg/mod/golang.org/toolchain@v0.--log -uns�� -unreachable=false t pkg/mod/golang.org/toolchain@v0.--systemd-cgroup 1/csidriver.go c0888bfba1f23a8c362ed76be0fb8547ac103d984da01135dc3/86fa02eddd39e5f88309407c968e4282�� (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

[Copilot]

Pull request overview

This PR fixes Kubernetes informer delete-event handling by ensuring keys are generated correctly even when the delete event arrives as a tombstone (cache.DeletedFinalStateUnknown), preventing delete events from being dropped during resync/missed-watch scenarios.

Changes:

• Switch DeleteFunc key generation from cache.MetaNamespaceKeyFunc to cache.DeletionHandlingMetaNamespaceKeyFunc to properly handle tombstones.

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