etcd-io/etcd · error

unexpected countOnly in delete

Error message

unexpected countOnly in delete

What it means

OpDelete rejects WithCountOnly. countOnly asks the server to return just the number of matching keys for a range query; a delete response already returns only the deleted count, so the flag is redundant and unsupported. When applyOpts sets ret.countOnly, the constructor panics with "unexpected countOnly in delete".

Solutions

1. For a pre-delete count, use cli.Get(ctx, prefix, clientv3.WithPrefix(), clientv3.WithCountOnly()) and read resp.Count — a Get, not a Delete.
2. Remove WithCountOnly from Delete calls; resp.Deleted in the DeleteResponse already carries the count.

Example fix

// before (trying to preview delete impact)
resp, err := cli.Delete(ctx, "/stale/", clientv3.WithPrefix(), clientv3.WithCountOnly()) // panics

// after
gr, err := cli.Get(ctx, "/stale/", clientv3.WithPrefix(), clientv3.WithCountOnly())
fmt.Println("will delete", gr.Count, "keys")

When it happens

Trigger: clientv3.OpDelete("/k/", clientv3.WithPrefix(), clientv3.WithCountOnly()); 'check how many would be deleted' probes that reuse the delete call with countOnly instead of a Get.

Common situations: Pre-flight checks before bulk deletes implemented by copying the delete call and adding WithCountOnly; option forwarding from an existence-count routine.

Related errors

• unexpected create revision filter in delete
• unexpected createdNotify in delete
• unexpected filter in delete
• unexpected lease in delete
• unexpected limit in delete

AI-assisted analysis of etcd-io/etcd@f744d457f4 (2026-08-15). Data as JSON: /api/errors/be020e0b48d74a10. Report an issue: GitHub.

Appendix: source

Thrown at client/v3/op.go:287

	// WithPrefix and WithFromKey are not supported together
	if IsOptsWithPrefix(opts) && IsOptsWithFromKey(opts) {
		panic("`WithPrefix` and `WithFromKey` cannot be set at the same time, choose one")
	}
	ret := Op{t: tDeleteRange, key: []byte(key)}
	ret.applyOpts(opts)
	switch {
	case ret.leaseID != 0:
		panic("unexpected lease in delete")
	case ret.limit != 0:
		panic("unexpected limit in delete")
	case ret.rev != 0:
		panic("unexpected revision in delete")
	case ret.sort != nil:
		panic("unexpected sort in delete")
	case ret.serializable:
		panic("unexpected serializable in delete")
	case ret.countOnly:
		panic("unexpected countOnly in delete")
	case ret.minModRev != 0, ret.maxModRev != 0:
		panic("unexpected mod revision filter in delete")
	case ret.minCreateRev != 0, ret.maxCreateRev != 0:
		panic("unexpected create revision filter in delete")
	case ret.filterDelete, ret.filterPut:
		panic("unexpected filter in delete")
	case ret.createdNotify:
		panic("unexpected createdNotify in delete")
	}
	return ret
}

// OpPut returns "put" operation based on given key-value and operation options.
func OpPut(key, val string, opts ...OpOption) Op {
	ret := Op{t: tPut, key: []byte(key), val: []byte(val)}
	ret.applyOpts(opts)
	switch {
	case ret.end != nil:

View on GitHub (pinned to f744d457f4)