Function peerChangeDiff

control/controlclient/map.go:979–1194

peerChangeDiff returns the difference from 'was' to 'n', if possible. It returns (nil, true) if the fields were identical.

(was tailcfg.NodeView, n *tailcfg.Node, onFalse func(string))

//
// It returns (nil, true) if the fields were identical.
func peerChangeDiff(was tailcfg.NodeView, n *tailcfg.Node, onFalse func(string)) (_ *tailcfg.PeerChange, ok bool) {
	if onFalse == nil {
		onFalse = func(string) {}
	}
	var ret *tailcfg.PeerChange
	pc := func() *tailcfg.PeerChange {
		if ret == nil {
			ret = new(tailcfg.PeerChange)
		}
		return ret
	}
	for _, field := range nodeFields() {
		switch field {
		default:
			// The whole point of using reflect in this function is to panic
			// here in tests if we forget to handle a new field.
			panic("unhandled field: " + field)
		case "computedHostIfDifferent", "ComputedName", "ComputedNameWithHost":
			// Caller's responsibility to have populated these.
			continue
		case "DataPlaneAuditLogID":
			//  Not sent for peers.
		case "Capabilities":
			// Deprecated; see https://github.com/tailscale/tailscale/issues/11508
			// And it was never sent by any known control server.
		case "ID":
			if was.ID() != n.ID {
				onFalse(field)
				return nil, false
			}
		case "StableID":
			if was.StableID() != n.StableID {
				onFalse(field)
				return nil, false
			}
		case "Name":
			if was.Name() != n.Name {
				onFalse(field)
				return nil, false
			}
		case "User":
			if was.User() != n.User {
				onFalse(field)
				return nil, false
			}
		case "Sharer":
			if was.Sharer() != n.Sharer {
				onFalse(field)
				return nil, false
			}
		case "Key":
			if was.Key() != n.Key {
				pc().Key = new(n.Key)
			}
		case "KeyExpiry":
			if !was.KeyExpiry().Equal(n.KeyExpiry) {
				pc().KeyExpiry = new(n.KeyExpiry)
			}