types/ptr: deprecate ptr.To, use Go 1.26 new

Updates #18682

Change-Id: I62f6aa0de2a15ef8c1435032c6aa74a181c25f8f
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

types/netmap/nodemut.go

@@ -12,7 +12,6 @@ import (
 	"time"
 
 	"tailscale.com/tailcfg"
-	"tailscale.com/types/ptr"
 )
 
 // NodeMutation is the common interface for types that describe
@@ -55,7 +54,7 @@ type NodeMutationOnline struct {
 }
 
 func (m NodeMutationOnline) Apply(n *tailcfg.Node) {
-	n.Online = ptr.To(m.Online)
+	n.Online = new(m.Online)
 }
 
 // NodeMutationLastSeen is a NodeMutation that says a node's LastSeen
@@ -66,14 +65,14 @@ type NodeMutationLastSeen struct {
 }
 
 func (m NodeMutationLastSeen) Apply(n *tailcfg.Node) {
-	n.LastSeen = ptr.To(m.LastSeen)
+	n.LastSeen = new(m.LastSeen)
 }
 
 var peerChangeFields = sync.OnceValue(func() []reflect.StructField {
 	var fields []reflect.StructField
 	rt := reflect.TypeFor[tailcfg.PeerChange]()
-	for i := range rt.NumField() {
-		fields = append(fields, rt.Field(i))
+	for field := range rt.Fields() {
+		fields = append(fields, field)
 	}
 	return fields
 })

types/netmap/nodemut_test.go

@@ -14,7 +14,6 @@ import (
 	"tailscale.com/tailcfg"
 	"tailscale.com/types/logger"
 	"tailscale.com/types/opt"
-	"tailscale.com/types/ptr"
 )
 
 // tests mapResponseContainsNonPatchFields
@@ -117,7 +116,7 @@ func TestMutationsFromMapResponse(t *testing.T) {
 			name: "patch-online",
 			mr: fromChanges(&tailcfg.PeerChange{
 				NodeID: 1,
-				Online: ptr.To(true),
+				Online: new(true),
 			}),
 			want: muts(NodeMutationOnline{1, true}),
 		},
@@ -125,7 +124,7 @@ func TestMutationsFromMapResponse(t *testing.T) {
 			name: "patch-online-false",
 			mr: fromChanges(&tailcfg.PeerChange{
 				NodeID: 1,
-				Online: ptr.To(false),
+				Online: new(false),
 			}),
 			want: muts(NodeMutationOnline{1, false}),
 		},
@@ -133,7 +132,7 @@ func TestMutationsFromMapResponse(t *testing.T) {
 			name: "patch-lastseen",
 			mr: fromChanges(&tailcfg.PeerChange{
 				NodeID:   1,
-				LastSeen: ptr.To(time.Unix(12345, 0)),
+				LastSeen: new(time.Unix(12345, 0)),
 			}),
 			want: muts(NodeMutationLastSeen{1, time.Unix(12345, 0)}),
 		},