From 96b24abccb7a5ea7f4ed0a44e135cc1e92f0d027 Mon Sep 17 00:00:00 2001
From: Boris Rybalkin <ribalkin@gmail.com>
Date: Fri, 17 Jul 2026 18:09:19 +0100
Subject: [PATCH] devicestate: allow auto-refresh when registration is skipped
 (noregister)
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canAutoRefresh only returns true early when ensureOperationalAttempts >= 3
("we tried to get a serial for a while, allow refresh anyway"); otherwise it
requires a serial. Syncloud has no serial vault, so before PR #6 snapd kept
attempting registration, failed, and after 3 attempts that fallback enabled
auto-refresh — the perpetual "Initialize device" error was ugly but it is what
kept auto-refresh alive.

PR #6 (snapd 666) added the /run/snapd/noregister marker so ensureOperational
returns before ever attempting registration. That removed the error but left
ensureOperationalAttempts at 0, so the >= 3 fallback never fires and, with no
serial, canAutoRefresh returns false permanently. Every device that upgraded to
snapd 666 stopped auto-refreshing (snap refresh --time shows next: n/a); a
reboot does not help because the marker is recreated each boot and attempts
stays 0.

Treat the noregister marker as an explicit opt-out of registration that should
still permit auto-refresh, mirroring the marker check in ensureOperational.
---
 overlord/devicestate/devicestate.go      | 10 ++++++++
 overlord/devicestate/devicestate_test.go | 31 ++++++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/overlord/devicestate/devicestate.go b/overlord/devicestate/devicestate.go
index f7f7977f10c..f6391109a13 100644
--- a/overlord/devicestate/devicestate.go
+++ b/overlord/devicestate/devicestate.go
@@ -33,6 +33,7 @@ import (
 
 	"github.com/snapcore/snapd/asserts"
 	"github.com/snapcore/snapd/boot"
+	"github.com/snapcore/snapd/dirs"
 	"github.com/snapcore/snapd/gadget"
 	"github.com/snapcore/snapd/i18n"
 	"github.com/snapcore/snapd/logger"
@@ -129,6 +130,15 @@ func canAutoRefresh(st *state.State) (bool, error) {
 		return false, nil
 	}
 
+	// Syncloud runs no serial vault and deliberately skips registration via
+	// the noregister marker, so ensureOperational never attempts registration
+	// and ensureOperationalAttempts stays at 0. Without this the serial check
+	// below would disable auto-refresh forever. Allow it when registration was
+	// intentionally opted out.
+	if osutil.FileExists(filepath.Join(dirs.SnapRunDir, "noregister")) {
+		return true, nil
+	}
+
 	// Either we have a serial or we try anyway if we attempted
 	// for a while to get a serial, this would allow us to at
 	// least upgrade core if that can help.
diff --git a/overlord/devicestate/devicestate_test.go b/overlord/devicestate/devicestate_test.go
index 897883c322c..719563de818 100644
--- a/overlord/devicestate/devicestate_test.go
+++ b/overlord/devicestate/devicestate_test.go
@@ -1036,6 +1036,37 @@ func (s *deviceMgrSuite) TestCanAutoRefreshNoSerialFallback(c *C) {
 	c.Check(canAutoRefresh(), Equals, true)
 }
 
+func (s *deviceMgrSuite) TestCanAutoRefreshNoRegister(c *C) {
+	s.state.Lock()
+	defer s.state.Unlock()
+
+	canAutoRefresh := func() bool {
+		ok, err := devicestate.CanAutoRefresh(s.state)
+		c.Assert(err, IsNil)
+		return ok
+	}
+
+	// seeded, model, no serial, no registration attempts -> no auto-refresh
+	s.state.Set("seeded", true)
+	devicestatetest.SetDevice(s.state, &auth.DeviceState{
+		Brand: "canonical",
+		Model: "pc",
+	})
+	s.makeModelAssertionInState(c, "canonical", "pc", map[string]interface{}{
+		"architecture": "amd64",
+		"kernel":       "pc-kernel",
+		"gadget":       "pc",
+	})
+	c.Check(devicestate.EnsureOperationalAttempts(s.state), Equals, 0)
+	c.Check(canAutoRefresh(), Equals, false)
+
+	// registration deliberately skipped via the noregister marker
+	// -> auto-refresh without a serial or any registration attempts
+	c.Assert(os.MkdirAll(dirs.SnapRunDir, 0755), IsNil)
+	c.Assert(ioutil.WriteFile(filepath.Join(dirs.SnapRunDir, "noregister"), nil, 0644), IsNil)
+	c.Check(canAutoRefresh(), Equals, true)
+}
+
 func (s *deviceMgrSuite) TestCanAutoRefreshOnClassic(c *C) {
 	release.OnClassic = true