fix(controller): read config status from DB in reconciliation

The _reconcile_modified_status method was reading config.status from
the cached device object (get_device uses cache_memoize with a 30-day
TTL). When the config status changed to "modified" after the device
was cached, the reconciliation would see the stale cached status and
skip the reconciliation.

Fix: query Config directly from the database using Config.objects.get()
instead of accessing device.config, which may return cached state.

Also add a test that verifies reconciliation works even when the
device object is served from cache.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Codex

openwisp_controller/config/controller/views.py

@@ -187,10 +187,21 @@ def _reconcile_modified_status(device):
         "modified" state for longer than the grace period and the device
         is actively polling (proven by this very checksum request), we
         set the status to "applied".
+
+        Note: the device object may come from cache_memoize (30-day TTL),
+        so we must read config status fresh from the database to avoid
+        acting on stale cached state.
         """
         from django.utils import timezone
 
-        config = device.config
+        from ..models import Config
+
+        # Read config fresh from DB to bypass any cached state on the
+        # device object (get_device is cached with a 30-day TTL).
+        try:
+            config = Config.objects.get(device=device)
+        except Config.DoesNotExist:
+            return
         if config.status != "modified":
             return
         grace = DeviceChecksumView._STATUS_RECONCILE_GRACE_SECONDS

openwisp_controller/config/tests/test_controller.py

@@ -326,6 +326,34 @@ def test_device_checksum_no_reconcile_within_grace_period(self):
         c.refresh_from_db()
         self.assertEqual(c.status, "modified")
 
+    def test_device_checksum_reconcile_bypasses_device_cache(self):
+        """
+        Reconciliation must read config status from DB, not from
+        the cached device object (get_device has a 30-day cache TTL).
+        """
+        from datetime import timedelta
+
+        from django.utils import timezone
+
+        d = self._create_device_config()
+        c = d.config
+        url = reverse("controller:device_checksum", args=[d.pk])
+
+        # First request populates the get_device cache
+        response = self.client.get(url, {"key": d.key})
+        self.assertEqual(response.status_code, 200)
+
+        # Now set status to modified and backdate past grace period
+        c.set_status_modified()
+        Config.objects.filter(pk=c.pk).update(
+            modified=timezone.now() - timedelta(seconds=600)
+        )
+
+        # Second request should reconcile even though device is cached
+        response = self.client.get(url, {"key": d.key})
+        self.assertEqual(response.status_code, 200)
+        c.refresh_from_db()
+        self.assertEqual(c.status, "applied")
 
     def test_device_checksum_bad_uuid(self):
         d = self._create_device_config()