fix(config_flow): F2 — MAC-less zeroconf discovery calls the audited _async_handle_discovery_without_unique_id helper and guards against a same-host duplicate prefill, so re-discovery can't stack entries; the import guard reads entries via the base _async_current_entries helper; TestMacLessDiscoveryF2 pins helper call + one-entry outcome (t32)

custom_components/nvidia_shield/config_flow.py

@@ -370,6 +370,19 @@ class NvidiaShieldConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
                     )
                 return self.async_abort(reason="already_configured")
             self._abort_if_unique_id_configured()
+        else:
+            # t32 F2 (review rider): MAC-less discovery cannot carry a
+            # unique_id — HA's helper records the uniqueness-less discovery
+            # (the same discovery context can't stack duplicates) and the
+            # host guard keeps a second discovery of an already-configured
+            # host from stacking another prefill.
+            self._async_handle_discovery_without_unique_id()
+            for entry in self._async_current_entries():
+                existing_host = entry.options.get(
+                    CONF_PROTOCOL_HOST
+                ) or entry.options.get(CONF_ADB_HOST)
+                if existing_host and existing_host == host:
+                    return self.async_abort(reason="already_configured")
 
         # First-time setup: pre-filled user step
         return await self.async_step_user()
@@ -490,7 +503,7 @@ class NvidiaShieldConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
 
         # duplicate guards
         yhost = block.get(CONF_ADB_HOST) or block.get(CONF_PROTOCOL_HOST)
-        for existing in self.hass.config_entries.async_entries():
+        for existing in self._async_current_entries():
             ehost = existing.options.get(CONF_PROTOCOL_HOST) or existing.options.get(
                 CONF_ADB_HOST
             )