Merge pull request #1688 from ogayot/fix-list-drivers

drivers: fix empty list of drivers shown when it has not yet been retrieved

subiquity/server/controllers/drivers.py

@@ -48,8 +48,6 @@ class DriversController(SubiquityController):
     }
     autoinstall_default = {"install": False}
 
-    drivers: Optional[List[str]] = None
-
     def __init__(self, app) -> None:
         super().__init__(app)
         self.ubuntu_drivers: Optional[UbuntuDriversInterface] = None
@@ -57,7 +55,9 @@ class DriversController(SubiquityController):
         self._list_drivers_task: Optional[asyncio.Task] = None
         self.list_drivers_done_event = asyncio.Event()
 
-        self.drivers: List[str] = []
+        # None means that the list has not (yet) been retrieved whereas an
+        # empty list means that no drivers are available.
+        self.drivers: Optional[List[str]] = None
 
     def make_autoinstall(self):
         return {
@@ -84,7 +84,7 @@ class DriversController(SubiquityController):
 
         self.ubuntu_drivers = get_ubuntu_drivers_interface(self.app)
 
-        self.drivers = []
+        self.drivers = None
         self.list_drivers_done_event.clear()
         if self._list_drivers_task is not None:
             self._list_drivers_task.cancel()

subiquity/tests/api/test_api.py

@@ -1667,6 +1667,21 @@ class TestDrivers(TestAPI):
     async def test_desktop_source(self):
         await self._test_source('ubuntu-desktop', 'nvidia-driver-510')
 
+    @timeout()
+    async def test_listing_ongoing(self):
+        ''' Ensure that the list of drivers returned by /drivers is null while
+        the list has not been retrieved. '''
+        async with start_server('examples/simple.json') as inst:
+            resp = await inst.get('/drivers', wait=False)
+            self.assertIsNone(resp['drivers'])
+
+            # POSTing to /source will restart the retrieval operation.
+            await inst.post('/source', source_id='ubuntu-server',
+                            search_drivers=True)
+
+            resp = await inst.get('/drivers', wait=False)
+            self.assertIsNone(resp['drivers'])
+
 
 class TestSource(TestAPI):
     @timeout()